Why Shorter Cranks Are Better (According To Science)

Nov 16, 2021
by Seb Stott  

There aren't many win-wins in mountain-biking, but shorter crank arms could be just that.

Most bikes have crank arms between 170 and 175 mm long, and it's been that way for a long time. Some brands spec 170 mm cranks on their smaller sizes and 175 mm cranks on the larger sizes, and you can even buy 172.5mm cranks aftermarket, suggesting that the ideal length for pedalling ergonomics, efficiency, power and ground clearance must be somewhere in that range. But there's a fair bit of published science on crank length which tells a different story.

Trawling Google Scholar served up seven published studies looking into the effects of crank length on pedalling performance. Given the bike industry's near-universal spec choices, you might imagine they found that the ideal crank length was somewhere in the region of 170-175 mm, or maybe that longer crank arms might improve pedalling power to some extent, given that mountain bikes need to compromise between efficiency and ground-clearance. They found nothing of the sort.

In the rest of this article, I'll briefly summarise the methods and findings of each study, then at the end, I'll sum up and give my own take. But first, a little theory.

The Theory

A commonly made argument is that longer cranks offer more leverage, meaning more torque can be generated for a given force at the pedal. This is true, but leverage comes at a cost. If you can move your pedal with a certain force and at a certain speed around the circumference of the pedalling circle, a longer crank will generate more torque but at a lower rotational speed (rpm), because the circumference is bigger. Power is just force times speed or torque times rotational speed, so either way, the power is the same (at least in theory).
This thoroughly amateurish diagram shows that for a given distance travelled by the pedal, a longer crank will turn through a smaller angle. So for a given pedal speed, a longer crank has a lower rpm, which cancels out the increase in torque.

It's well-documented that riders naturally pedal at a higher rpm when using shorter cranks; so to some extent, the reduced torque is compensated by a higher cadence.

This isn't to say that crank length doesn't matter, but the difference comes in the biomechanics - do human bodies prefer to do a shorter range of motion more frequently (shorter cranks) or a longer range of motion less frequently (longer cranks)? Or more accurately, where does the optimum between those extremes lie? That's a question that needs to be found out through experimentation on real-life people.

I've searched out all the scientific articles I can find on crank length; seven papers in total. They all have slightly different methods and ways of measuring things, but they all come to a similar conclusion: longer cranks are not better.

...
Most studies involved measuring power output on static bikes, which may or may not have looked like this.

What the Science says

This 2001 study by J.C. Martin & W.W. Spirduso is one of the biggest and most comprehensive on crank length. They measured the maximum sprint power output on a static bike with sixteen trained cyclists, each using a wide range of crank lengths (120, 145, 170, 195, and 220 mm).

Perhaps unsurprisingly, the lowest power outputs were recorded with the most extreme (120 mm and 220 mm) crank lengths. The highest power output was recorded with the 145 mm crank, although the difference wasn't large or consistent enough to be considered significant compared to the 170 mm or 195 mm cranks. The difference in power between the "best" (145 mm) and "worst" (220 mm) crank was just 3.9%

As you'd expect, as crank lengths increased, the cadence decreased, from 136 rpm for the 120mm cranks to 110 rpm for the 220mm cranks. In other words, the body adapts by changing cadence to suit the crank length.

Looking at all the data from all sixteen cyclists and all five crank lengths, the authors estimated the optimal crank length for sprinting was 20.5% of leg length or 41% of tibia length. But in either case, the correlation was too weak to draw any firm or precise conclusions. The main takeaway here is that sprint power output varied very little, especially across the middle three sizes (145, 170 and 195 mm) which is a much wider range of crank lengths than typically used.

Here's how the authors put it: "Even though maximum cycling power was significantly affected by crank length, use of the standard 170 mm length cranks should not substantially compromise maximum power in most adults." In other words, within reasonable limits, the ratio of leg length to crank length doesn't matter too much for sprint power.



Is there a disadvantage for kids riding adult-sized cranks?


In 2002, Martin and Spirduso built on the above study by looking at it in another way. They tested maximum power again, this time with 17 boys aged 8–11 years. Their maximum sprint power was tested with a standard 170 mm crank and with an "optimal" crank length which, based on their previous study, was calculated to be 20% of their leg length. The "optimal" cranks were therefore shorter than 170 mm.

Although there was a difference in cadence (129 rpm for the shorter cranks and 114 rpm for the 170 mm cranks), they found no significant difference in the boys' power output in either case.



What about aerobic efficiency as opposed to maximum sprint power?


This 2002 study by J. McDaniel et al. had nine trained male cyclists pedal at a submaximal (aerobic) power output with 145, 170, and 195 mm crank arms, each at four different cadences (40, 60, 80, 100 rpm). This gave twelve different pedal speeds (crank length x cadence). They did this at 30, 60, and 90% of their Lactate Threshold, while the volumes of oxygen they consumed and CO2 they produced were measured to determine the metabolic cost of cycling at each power output and each crank length.

They found that the metabolic cost of cycling was strongly correlated to the pedal speed (crank length x cadence) but wasn't related strongly to the cadence or crank length per se. In other words, riding with shorter cranks requires a faster cadence (and longer cranks a slower cadence); but with the right cadence, the crank length doesn't significantly affect the metabolic cost of pedalling at a given power output.

Here's how it's put in the paper: "even with our wide range of pedaling rates, pedal speeds, and crank lengths, muscles' ability to convert chemical energy to mechanical work was remarkably stable."



What about for mountain bikers?


In 2009, Paul William Macdermid & Andrew M. Edwards tested seven female cross-country athletes with 170, 172.5 and 175 mm crank arms. Their peak power was measured at a constant cadence (50 rpm) and then at maximal aerobic capacity.

No differences were observed in power output, even when cadence was fixed at 50 rpm. However, the time taken to reach peak power in a spint was significantly less with the 170 mm cranks compared to the 175 mm ones.

The authors suggest this could represent an advantage: "The decreased time to peak power with the greater rate of power development in the 170 mm condition suggests a race advantage may be achieved using a shorter crank length than commonly observed. Additionally, there was no impediment to either power output produced at low cadences or indices of endurance performance using the shorter crank length and the advantage of being able to respond quickly to a change in terrain could be of strategic importance to elite athletes."



But do extreme crank lengths lead to excessive strain in specific joints?


In 2011, Paul R. Barratt et al. looked into the relative contribution of different leg joints towards pedalling power, with crank lengths of 150, 165, 170, 175, and 190 mm. Although there were differences in the hip and knee joint contributions when comparing the 150 and 190 mm crank arms and when cadence was fixed at 120 rpm, there were no differences when cadence was allowed to vary to suit the crank length. "Crank length does not affect relative joint-specific power once the effects of pedaling rate and pedal speed are accounted for. Our results thereby substantiate previous findings that crank length per se is not an important determinant of maximum cycling power."



What about with untrained cyclists?


In 2016, Ventura Ferrer-Roca et al. measured both the aerobic efficiency and the range of motion at the leg joints in twelve amateur cyclists. Heart rate and gross efficiency (pedalling work done per calorie burned) were measured while pedalling at a fixed aerobic power output. They did this with three crank lengths 5 mm apart.

Again, there were no differences in heart rate or gross efficiency at any of the crank lengths tested. However, longer crank arms measurably increased the range of motion of the hip and knee joints which, the authors say, could be a negative. "the biomechanical changes due to a longer crank did not alter the metabolic cost of pedalling, although they could have long-term adverse effects. Therefore, in case of doubt between two lengths, the shorter one might be recommended."



What about for stand-up pedalling?


Finally, in 2021, Sumin Park et al. looked into standing cycling. Ten participants cycled out the saddle at sub-maximal (aerobic) power while biomechanical parameters, motion data and pedal reaction forces were measured. With longer cranks, more power was absorbed during the upstroke of the pedalling cycle. "Consequently," the authors say, "longer crank lengths require increased propulsion power by the lower limb muscles during standing cycling compared to shorter crank lengths. Therefore, shorter crank lengths are recommended for stand-up bicycles to avoid fatigue."

Chromag Dagga Pedal
Shorter cranks are common in downhill for a reason.

Conclusion

The main takeaway from the published science is that crank length either doesn't affect pedalling performance, or there's a possible advantage to shorter cranks. Although one paper found a small disadvantage with very extreme crank lengths (120 mm or 220 mm), there is no evidence of a significant difference in maximum power output or efficiency when using crank lengths as far apart as 145 and 195 mm. This is because, as crank length decreases, cyclists pedal at a higher cadence to compensate.

Three of the seven papers put forward possible benefits to shorter cranks, while the rest found no difference. One paper found shorter cranks reduced the time taken to increase power output in a sprint; one recommended shorter crank arms for standing cycling to reduce fatigue; another noted that longer cranks increase the range of motion of the hip and knee joints, which they say "could have long-term adverse effects".

One study estimated that the optimal crank length (for sprinting) is about 20.5% of the cyclist's leg length. Leg length is typically around 45% of height, which would imply an optimum crank length of about 9.2% of total height. That rule of thumb would put the ideal crank for someone of average male height (175cm or 5'9") at around 161 mm, or 150 mm for the average female height. But remember these are very rough numbers and the main takeaway is that, within sensible limits, crank length doesn't matter much in terms of pedalling performance.

As mountain bikers, all we need to know is that running 10 mm shorter cranks won't slow you down when pedalling, but that much more clearance is a huge difference in terms of reducing the risk of those heart-stopping and axle-bending stalls when the pedal catches a rock. Of course, you could also increase the BB height to achieve this, but that has its own list of disadvantages which could fill another article.

There are a couple of practical challenges to going to shorter cranks. Most importantly, the requirement to pedal at a higher cadence will require easier gearing (going from 175 to 165 mm cranks should be paired with swapping a 32t to a 30t chainring to compensate for the reduced leverage and allow for higher cadences). This may result in some ribbing from less educated riders. If the gearing isn't adjusted, the shorter crank arm effectively gives a harder gear in terms of the force required at the pedal to create a given propulsive force at the wheel, potentially leading to more strain on the body when you run out of gears.

Also, shortening crank length by 10 mm should ideally be paired with raising the saddle height by 10 mm so the leg extension with the pedal at the bottom of the circle is the same. For a given dropper post length, this means the saddle will be 10 mm higher when descending, so fitting a longer dropper post may be worth considering too. Finally, from experience, when fitting shorter cranks it may take a few rides to get used to the higher cadence.


539 Comments

  • 781 7
 Pick a crank length and be a dick about it.
  • 1389 4
 pick a dick length and be a crank about.
  • 40 0
 Is there anything I’ve not to be a dick about these days?!
  • 89 1
 @savagelake: 2" is peak performance
  • 9 0
 @mashrv1: no...not really...
  • 24 1
 Thats not what she said
  • 14 0
 @bforwil: a fellow man of culture
  • 66 0
 A 175mm crank is 6.9" (rounded up).
  • 24 0
 @Highlander406: Niiiicccceeee
  • 18 1
 @savagelake: thanks for the laugh at work. Probably my favorite PB comment of the year.
  • 3 0
 @savagelake: ouch *cringes*
  • 9 1
 @Highlander406: always round up
  • 20 0
 Here we go. The Classifieds will be inundated with 175mm Cranks and now the used price of 165mm cranks just skyrocketed.....
  • 6 2
 @erikvehmeyer: so 6 1/2 inches ---> 1 foot?
  • 69 1
 @Three6ty: wait till the crowd realizes 26" wheels are easier to throw around and provide more room under your ass for bunny hops and manuals
  • 35 0
 @baca262: Can't wait. I have a garage full of 26" wheels.. I'm Rich Bitch.....
  • 4 1
 @ReformedRoadie: Only if you hit it twice.
  • 27 1
 Reminds of when FSA thought they'd sell 165mm cranks to the DH crowd, but just used their 175mm cranks arms and drilled the hole in them 10mm further up the arm.

Damn things were like shovels when you pedaled a DH bike.
Here's a set of FSA road cranks that were done that way:

i.ebayimg.com/images/g/iIUAAOSwl8NhZbuk/s-l1600.jpg
  • 4 1
 @blowmyfuse: the 90s Sugino cranks used the same arms for the 170 and 175 lengths. Others must have done it too.
  • 11 1
 @savagelake: I agree, 10mm would make a big difference in my love life.
  • 12 6
 I'd like to take this moment to point out there is an advertisement for a skiing video on PB's homepage right now....? In other news, if you scroll down from the skier story you get to learn about studying witchcraft...

Clearly Pinkbike is now trying to turn us into QAnon...
  • 14 0
 Now all they need to do is send this article to Shimano, so they can believe it and actually have stock of 165mm cranks!
  • 2 0
 @blowmyfuse: I like to measure based on distance per second. So 1 x 12 would be the same as 2 x 6 the same as 3 x 4 etc. It's all in the hips.
  • 3 0
 @freeriderayward: Ive had some 165 XT's on backorder for a while. I have zero expectations for when I'll actually get them.
  • 4 0
 my cranks go to 11
  • 9 0
 I've been saying this for years!! As a test, threw on some 155mm cranks and... the world didn't end! Friendly on the knees, less pedal strikes, all good.
  • 20 1
 Pick a length, and crank your dick about it.
  • 5 2
 @savagelake: Length a crank and about dick a pick
  • 1 0
 @mashrv1: no, one can even not be a dick, and be a dick about it
  • 6 5
 I’ll have a chat with your mum tonight about length and cadence.
  • 6 0
 @Three6ty: I've already snatched up all the halfway decent 165mm cranks and re-posted them at Toyota Tacoma prices.
  • 3 2
 @savagelake:
I chose not to choose dick length. I chose somethin’ else. (c) Trainspotting
  • 3 0
 @joebmx: Toyota Tacomas aren't even at Tacoma prices anymore. They're at Land Cruiser prices. And Land Cruisers are at Bently prices.
  • 1 0
 @nskerb: a “fallow” man of culture
  • 1 2
 @mashrv1: Why does I've instead of I have sound strange here? I feel like I might need to be more open grammatically. I also don't know what grammatically means.
  • 4 0
 Did anybody mention yet: Dick Pound
  • 1 0
 Dick pick about crank it length.
  • 1 0
 She told me my crank was just the right size.
  • 1 0
 @baca262: Well, I went a bit further. Looking at the newer bikes with the slack head tune angles, my old Banshee Sirocco looked so steep, I had to do something. I like it to much to part with so I put a 24 x 2.8 on the back. The cushion alone is great, and with the new 50mm stem, handling is better, maybe way better and the new 160 Lekkie look nice with Lekkie 42 tooth. To be honest, I don’t notice any difference from the typical 175’s. Also I had not been on bike much lately, I retired a few years ago. I commuted by bike for 20 years. Now I just ride for fun. The BBSHD and 52v 20ah battery has made all things new again.
  • 1 0
 @savagelake: stupid comment
  • 1 0
 @gamtnbkr: there are no stupid comments, just stupid questions... Smile
  • 2 1
 @baca262: Newton says yes to you on all points. I’ve got bikes in my garage ranging from the year 2000 to 2021. The new bikes get a lot of things right, but there is no way that anybody can say 26” wheels don’t rail corners easier than big wheels. Wish someone would build a bike with modem geo and components and nimble little 26” wheels. I’ll pre-order now! I’ve got the technical riding skills and really enjoy the smaller wheels TBH. Don’t need the tractor effect of big wheels in the tech stuff.
  • 1 0
 @Three6ty: Straight Circumference Homey
  • 458 3
 I run a mullet crank set-up: Party on the left, Business on the right
  • 51 1
 Oooh yeah. Keeping the party going on my bike running an 800mm bar left of the stem, 760mm on right. Damn tree broke off end of the bar.
  • 120 0
 @DirkMcClerkin: Damn, a 1,560mm bar is a VIBE!
  • 9 0
 You all might have something here. I corner better to the left: so for better right corners maybe I need shorter cranks on the right and the bar to stick out farther to the left???

Or maybe they'll start creating big spiraling DH tracks like Nascar and I can only turn left the whole time...? Smile
  • 10 0
 I hope you run an oval chainring with that
  • 2 0
 @stiingya: Many years ago a buddy of mine would cut his bars shorter on one side so he could get his tables more flat. I think it was a thing that some bmx guys were doing at the time. I rode his bike around a few times it felt really wierd. That said I do find myself riding with my left hand a bit farther in on the bars than my right and actually moved my brake lever in a bit, it might just be because I'm old and that wrist is more worn out than the other one.
  • 4 0
 @Cerberon: half oval, half round
  • 1 0
 ah the julian molina method.
  • 2 0
 @brahmvanh: THAT is funny. Nice quick witty math! Bravo.
  • 2 0
 Be sure to pair the right crank with a clipless pedal while running flats on the left.
  • 134 1
 yeah but bigger cranks are bigger
  • 57 0
 Case closed.
  • 10 0
 It's science!
  • 7 1
 Longer cranks = more manliness. Its just science.
  • 10 0
 I want more, because more is more-er
  • 1 0
 180's for life!!
  • 124 0
 *Puts tinfoil hat on*
The real reason for this article and persuading people that shorter cranks are superior is to gain a wider audience of prospective buyers for the Grim Donut when Outside inevitably starts selling it.
  • 90 0
 I'm going to run with this.
  • 10 0
 @brianpark: 140 cranks on my Grim Donut Please and 300mm BB height if you wouldn't mind.
  • 6 0
 You're just a long-crank industry schill!
  • 10 0
 You're on the right track but it's actually PB have been paid by Big Drivetrain to convince everyone their current cranks are too long, so they can release a new crank length standard, and people will flock to buy it.
  • 9 3
 @brianpark: *WE are going to run with this! Chris Cocalis the Pivot CEO is going to LOVE this!

Be safe be well,
Incognito Robin
  • 6 0
 Won’t there still be pedal strikes as the norm while pedaling anything longer than 60mm cranks? Isn’t the grim donut’s bottom bracket height actually measured in mm below the surface of the earth
  • 8 0
 @schlockinz: In the low setting of the 175mm long flip chip of the Donut, the lowest pedal position at 25% sag is 200mm below surface. Test rider Chuck Norris says in Rocky terrain every pedal stroke feels like a roundhouse kick through a brick wall but has not discovered any drawbacks yet.
  • 3 0
 @melonhead1145: 148 mm cranks are the future...
  • 2 0
 @seb-stott: not 26" cranks?
  • 1 0
 150mm cranks and matching BB drop?
  • 7 0
 @schlockinz: I hear there was some debate in the marketing meeting about this. One of the designers is a flat earther so didn't account for the reduced clearance at the BB over such a long wheelbase.

*Puts on sculpted tin-foil sombrero*
  • 6 1
 @brianpark: you guys haven't gone far enough. I want my pedals welded directly to the BB spindle
  • 2 0
 Regardless, it's actually one of the most useful articles they've published all year. And with a bit more work they could probably get legitimately published for a meta-analysis of the literature on this topic
  • 90 3
 I start w/ 175mm length, then moved to 170mm length thinking it would be the best of both worlds. Now I'm on a spire that has 165mm and the only thing I've noticed are nothing but pros. Less pedal strikes, more balanced when descending, and no noticeable torque issues. I'm 165mm length for life now.
  • 282 0
 Great, now I hate my cranks.
  • 8 0
 I’ll second this. I switched to 165 2 years ago, absolutely no noticeable difference in power but immediately noticed an increase in comfort (less joint movement), and better ground clearance, especially on big squishy bikes where stand up pedals means lots of shock bouncing.
  • 17 1
 @tfriesenftr: Were there other variables? I tried a set of 165's, the difference in climbing wasn't subtle. I pushed up everything
  • 10 0
 Ever since I've been overhauling my own bikes, I'd get the shortest crankset I can find, which is 165mm from Shimano. It's really hard to find anything that's shorter for mountain biking (if you're lucky, you may be able to find a 160mm - again from Shimano). I learned this by reading specs from bikes for road racing and especially for time trials and triathlons where riders are bent over. They have short crank arms so that their cyclical movements are not more exaggerated, especially when limiting movements on the hip while one is bent over on an aerodynamic tuck. Anyway, the fit on a bike with shorter crank arms was actually a lot better than the usual 170mm or 175mm stock cranks (less of a vertical distance of movement). I would almost guarantee that if you have knee problems, you'd be better off with shorter crank arms. I've been telling my friend, who is 6'4+'', that he should go that route. He'd always come back with the torque analogy and I always kept telling him there's probably no difference in how much power one would lose or gain with the length of the arm. He finally converted to shorter crank arms (at 165mm) and he loves it - good on his knees and a better pedal clearance (one full centimeter). The thing that most people think of with the longer arms having more power in their pedaling stroke is with the torque wrench or the breaker bar. It's different with cycling since you're using gears to do all the work.
  • 5 10
flag baca262 (Nov 16, 2021 at 11:40) (Below Threshold)
 175 is for uphill grinding
  • 14 2
 @mobiller: Did you see the part in article where you have to go down a chainring size or two?
  • 23 1
 I’m on 165mm shimano cranks, and I’m not going back

My favourite thing is to watch fellow riders’ faces contort and malfunction as they realise that everything else on the drivetrain is SRAM

Big up to oneup chainrings for allowing this drivetrain blasphemy to occur
  • 19 1
 @CSharp: Canfield now makes a 155 mm crank and it appears to be in stock
  • 16 1
 @CSharp: Canfield make 160 and 155 cranks.
  • 10 0
 I'll second, third, fourth and fifth this. I had 175s on my Jeffsy and absolutely destroyed my favorite Time Speciale 8s due to pedal strikes. When I built up a 2020 Enduro, I chose 170 cranks and I still had a huge toe strike that sent me otb and ripped off half of my shoe sole. I immediately switched to 165. I could notice I had to grunt a little more on the uphills for the first couple of rides, but after that, I just have to say that 165 cranks (and beer) are proof that God loves us and wants us to be happy.
  • 1 0
 Too much 175mm cranks on back market already. You shouldn't have told them!
  • 4 1
 Never paid much attention or thought of crank length until last couple of years when I bought another bike with 170mm cranks (normally use 175mm). Here is what I have noticed. The shorter 170mm cranks definitely fit my leg length better, but they are slightly harder to pedal with a little less leverage. Yeah, less pedal strikes are the plus for shorter cranks. However, moving your seat position forward/aft or cleat position forward/aft can help with fitting to longer or shorter cranks.
  • 3 0
 @paulestuart: Trailcraft makes 140 and 152.5 cranks with shimano BB standard and SRAM chainring interface. Awesome for kids, but also relatively light an affordable in general.
  • 1 0
 @Niki82: they actually make a 150mm crank too....
  • 5 1
 I went from 175 to 165 and didn't like it. It felt all funny and stuff. Then I went to 170 and stayed there. Now thanks to this article I'm not happy anymore and have to try 165s again. My son had a Haro Mini BMX with 152 cranks on it when he was six and the knee articulation was insane. Totes could have done with 132s on that chur.
  • 5 0
 @paulestuart: You just made a sale for Canfield.
  • 2 0
 Same here - been on 165s for years. RF SIXCs but I don't believe they come in that size anymore.
  • 2 0
 @CSharp: google 5Dev. I think they are making down to 155 mm arms.
  • 1 0
 How tall are you and what is your natural stance (ie what do naturally land at after a short jump?).
  • 1 0
 I threw on some 155mm cranks, all good. Just gotta adjust your gearing a bit. Better on knees, less pedal strikes, all bueno!
  • 4 0
 @nzandyb: zink rides canfield cranks too.
  • 1 0
 In one of his How to Bike videos, giant tall lanky Ben Cathro said he's switched to 170mm cranks. I figured if he's on 170mm, 5'8" me should be on something way shorter than that. I'm planning on switching to at least 165mm cranks this winter.
  • 10 7
 @st-lupo: It makes sense on bikes with low bottom brackets to use a crank that is shorter. I agree that 165's require more grunt though, and its really annoying that the article failed to acknowledge this in seemingly any way.
  • 1 0
 On the three bikes i ride i got 165, 170 and 175mm crank respectively. I don't feel like I'm losing power on either, but i do notice the pedal strikes on 175, it's on a HT with proper low BB. If only a cheap 165 was readily available (SRAM GXP or Shimano) I'd be super happy.
  • 7 0
 @VTwintips: What about where they say that the shorter cranks require a lower gear (but enable a higher cadence to compensate)?
  • 1 0
 @mobiller: everything. Compare the similarly gripping testimony of your centenarian echo @50percentsure. The bro variable. Torque is also what breaks the rear wheel loose
  • 4 0
 @nzandyb: When I saw this article, I immediately assumed canfield was behind it.
  • 3 0
 @paulestuart: you must be thinking of their 155mm boat anchor
  • 8 4
 @tfriesenftr: a hundred bucks says you never ride uphill. 165s are really noticeable compared to 175 when climbing. Anyone who says their not is a bold face liar.
  • 3 1
 Yup, switched from 175 to 170 and now on 165’s and love them.
  • 2 0
 @mhoshal: Fire road climbing sucks, who cares? 165 are way better for short, steep, super-tech climbing. Which sucks less than miles of fire road.
  • 1 1
 @mhoshal: I don't think it matters at all - buck up.....
  • 2 0
 I just bought SRAM XX1 Quarq 165mm cranks, they are meant for a power meter, but you can buy aftermarket 8 bolt standard (or oval) chainrings in the 8 bolt pattern that mount directly to the crank. 8 bolts instead of 3, but they are in stock now. The combo is the same weight as XX1 SL and about $15 less.
  • 1 0
 @bravefart: A Shimano chainring would have worked just fine with the SRAM chain.
  • 4 0
 @CSharp: Canfield AM cranks go down to 155mm and are in stock (for another few hours, now that this article is out)
  • 5 0
 @Tambo: that's a fair point. you could phrase it in a positive way however you wish though, to be fair. you could say big cranks enable a low cadence or small cranks enable a high cadence. the question, i think, is what cadence do you prefer? I don't have data to back this, but my understanding is that a steroided lance armstrong preferred an unhumanly high cadence of 120rpm but a normal tour de france person liked a lower cadence of 80. So I would think that the enabling of a high cadence doesn't mean much. Maybe that's the graph we all desire???

As a relatively tall person (187cm or 6'3") 165's feel awkwardly short and obnoxious although they provide more ground clearance. 170's feel pretty natural and great on a dirt jumper in particularly, as stated somwhere below. And 175's feel perfect in general, albeit slightly long on highly technical terrain, only for the sake of long dh's where your leg imbalance get's tired, or for uphills with pedal strike. But this is a learned preference.

Thanks for the comment.
  • 5 1
 @VTwintips:

I'm 6'3", 190.5cm.

Ran the optimal crank arm length formula in the article (height in cm x .092). Results? Almost exactly 175mm.

Guess I'll stick with the 175mm crank arms I've always run ....
  • 1 0
 @adrennan: Stealth marketing at it's finest.
  • 5 0
 I'm 6'2". I went from 175 to 170 in 2012, and rode faster, especially on climbs. I'm not very flexible. In 2017 I put on 165s. 1 year ago I put on 153's. Two days ago I put on 140's. The 140's were the first with any negative artifacts, but there are a couple more positives. I have 4 hours on them. I have about 300 hours on the 153's.

Something is wrong with the "scientific" studies. I don't know what they are missing, but every time I put on shorter cranks I go faster for the same effort. And not just a little faster.

I think what is missing is a subject common to dirt bikers: Powerband. On 175's I had useful power from 70 to about 95 rpm. Because I am now able to use much better pedaling technique, my useful range is now about 50 to 120 or so. One gear, double your speed. Yeah, that's fun.

A month ago I wrote an 8 page article on this subject. I've shown it to 4 people, and they all gave me tinfoil hats. Oh well. They'll never put on a set and actually test it, because that's human nature.
  • 1 0
 @CSharp: www.bikesmithdesign.com
They only fit BSA, but he makes experimenting dirt cheap. I've purchased 153, 140 and 120. I've ridden the first 2, my arthritic wife has the 120's
  • 1 0
 @t-1: I like the outside box thinking....it's how paradigms shift. Where'd you get the shorter cranks?
  • 1 0
 @VTwintips: Definitely "short" and "long" cranks are relative, and there's personal preference and variation from rider to rider. What we really need is bike geometry that reflects this as far as possible; higher BBs on larger sizes, because they're more likely to be using a longer crank. The slight reduction in stability from the higher BB will probably be offset by the longer wheelbase, so overall feel will be similar to a smaller size.
  • 1 0
 @t-1: tell someone a crank is 'short' and they're already biased against it. Seems like femur length is more important than leg. Moving from 170 to 165mm, I had the sensation that bike was smaller and that stance was weaker in landings to flat with crank at zero degree. This sensation quickly disappeared. Moving back to 170 after a while, I had knee pain--no more 170. If you post your article in your profile, someone else might read or steal it
  • 1 1
 @ceecee: Femur length definitely is a bigger factor than crank length. Longer legs in general create more leverage, but you cannot swap out your femurs and get longer ones.Wink In my experience is that longer cranks do create more leverage, but you still have to fit the correct crank to leg size.
  • 37 3
 i get all the issues of stroke length and joint pain and all that, but to me it's more about not smacking the lunchbox sided rock with my pedal while on a particularly crappy tough climb that I care about.
  • 22 3
 Yes, and I think that’s the take-away: you can choose the shortest crank you want to achieve the clearance you need, without any downsides to power or performance. You just have to adjust chainring size.
  • 12 2
 @dominic54: For a given frame, shorter cranks means a higher saddle for pedaling which means a higher center of mass. I have never tried it, but I suspect a bit less stable seated position in the rough climbs. Can you really notice a 10 mm increase in center of mass? (Going form a 175 to a 165mm crank)
  • 4 21
flag mtnbiker831 (Nov 16, 2021 at 11:25) (Below Threshold)
 @notai: Absolutely, but changing your crank arm length doesn’t change center of mass. That has to do with bb height
  • 11 1
 @mtnbiker831: Well it might not change centre of mass of the bike, but it absolutely changes center of mass of your system in motion (rider + bike), which is what matters more.
  • 4 2
 @mtnbiker831: I concur with this. I was about to state the same face. Potentially you may have a minute rise in CoM in a fully extended leg(bottom of stroke), but in all realities, this isn’t a stable position anyway.

Descending is still the same CoM when the cranks are level. Arguably, with your legs closer together when descending , would you level out the strain and fatigue to your rear supporting leg?

I’m guessing it’s a universal sizing that the bike brands spec on the bikes. This may well be due to frame sizing and perceived rider heights .

Would be interesting conducting actual back to back references/timings on proper trails and not static bikes @pinkbike:
  • 3 0
 @notai: Only when seated of when standing with one pedal down. When your pedals are even (normal position when descending) bb height is the deciding factor. When standing with one pedal down you can simply bend your knees slightly more (0,5 - 1 cm is easy to compensate for)
  • 4 0
 @2-1RacingUK: how could you possibly not have a higher center of mass of a bike and rider (in seated position) if you raise your seat?
  • 4 0
 @notai: BUT, if cranks were shorter, bicycle manufacturers could start dropping BB heights, this would give the same seated height for pedaling, but a lower center of gravity descending when the cranks are parallel to the ground!
  • 5 0
 @nzandyb: I think BB heights are low enough already, they really factor into the loss of playfulness in most new bikes.
  • 2 0
 @notai: When you're climbing a technical trail with roots and rocks, especially big ones, you're actually not fully seated. The weight or the center of mass actually shifts forward to get the bike up and over these obstacles. But that weight shift is only enough to not get the rear wheel to slip out. Also, with a shorter crankset and the hips shifted forward, the leg articulation is less. So, you actually get more power on the down stroke as opposed to more knee articulation, which may not be optimal on that downstroke (again, we're not talking about the leverage of the crank arms as opposed to the leverage of the rear cassette on the rear wheel - more torque needs to be applied from the cassette if you put more weight on the rear wheel). The center of mass is never static when you're riding on trails. It may be static if you're riding on the road or pathways.
  • 1 0
 @dominic54: smaller chainring does reduce performance tho
  • 2 1
 @deez-nucks: your COM will of course be higher while sitting in the saddle, but your COM only really matters while descending and that's when your seat (dropper post) should be down and out of the way
  • 1 0
 @2-1RacingUK: That's a good point. It might even out the load of descending a little bit. That's a bonus.
  • 2 0
 @deez-nucks: glass half-full; You also get to increase your dropper post by 10 mm as well.
  • 1 0
 @notai: smart point! Yes, your fully extended leg would require seat to be higher with pedal closer to you. Interesting...I think I will stick to my 175's I want max leverage at lower RPM's especially because 1 full pedal at the same gear ratio will still move your bike the same distance.
  • 2 0
 @deez-nucks: yes that will make the CoM higher yes, but please tell me where a higher or lower CoM is of a concern in climbing/riding along.
The art of the sport is very dynamic so, in reality these tests aren’t very relevant.

@pinkbike: you guys and girls need to develop a MTB/trail/downhill specific set of tests.
  • 1 0
 @notai: it is very noticeable. Think of it as a 20mm total difference in your level stance.
  • 1 0
 @notai: I've been on shorter and shorter cranks for the last 9 years. One interesting thing is that the top of the pedal stroke is double the crank difference lower, if your seat height above the bottom pedal is the same. On smooth climbs my seat is all the way up. On rough climbs I drop the seat a little and float off the back pushing the pedals more forward than down. The bike can bounce and it doesn't affect my power to the ground. And my knees are not over flexed because of the shorter cranks.
  • 1 0
 duplicate post
  • 28 0
 Also interesting how shorter cranks affect the rider’s stance during descents when pedals are relatively horizontal… maybe a really positive change for some to reduce this distance
  • 10 1
 this. harder to ride heals down with your stance spread further apart by long crank arms.
  • 3 0
 I wonder if I'd notice the crank lengths here as my feet can be man mm in any direction when riding flats. More than anything I wan the shorter cranks for less pedal strikes and lower BB options, everything else being relatively equal.
  • 19 0
 I feel the opposite specifically regarding when riding with cranks horizontal. I prefer to have a larger stance, for better fore/aft stability and balance.
  • 5 0
 @crazyrob: yeah I’m 6’2” on 175 and feel I might give up stability with cranks at 9/3:00 if I went shorter cranks, but for sure someone who’s 5’8” has a different sweet spot on stance
  • 6 0
 I've wondered about this, too. Dirt bike foot pegs are even with each other, so in theory really short cranks should approach that ideal while descending. Obviously they need to be long enough to still turn the pedals over, but I'm curious how something like 120-130mm would feel on a DH bike
  • 3 1
 @crazyrob: You don't feel like it's hard to lower your heal on the back foot? Without putting yourself too far back and having to "reach" with the forward leg?
Also, usually at the end of a long sustained downhill, one quad is on fire more than the other...having moved to shorter cranks and thus less separation seems to have helped that a bit.
  • 3 0
 @VtVolk: My thoughts exactly. Having a closer stance for the horizontal should make handling better. May even make holding a manual easier too.
  • 2 0
 I would think it’s better for you spine long term by making it easier to keep your hips square.
  • 6 0
 @RobertGrainier: motorcycles are super stable.
  • 1 0
 @nzandyb: yeah but some stability on pedals is achieved from actually shifting the plane of the cranks from directly horizontal on a bike… like you don’t just lock in at 9/3:00… that’s what I’m thinking when I say stability, absolutely open to seeing what 165 is like
  • 1 0
 @VtVolk: this an interesting idea, but I really think the sweet spot has got to be closer to 150-160… especially as bikes get longer, I think the weight difference to Moto means on bike you’re needing some of the lever length to compose things, weight does that for you in moto, I’m thinking
  • 1 0
 @alwaysOTB: wow, some serious reaching to justify buying new cranks. LOL
  • 2 0
 @ReformedRoadie: I'm 6'3" with a 36" inseam and size 15 feet. Years ago I had 165 diabolous cranks on my super 8 and I have ridden several sets of cranks in 170 and 175 on various bikes. Unless I was making a cross-country specific bike where clearance while pedaling was a concern, I prefer the longer length cranks for a more stable platform. I currently run 175's on my s6 Stumpy Evo and they feel natural to me, but I could see how running shorter cranks could offer some benefits while manualing, or to make a more nimble climber. Where I ride my climbs are pretty casual and a means to getting to the descents, so I'm not as concerned about pedal strikes. I do get quad burn on my back leg, but I just chalk that up with getting old Wink
  • 1 0
 Ask a slopestyler
  • 29 2
 86 people TOTAL were involved spread across these 7 studies. There needs to be a HUGE asterisk stating that this is a TINY sample size to try to extrapolate any usable data to apply to a larger group.
  • 10 1
 I feel like real life pedalling up a steep rocky climb would debunk the results of most of these experiments?
  • 5 0
 @50percentsure: There are so many variables to keep in check that even with a larger sample size, the results would apply only to someone riding a stationary bike.
  • 5 0
 @Spencermon: I don't think riding a stationary bike is even enough of a control because individuals will have their own athletic capacities. IE, maybe your cardio is good and your muscular strength is bad so spinning at high cadence is easier than mashing a hard gear, but also the opposite could be true. and yes, both those factors depend on genetics AND training. So your ideal crank length also depends on specific fitness/fatigue in the moment.
  • 3 0
 If you want more people in the studies then lobby your local politicians to fund more science. Sample sizes are small because it costs money, and scientists don’t get enough money to do everything. So you get away with the fewest “representative” cohort you can. And the “representative” cohort are typically students in the faculty.
But, in saying that, the studies aren’t claiming to find the right crank length for everyone, they’re measuring a subset of the population, the same subset who might benefit from the research.
  • 2 0
 @pasales: this is why they often normalise to VO2 max or similar.
  • 1 0
 @Mike-Jay: That's very true.
  • 1 0
 I think you're confusing physcology with engineering. Sample size isn't that important here, from what I gather they are comparative tests for the same bio-mechanical system with tweaks to the one variable. If Ford tested crank shaft left with 86 different engines I don't think they'd be any complaints.
  • 3 0
 @RichieNotRude: human physiology is so varied. 7 -16 people in a single study is kinda small when there is so much variety within the general population. Humans are very much different from engines. I'm skeptical as to how confident we can be in the results. Why would you say sample size isn't important?
  • 2 1
 @Spencermon: but this isn’t measuring the entire population or making claims for the entire population. Most of the studies are measuring trained cyclists and drawing conclusions for other trained cyclists. 7 is still pretty small, but it’s not as bad as you’d think.
(I submitted a paper with 3 participants once and a reviewer said that sample wasn’t big enough and we needed at least 4. So we got another participant. I’m not sure what makes 4 much better than 3, but 7 is almost double!)
  • 26 1
 I am 6'1" and have been riding 170 or 175 for a while; tried 165 for its supposed benefit of being farther away from the ground. Didn't notice significantly less pedal strikes, and also felt like my legs were turning in tiny, tiny circles. So back to 175 I went.
  • 22 3
 Ditto. 165 is amazing, right up until you actually put it on your bike and ride up any hill.
  • 7 4
 Use the right gears for proper cadence and power - that's what gears are for.
  • 11 0
 Im 6'4 and I have 165,170 and 175mm cranks on my bikes. Riding fireroad uphills there is zero difference for me, but I really the better ground clearance of the 165mm cranks. Technical climbing is much easier on the shorter cranks for me.
  • 4 0
 Ben Cathro runs 165mm cranks (which is what got me to try them but I'm tiny) and I'm sold (for my geared bike, still running 175mm on the SS because leverage)
  • 12 1
 @CSharp: Thats great on paper until I'm gassed. No matter has many times i tell my legs to spin at 90rpm they stay at 60rpm in the granny gear as im bouncing of the redline of my lungs and heart rate
  • 4 0
 I'm back to 175, after years of 165 and still not being used to it. 175 felt like coming home, even though I now have silver cranks on a black bike..
  • 3 1
 @Snowrydr01: Time to get in shape and strengthen those leg muscles! Big Grin . No seriously though, roadies always talk about cadences and this is why it's so important to keep certain cadences. Gears will do that for you but as well, you'll have to figure out which gear ratio works for you so that you conserve energy and use it when necessary. I run a 67% gear ratio as my lowest gear. Most bikes with 11 and 12 speed these days with a 28T chainring and 48-52T cassette is way lower than that (at 60%). If you use the granny gear 80-100% of the time, you're either doing your rides uphill or just spinning casually on bicycle paths. I've seen people ride trails and not change gears to adjust for terrains. It's an ineffective way to ride a bike since the gears are not being used to take advantage of momentum. A good example of this would be riding a rolling section where there'll be steep punch climbs and then dips in between. If you just kept using the granny on the steep up and then continue with the descent going into another punchy up, you'll get no power to get yourself up to the other crest because you'll be spinning like hell on the granny waiting for the bike to roll to the top of that crest. The bike becomes slower on each successive roll through. Regardless of which length of crank arms you have, this will happen. However, if you change gears to adjust for cadence, that energy converts to momentum to carry you through the curves with less effort. Talk to guys who ride singlespeed hardtails. Wink Their gear ratio is > 100% but they know when to crank things up without breaking the chain or the rear hub!
  • 5 0
 @dolface: Leverage is only there to break the chain or the rear hub Wink
  • 2 0
 @CSharp: Obviously in "trail mode" im shifting around. i meant on the 10+ minute sustained climbs a couple hours into rides. Ive been so dead im at 40rpm fighting for each stroke. There no willing my legs to spin faster (although i know i should be) at that point. Any less than a 170 crank and im walking. Im no XC star but i am riding 2-3 times a week and on zwift 2 times a week. Sometimes you just run out of gas, and i need all the leverage i can just to keep climbing.
  • 7 0
 There's a few things missed in the article, one of which is the hubs poe, if shorter cranks necessitate a smaller chainring, then you are looking at a larger rotation of the crank to engage the hub, the main benefit of a high poe hub is for climbing, the ability to apply power with smaller crank rotations equals less pedal strikes, getting back on the power quicker. Longer cranks also allow you to have the seat lower so when your cranks are in the mid position you have more movement off the saddle. So longer cranks should be better for technical climbing. But... with modern bikes, hub poe has increased, trails have also changed for most people, with much more emphasis on gravity and flow trails, with easy climbs back up at bike parks, for this type of riding, fire trails up, standing up down, then the benefits of shorter cranks would make more sense for the reduced rom for pedalling while standing. I don't personally buy the pedal strike thing while descending as cranks will likely be horizontal, which removes the cranks length from the equation.
  • 1 0
 @hubertje-ryu: how tall are you bud?
  • 4 0
 I'm a leggy 6'5, and I've ridden 170, 175, and 180. I did not like the 170 at all, even after a couple months. 180 felt great, but I switched to a better (1x) 175 crank and am okay with it.
Technically my first mountain bike came with 170/175 arms. It had been a rental and must have been repaired at some point.
  • 2 0
 @Snowrydr01: You sound way fitter than I am. However, there are certain aspects of setting up the seat if you go with different length cranksets. I was setting up my seat after tearing down my bike for cleaning and regreasing. For most of the rides prior to last season, I had my seat set up perfectly for climbing and descents. Then, for some stupid reason, I decided to put my seat way back probably to get a bit more slack since I put on a really short stem. For that whole last season and into the beginning of this season, I was really struggling on the climbs. Then someone mentioned that the body position should be more direct in line with the bottom bracket. So, I went to check my seat and moved my seat forward and backwards until I found my sweat spot again (took about 3 rides up big climbs). That made a huge difference. Also, on some of the rolling sections where my dropper post goes up and down constantly and then to do a long climb after that, I noticed that sometimes my dropper is not grabbing on fully and my weight forces the dropper post to go down by as much as 5-10mm, my legs would really feel it. But once I get the seat back to the optimal height, my climbing power goes back up. Spinning with the knees bent more, the quads seem to tire way faster. So, changing out the crank arm length might alter more than one area of position on your bike. Anything you change out, you'll need to recheck the measurements and retest until you find your sweet spot.
  • 2 0
 @dockboy: I'd run 180 if I could find any good cranks in that length.
  • 1 2
 @ctd07: so shorter cranks -> smaller chainring -> less pedal kickback -> better suspension?! Sounds like another win unless you ride trials!
  • 1 0
 Exactly, 165mm cranks on my dh bike were the worst thing about riding it uphill, at least with my 34" inseam. Those with shorter legs may disagree.
  • 1 0
 @DG370: 184 cm, 6 ft, long upper legs, very short lower legs.
  • 1 0
 @Altron5000: so many bikes have excessive kickback these days because designers emphasize ridiculous amounts of anti squat, this is fine if you ride clips, but crap if you ride flat pedals.
Bikes like the old Giant Reigns were great, NS are pretty dialled on KB and AS these days. (to name a couple).

@CSharp totally agree, the newer steeper STA are the biggest power adder in climbs (especially for us taller guys), 77 should be the absolute minimum these days.
  • 1 0
 @Altron5000: a smaller chainring will usually increase the pedal kickback.
  • 1 0
 My CX/Gravel bike came with 170mm cranks (but I didn't know this) and when out on gravel rides and climbing hills something didn't seem right. It felt like I was putting the power down but it didn't feel like power was getting delivered and going up hill seemed abnormally hard. Eventually I found out they were 170mm cranks and had an "OHH" moment. I replaced them with 175mm cranks and climbing on it was much better.

Since we are XC in our parts I'll stay with 175mm cranks as I really hated running 170mm. Oddly 172.5 on my road bikes feels completely normal.
  • 3 0
 @zephxiii: My cx bike has 180mm arms on it. I've tried 170 and 175, too, but the 180s just felt so good. Any time I switch I can't get back to feeling normal.

I once borrowed a road bike for a summer that had 225mm arms on it, along with all sorts of weird geometry choices - this guy pioneered long and slack - but that was a wild machine, outside the bounds of standard bike design rules.
  • 1 0
 @dockboy: Try riding with an aero tuck with those long crankset Big Grin
  • 24 0
 Interesting stuff, but always maintain some skepticism about the conclusions of research having only a few participants. Studies making conclusions with only 7 people can't be applied to the whole population...you get 700 people in your study, well, that gets more convincing.
  • 6 5
 Since we can't even agree about how many people have died of vivid with a sample size of billions, the chances of agreeing a perfect crank length seem slim at best!
  • 17 1
 @jaame: If people would stop politicizing drivetrains we'd all agree that the microchipped left cranks who favor free cadence monitoring would like to release all the freehubs from traditional driveside incarceration.
  • 22 0
 @jaame: In the United States half the country would be on 120mm cranks and the other half on 220mm cranks.
  • 3 1
 @nzandyb: Too true! Good one!
  • 1 0
 Agreed. I think this was a really good article with a lot of good things to think about. But not long ago didn't Giant pretty much have themselves convinced that 29" wheels didn't make any sense over 27.5? Some "research" must have been done there...

Moot point for me though. I have extremely long legs and I'm on a mulleted Kona process. I would kill to get the seat forward a few mm at full height on steep climbs. Going shorter on crank arms for me and needing to raise the seat (and moving it back) are a no-go here. I don't see anyone mentioned that point.
  • 23 7
 I get the sense from this quote that Seb is conflating torque with horsepower (torque over time).

"Power is just force times speed or torque times rotational speed, so either way, the power is the same (at least in theory). It's well-documented that riders naturally pedal at a higher rpm when using shorter cranks; so to some extent, the reduced torque is compensated by a higher cadence."

Increased torque improves acceleration from lower speeds, such as when getting up to speed after exiting a sharp corner. Horsepower (torque over time) is most beneficial when you are already up to speed, which in our case, means sprinting.

So the question I think riders need to ask themselves when it comes to choosing a crank length, is whether more torque or more horsepower is most beneficial to your musculature and riding strengths and weaknesses. Also, how sharp are the corners on your local trails? If you have a lot of switchbacks, longer cranks are probably the answer while flow trails will favor shorter cranks.
  • 10 1
 Not really.
You'd adjust your chainring size or gear selection, thus same power = same speed at rear wheel and same torque at rear wheel = no changes.
  • 9 2
 I see what you’re getting at but you’re misunderstanding how power and torque work to create a driving force at the ground via the chainring, chain, sprockets and rear wheel/tyre. With shorter cranks you pedal with higher cadence, so you’re using a lower gear ratio for a given speed. At the BB longer cranks have equal power via increased torque but decreased RPM but at the rear hub the gearing modifies that torque x RPM combo to match the wheel speed, so the torque is the same as with shorter cranks.

The only benefits I’ve found with long cranks are the lower saddle height if you’re doing anything technical seated and the lower foot position when cornering with the outside pedal down on a bike with a higher BB. So I guess they have their place on older bikes with high BBs and no dropper post. But on modern bikes shorter cranks are usually better.
  • 2 1
 Not right amigo - HP is the only meaningful figure at the 'crank' (rider or engine) when gears are involved and has absolutely nothing to do with acceleration vs speed. Rear wheel torque or 'tractive effort' (for heavy machines and trains) is used to extrapolate how this HP is translated into functional movement based on transmitting (mechanical, electrical or hydraulic) to a wheel or track, taking into account losses and in the case of wheels, the diameter and corresponding leverage....

Torque figures can certainly allude to how the engine will respond and it's nature, but in and of itself, largely meaningless without the RPM component...aka HP and/or Watts...
  • 1 0
 @faul: and with the added benefit of negating any additional torque that longer legs can provide. Win - win!
  • 1 0
 @RadBartTaylor: I get what you are saying on a mechanical level, and you are right. So, in essence, I think the main question to be asked is what cadence and pedaling circle diameter is the rider most biomechanically comfortable? I suspect that a fast twitch muscle biased rider and/or a tall rider might benefit from longer cranks and the converse is also true for slow twitch and/or shorter riders. I guess what I meant by the torque vs HP comment is referring to the motor itself (the rider) and what biomechanically works best for them. Similarly, a tall rider has a harder time getting around switchbacks and has a slower exit speed, so a crank length that allows them to put down as many watts as possible as quickly as possible will be more beneficial than the opposite. Makes sense?
  • 1 0
 @ShopMechanic: yeah, makes sense to me! Good point on coming out of corners....I
  • 17 2
 The science concluded :"Pick your crank length and be a dick about it" and " 175 ain't dead".

Marketing concluded : " if we convince everyone shorter cranks are better we can sell new cranks to lots of folks, how about we change the pedal eye diameter as well?"
  • 12 0
 every time i think road cyclists are the most gullible twits on the planet, ready to accept marketing bullshit as science and progress, i remember that mountain bikers exist. no group has accepted more compromises and failed engineering as beneficial in the history of the galaxy. capitalism!
  • 2 0
 They can't sell anything to anyone right now, because they can't make it fast enough!
  • 2 0
 @Villgaxx: why do you hate Fox so much?
  • 4 1
 Will short cranks bring back 27.5? With recommended lower gear ratio average speeds should drop back down, making 29 overkill. Then, with smaller wheels we wouldn’t need huge $500 cassettes anymore and could go back to decent chainline and light, 10-46 10sp cassettes for $150.
This is gonna be sick. I’ll gladly kiss my calf muscles goodbye for a few more 27.5 options.
  • 3 0
 @emptybe-er: wrong the shorter cranks are the next step to 32s. Need the shorter cranks to prevent heel rub on those 2.6 inch 32ers and the 75 tooth casette on the new SRAM Condor 1x21 speed.
  • 14 0
 As a tall rider, anything that raises my saddle height further is annoying. Yes, you can maybe offset it with a longer dropper for descending, but for seated pedaling it's got drawbacks (increased saddle to bar height, or increased stack removing front wheel pressure). I also think that shorter cranks tend to shift muscle utilization away from slow twitch muscles (surprised there wasn't a study on that?) and towards fast twitch which to me is a negative for anything marathon / XC related. So for me, I use whatever the frame was designed around, and I'm perfectly happy with 175s for XC and 170s on my big bike.
  • 1 0
 Agree - this is the key downside for taller riders. That extra 5mm seat height more than offsets any gain on descents from having shorter cranks.
  • 15 2
 I had cranks too long at 175mm, and dropped to 165mm and it was one of the most noticeable upgrades I have ever done to my bike, The number of pedal strikes I get is almost non-existent by comparison to the old cranks. The other advantage is my feet are 2 cm closer together when standing level on the pedals for the fun times.
  • 15 0
 I like big cranks and I cannot lie.
  • 11 0
 Mike McCalla (former WC pro) tested this too, in an issue of Mountain Flyer a few years back. He found no meaningful differences.

The thing is, there's a reason we're all on pretty long cranks - back in the days before droppers, if you ran 150 cranks, you had to raise your saddle 25mm to compensate, which is... bad for descending, to say the least. Any advantages you get from being able to run a lower BB height are negated by the saddle being jammed up your butt.

With droppers, different story. I spent a few years trying to talk people into shorter cranks (Canfield makes some nice ones down to 150mm or so) but it was just too weird for people to wrap their brains around. If some big company (ie Trek/Specialized) decided to push it it could take off, maybe.

-Walt
  • 12 2
 As a 5'7" rider on 175mm cranks... I'm DEFINITELY going shorter with my next pair. I can have my saddle as high as I can take it with a pedal down, but still be crouched on my other leg, it just feels exhausting.
Canfield make a crank set that goes down to 150mm - I'll be getting the 155s!
they are standard amongst e-bikes where there is assistance, but i think they have more use than that.
  • 2 0
 Do it. I'm 5'8" and going down to 165mm has been great, I'd go down further in a heartbeat if it was possible/easy to get cranks.
Slight hassle getting low enough gears as mentioned. I got an old Deore XT crank at 165mm then machined the small bolt circle back to get it in aligment with the middle ring and an Absolute Black 26tooth oval with a 9-42 cassette in the back. Saves a surprising amount of weight, lots of which is unsprung, big increase in ground clearance and happy knees.
Shorter cranks also save weight.
I'm pretty sure the "right" answer is for cranks to be proportional to leg length.
  • 8 1
 I am same height as you, Canfield 155's have been one of the best upgrades I have ever done... Just know that you will likely want to go down a chainring size, as the perceived effort definitely does go up.
  • 1 0
 155s in the post! 177cm rider with short legs, 165s have been an improvement over 175s. Sticking w/30t ring since I was considering going up in chainring size on current 165 setup.
  • 2 0
 @BigHerm: How do you guys deal with the gearing?
  • 7 1
 We're here for you!
  • 3 0
 5'10" here. I have a set of 155 cranks sat in a box, waiting for a frame with a geometry to suit to hang them on. I don't care about avoiding pedal strikes so much; I want a lower BB with the same clearance
  • 1 0
 @DirkMcClerkin: not sure I know what you mean? Stock setup was 175 carbon w/34t, upgraded to al 165 w/32t, then 30t for SoCal fireroad climbs. 30t has been feeling a little easy lately hence my thoughts about going up in ring size.
  • 1 0
 @canfieldbikes: I'm 5' 7.5" with a 29 inch inseam in pants. Not sure what my "cycling inseam" is as I think it's measured different. Loved my 165s but want to go shorter. What's the min crank length most riders with my dimensions feel comfy at? Thanks!
  • 1 0
 @Nwilkes: there's not one right answer that works for everyone, even people of similar height/proportions. Lots of personal preference and bike setup, riding style, terrain, etc. all play a factor. We have customers over 6 foot running 165s. You could probably do 160 at your height. 155 would be a fairly noticeable jump.
  • 15 5
 Each study focused on cycling (aka road biking) where speed of cadence is supposedly king. However, RPM is only one part of the power equation, with torque being the other. Trying to spin 130 rpm on a mountain bike trail not only looks ridiculous, but it throws you off balance and gives you a greater chance to pedal strike. By getting into a slightly harder gear it will slow your rotation down (ideally 40 or 60 RPM) and will give you the same effective overall power, while increasing your stability to get over obstacles, and also decreasing your chance of pedal strikes. (Ratcheting is still a thing, right?)

I personally would like to see tailored cranks depending on bike size, ie 165MM cranks on small and medium bikes, and like 175MM cranks on large and xlarge bikes.
  • 3 1
 That's a bingo!
  • 11 0
 Your numbers here are so far off. 175mm cranks with cadence of 80 rpm gives the same power as 165mm cranks with a cadence of 85 rpm. To travel at the same speed at 130 rpm as at 50 rpm you need to shift from a 50 tooth rear sprocket to a 19 tooth sprocket. That’s like changing from the lowest gear on a 12 speed cassette to the middle gear. This is not a slightly harder gear, it’s a massively harder gear.
  • 2 1
 Another thing I noticed when I was training on the road bike was the contrast between standing up pedalling slowly in a higher hear or sitting and spinning high revs in a lower gear. For an approximately equal road speed, the heart rate was a lot higher for the seated/high cadence method.
A friend of mine surmised that the glycogen would be depleted more quickly when stand up pedalling, buy could never back it up with research.
  • 2 0
 So you are normalizing for torque production, but pedaling harder by applying more force @ same RPM on shorter crank = same power...this gets into the biodynamic component of the human body and how it responds to RPM vs force.

I understand what you are saying but think your RPM numbers are a bit off making that comparison (130 vs 40-60)
  • 6 0
 @jaame: I'm no expert but the high rpm seated style, which kinda started with Lance, does take some training to adjust too. We kinda saw this back in the early 2000's, two extremes, standing while pedaling at like 40 rpm in the big ring (Marco P) vs seated spinning like a madman (Lance A)....I think it comes down to training and body type.

I think us MTB'ers generally do better at slow RPM simply due to the nature of most of our climbing.
  • 3 1
 Trek does this. I 'warrantied' my 2020 Checkpoint SL6 because it came with 175mm crank and the spec sheet had 172.5mm... Being that I'm 5'9'' this makes more difference than you'd think and for several hours of cranking on gravel it's surprisingly harder on the knees, hamstrings and back... ideally I would have got a lot shorter again though (the cranks, not my height).
  • 12 0
 My 170mm NX cranks lovingly polished by heel rub say “you weren’t going to buy new cranks anyway you cheap bastard”
  • 3 0
 I like that image
  • 7 2
 Our cranks feature raised, polished external ribbing to prevent heal rub/wear. Wink
  • 2 1
 @canfieldbikes: Won't your heels just rub the raised ribbing though?
  • 1 0
 @warmerdamj: yes, your shoes will rub the ribbing (which is already raw aluminum), so they won't wear off the anodizing on the crank arms (let's face it, it just doesn't look good to see cranks with the finish rubbed off on a nice bike). The ribbing its subtle and has smooth, rounded edges so it won't snag or tear your shoes.
  • 10 0
 My takeaway from the article. Next time someone asks me why I run a 30t chainring, I am going say it is to match my 165mm cranks, instead of admitting I am using 175mm cranks and need the shorter gearing.
  • 5 0
 Nothing to be ashamed of. I use 28t with 175mm, but this just means that I keep riding when everybody else is walking.
  • 3 1
 26t here, XT 10-51. I like to sit and spin so I have the endurance for long rides. I can always drop a gear or two to crank over obstacles. I keep trying to talk my younger riding buddies into gearing down, but they're stubborn like that Wink

I'm always the last one to walk because I can clamber over obstacles so much easier with stump pulling gears and short cranks.
  • 3 1
 @nurseben: your buddies walk first but they probably also get over the section faster than you.. at 30-50 or lower , walking is both easier and faster
  • 1 1
 @GZMS: actually Inot only out clean them but I’m faster than them too, partly it’s fitness and partly it’s skill.

For tech climbing, tall gears don’t help much, but having a deeper lie range can be helpful.

I ride a lot of rock, Hurricane, GJ, Moab, etc … plus my home trails around Tahoe, very few folks can pace me through tech up or down.

… and I ride short cranks and a tiny chainring Smile
  • 7 0
 @nurseben: lol 26x51, that's going nowhere fast.
  • 1 0
 @GZMS: I have the same impression as nurseben. People with a similar level of fitness will arrive at the top later than me just because they had to dismount several times. Also spinning at 28 x 50 is faster than walking up a steep road, give it a try.
  • 1 0
 I see your 30t chainring and raise you 28t, with 165mm cranks. My cassette only goes up to 46t so it's what I need to be able to pedal up steep stuff.
  • 1 0
 @Konyp: i tried it many times during XCM races.. walking is faster, especially on technical sections.. ofc if you are walking like in the park, or it is only a few meters, then maybe not.. but if your pedaling is at around threshold, and then you walk also at around threshold HR pace, then it will be faster
  • 2 0
 @GZMS: Yes, sometimes walking is faster, but I don't ride a mountain bike so I have to walk ...
  • 13 0
 Conclusion: Inconclusive
  • 8 0
 I'm 6'4" and I've been running 160mm canfield cranks, felt like I was riding a monkey bike the first ride but now i'm used to it.

Anyone struggling to find 165 sram cranks should take a look at canfield.

canfieldbikes.com/products/canfield-bikes-am-dh-cranks
  • 2 0
 I've tried even 170's and can't stand them. I tried for several weeks, I am also tall with an 85 cm seat height. I have had in the past bicycles with 180 mm cranks, and I loved them.
  • 8 1
 Glad you are loving our cranks!
  • 1 0
 @canfieldbikes: We love Canfield Smile
  • 9 1
 I've tested several length cranks on my own bike. At 5'10" with long legs 170s offer the best feel and provide some notable advantages. In fact it was a notable improvement right away.
I'd also add that if I had to choose between 165s or 175s, I'd take the 175s as considerably better. 165s felt REALLY odd to me and negatively effected me on the climbs. I get that the power was still there. It just felt like my femur was too long or something on 165s.
A few other notes: The raised seat height from going to shorter cranks is a real thing and can effect your entire bike set up. Handlebar height and so on. Also unless your sta is 90', it's not a 1:1 relationship between seat height & crank length. More like a 4 seat height : 5 crank length ratio.
On my wife's bike I just defaulted to 165s (she is 5'4") as she is unlikely to provide any meaningful feedback. My 9 year old daughter is on 152 cranks.
There is a serious shortage of quality crank offerings at different lengths. However Rotor makes a killer XC/ light trail use 165mm crank.
Lastly, after we get this CS length to be size specific the bike designers need to work on BB height and use a lower BB on smaller sized bikes so that when a smaller rider is standing on 160-165mm cranks their center of gravity and pedal clearance is similar to a rider on an XL riding 175 cranks. This just makes sense.
Also going to add that higher pedal cadence is VERY helpful. It's simple math. Torque x RPM = Power. You can provide the exact same torque through the pedals at a higher rpm and have much more power to the rear wheel. Figuring this out was a game changer for me.
  • 4 0
 It's not really "helpful" to spin faster, it's just putting out more power. It's not like you get that extra power for free. You literally have to put out more watts to spin faster.
  • 3 0
 @SunsPSD I totally agree, especially for taller riders, effective seatpost angle means the 10mm difference in seated height going from 175 > 165 really messes things up.
  • 1 0
 These guys make some pretty cool looking and customizable cranks down to 155mm.

www.ignitecomponents.com/product-page/mtn-cranks-pre-order
  • 2 0
 Hope today you will figure out that you havent figured it out before..
  • 1 0
 I thought I was the only one. I am really not picky between 170, 172.5, and 175's, but I really noticed a diminished ride satisfaction with 165's. That being said, I am striking a lot with my 175's, so may go down to 170's next bike.
  • 4 0
 You can’t put the same torque because your lever arm has shortened while the force remains constant,
  • 2 0
 @DG370: Ding ding ding. The absolute number one reason why this doesn't make sense for riders with long legs who are already maxing out 200mm+ droppers
  • 11 4
 Ok, so to sum up, shorter cranks require easier gears, so if you find yourself using the easiest gear, there are not for you (if you happen to use 30T on your 29er, yes you are f*ked). Also, you should buy a new dropper post, cause your saddle will be 1cm higher. In return you get a bit more clearance when pedalling on flat rocks. And with my 88 inseam and 180cm height I need a 180cm crank. So to sum up, sizing from 175 to 165 cranks for me is a total nonsense. But I get it, there are no downsides to shorter cranks Smile
  • 8 0
 Haha so true. Put some of the experimenters above on a 165mm cranked 29er with a 10-50 cassette and hit an hour long ratchet steep climb... see if they can notice the subtle esoteric difference of walking the entire way.
  • 1 0
 You’re looking at it all wrong. You don’t have to buy a new chainring and dropper, you get to buy a new chainring and dropper!
  • 1 0
 No, you just need to pedal a tad faster, and you will lose only a bit of leverage.
Then you just slide your seatpost 1cm higher and it's solved.
You need 180cm cranks? What are you, a giraffe ?

Maybe it's not for you, but not for any of the reasons you listed
  • 8 1
 Ok I’m tall with long legs so I’m bias, so take this with a grain of salt. Here are a couple of negatives I’ve found with shorter cranks.

1. You have to ride at a higher cadence. Let’s say you up you cadence 5 revaluations per minute, on a hour climb that’s 300 more pedal strokes you have to watch out for and have less torque if you need to stop pedaling and restart pedaling. If you need to take a partial pedal stroke I would argue that low end torque is more beneficial.

This also adds up if you are sprinting down hill but to less of a extent, but with much higher consequences. Hitting a crank when climbing is annoying, clipping a crank in a dh race is another thing entirely.

2. You raise your center of gravity, by the length of your crank when seated and by a touch when standing. Seated is normally at slower speeds so less important but more stability when trying to clean a awkward climb isn’t a bad thing and a lower center of gravity going down is typically better.

3. Less stable and possibly harder to get lower when descending. If your feet are closer together you are less stable, your center of gravity is higher. A wider stance also makes it easier to get lower (I would think most people can get tower to the ground doing a split squat vs a regular squat).

4. I would think on a 160 travel bike dynamic ride height and mid stroke support play more of a role in pedal clearance then 5-10mm of crank length. Not to mention the higher your seat the more leverage you have on you suspension so you could theoretically cause more suspension bob especially if you bike has a stacker actual seatube angle.

5. If you need to gear down this could also effect how your bike pedals, this good go ether way but something to think about.

Im not saying everyone should ride longer cranks but that there is more to it than just static pedal clearance. Mountain biking is a very dynamic and there are trade offs to both.
  • 4 1
 @rich207 3. Less stable and possibly harder to get lower when descending. If your feet are closer together you are less stable, your center of gravity is higher. A wider stance also makes it easier to get lower (I would think most people can get tower to the ground doing a split squat vs a regular squat)

You know when I had 170's on my 150 mm stump jumper I really felt this. I was just not feeling as low and stable. Switched to 175's and it felt completely different, while only adding 1 cm of distance, strange but true.
  • 7 0
 It seems like TdF riders, with their million dollar contracts and teams of in-house performance experts, would have thus figured out right?

Why do they basically all run 170-175mm cranks? Jan Ulrixh famously ran 180s, fwiw.
  • 3 3
 Because on a road bike there is no significant downside to longer cranks.

The studies above show not that short cranks give more power, but that they don't give less power.

On a mountain bike you get benefits from shorter cranks in increased ground clearance and less rock strikes. On a road bike that doesn't matter so riders can go with A: What they are used to and B: What their sponsors actually make without any negative effect.
  • 1 0
 @Patrick9-32: Seems like sprinters MIGHT benefit from shorter cranks. You'd think they'd have tried already though, and they don't seem to be (Cav rides 170mm apparently).
  • 7 0
 I like that there's a section "What about for mountain bikers?" - as if "mountain bikers" would have different physiology to other humans. Note that the study was done with "mountain bikers", but was NOT done while "mountain bikING".

Just like the other studies it looked at fixed cadence riding, time to peak sprint power, and maximum sustained power output. This doesn't seem to be to be a particularly good model of technical trail riding - I for one don't spend much time 'spinning' freely, at least not at the moments when it feels like it really counts. At those moments I need peak instantaneous torque, not power, and I'm unlikely to be putting in full pedal rotations. Using different gearing to enable to to attain the same peak torque at the same leg speed and force on the pedal may not actually be practical if my pedal ends up at the 6 o'clock position instead of 4 o'clock right when I need maximum clearance.

An interesting corollary is studies of pedalling efficiency on the road - multiple studies have shown no significant difference in overall efficiency between flats and clips. Like each of the studies above, it's a convoluted demonstration of the laws of conservation of energy. At the end of the day the determinants of power output are the rider's lactate threshold/FTP/VO2max, not the crank length or type of pedal they are using; energy in = energy out. However, just because different pedals or crank lengths don't magically alter your overall physiological performance, it doesn't mean they don't have advantages in particular situations.
  • 10 0
 164.99 Crank lengths coming soon...
  • 15 9
 I ride 155mm on my GG Shred and my Canfield Tilt, 160mm on a Canfield N9. I like short cranks, started riding short cranks on muni, rode down to 75mm, but my preferred muni length was 150mm, so no surprise I prefer that length on a bike. Canfield recently added a 150mm crank length, which is the direction I'll go if I need cranks. It's funny how stuck some folks get on certain standards, I tend to be curious about new things, so I'm always open to change. To each their own. I've made a few converts to short cranks, all my riding buddies sized down to 165mm cranks and they don't notice any disadvantages, but they really appreciate the added pedal clearance.
  • 8 11
 Why would anyone downvote my comment?

I mean dang,! Here's a guy (me) who rides hard, has been riding for forty years, is an experienced mechanic, rides muni, tandem, SS, Fat, FS, has ridden a huge variety of crank lengths (75-180mm), and I get downvoted. Is that wierd of what?

Sometimes I get this sense that up and down votes are more about some personal antagonism toward the poster than it is the content of a comment.

Pinkbike used to be more than that, at least it seemed that way back in the day.

So sad.

At least I don't care anymore Smile
  • 5 0
 @nurseben: 75mm cranks??? Did you take them off a kids bike?
  • 3 2
 @audeo03: Unicycle dude, MUNI.
  • 10 0
 @nurseben: Oh. I though Muni meant municipal, like city riding/commuting...
  • 3 1
 @audeo03: Mountain Unicycle, the best thing ever, super hard but very rewarding, but damn it takes a while to get good. In my hey day I rode Moab, GJ, Hurricane, etc...

You should try it!
  • 3 0
 @nurseben: LOL, I wouldn't care about the up or down voting. I think a lot of people think they know physics when they actually don't. I've been riding 165mm cranks for a good 25 years and I can ride trails just as good as anyone I ride with. 99.9% of the people I come across usually have stock 170-175mm cranksets. More than half of them probably don't care or don't know their specs. For those who know their bike specs, they'll tell you they need longer crank arms for more leverages on steep climbs. However, on those same steep climbs and especially on those technical rocky and rooty climbs, I'm either right there with them or I'm climbing all the way clearing sections with my 165mm cranksets. Beginning of the season, I'll be one of the worst climbers but by mid-season to the end, I'll be right there with everyone (either that or they're trying to not make me look bad Big Grin ).
  • 4 2
 Hilarious how pedal strikes are somehow the crank length's fault. Aren't you supposed to look where you're riding?
  • 3 0
 @CSharp: but obviously you know your physics. LOL
  • 4 1
 @Old-Guy: you must not ride much tech, there are places where pedal strikes are a real problem, a solid hit could break a pedal or send a rider flying.

Sure, good skilz are important, but being able to clear a rock by an additional 1/2” can be the difference between walking and riding.

So yeah, long cranks are probably fine for what you ride Wink
  • 2 1
 @Old-Guy: If you can look at every little rock and root then you're probably not going quick enough.
  • 8 1
 According to Science every single thing in this article needs to be thrown out. 10ish people per study means a confidence level of about zero. Just saying, according to science, absolutely no useful data was gained.
  • 2 1
 No, that's not how statistical method works. Depending on the magnitude of the effect you want to measure, a sample size of 10 per group in a crossover study may be perfectly adequate.

Read the "Factors influencing power" [statistical power, not watts/kg!] section on wikipedia.
en.wikipedia.org/wiki/Power_of_a_test
  • 1 1
 I think your all confusing mechanics with physcology, do Ford use a sample size of 10000's when testing their crank shafts ?
The scientists/engineers have measurable mathematical inputs and are testing with pretty small set of variables in the grand scheme of things. The fact that the mechanics are bio doesn't make that much difference in my eyes.
  • 6 0
 Im 4 foot three and currently riding 190mm cranks...I love the stability it offers but I want to beable to get more leg drive so thinking of down sizing to more like 185...
After reading this article I'm still not sure...
What does everyone suggest?
  • 2 0
 Can't upvote this enough
  • 6 0
 What about pedal thickness? Since we´re talking about 5mm differences we need to compare a thin flat pedal with a bulky clipless one (and all the stack added by the cleat and retention mechanism). For instance, a rider that uses a shimano spd pedal will have a much shorter perceived crank lenght when comparing thin flat pedal vans shoe rider. But the flat rider would have a lower perceived bb height. Ppl talk a lot about 3mm bb drop differences but rarely mentions that a 3mm thiner pedals will give kinda same results.
  • 1 0
 I have this idea of an offset pedal with one side sat in with the platform for the shoe past the center of the pedal's axis fixture to the crank. Sorry for the bad technical explanation, but I think you get what I mean. The bottom of the pedal can be round without things sticking out because they have to be able to fit a shoe on the other side. Hell, it could even be made rugged, with a smooth sliding surface, and even have a thin layer of damping on the bottom to be able to smash into and slide off things! But some kind of mechanism, electronic or not, would have to be built in making the pedal always face right side up. Don't know but maybe those mechanical engineers could make use of some phenomenon to make this happen. Of course there are a number of things that can go wrong with this kind of a pedal, but I think it's a great idea that would solve a lot of problems while actually riding with the feet on the pedals. Worst thing about it it would induce a new larger pedal thread diameter to the cranks.
  • 9 2
 Let me guess... none of these studies factor in that a lower cadence/more torque allows for improved use of your legs as suspension.
  • 15 2
 Word up. Having constant back pressure on your pedals is a need not a want when you have to float 1/2" above the saddle pedaling through rough janky garbage. There are so many benefits to lower cadence and higher torque when you're doing technical/awkward bike handling, especially technical climbing. And nobody mentioned the downside of having your ass an extra 10mm in the air in low speed situations.

It's a great article citing great original research, but I think the takeaways are more for the road/gravel/smooth XC crowd and for people doing pure winch and plummet laps on logging roads. For riding on actual trails, I'll keep my long crank arms and low saddle, thank you.
  • 7 0
 @TEAM-ROBOT: The interwebs could use more of your colorful pragmatism.
  • 2 3
 @TEAM-ROBOT: Does a dropper post not negate most of the 10mm your ass is in the air? not to mention you have 10mm more clearance to lower you body since the upper leg is lower.

And less pedal strikes on janky, rocky climbs. (add to that more chainring clearance if you go smaller there)
I get the idea of ratcheting to avoid pedal strikes - looking at you Seb Kemp - but having more clearance either with crank or BB height frees up bandwidth to nail all of the other things you're focusing on...

The answer is more squats and kettle bell swings to get the required power with a slightly shorter lever. Wink
  • 3 0
 @ReformedRoadie: A dropper post does allow you to drop the saddle 10mm, but with shorter cranks you're dropping it from a higher starting point. I drop my saddle 10-20mm in truly technical pedaling situations with 175mm cranks, so the only thing that would be different with shorter cranks is that my seat would start higher and end higher when I dropped it. Said differently, shorter cranks will always mean a higher COG for seated pedaling, because you're not going to reduce your leg extension, so your seat is always going to go up to compensate for your bottom foot being higher.
  • 2 0
 @TEAM-ROBOT: I do the same. The shorter crank will also allow you to drop a bit more, since the top of the stroke will not be as awkward with a shorter crank.
In cases where getting your center of gravity low really matter, we're going to have the seat fully dropped.
I just think the benefits out weigh the costs...for some, there might not be any. Whatever works for you...

We might disagree on this point. But damn, you seem pretty knowledgeable. You should consider maybe doing a Q&A column or something...

I think we agree on LEGOS.
  • 2 0
 @ReformedRoadie: Thanks for the kind words. And you're right, I love Legos.
  • 8 2
 We're big believers in the benefits of shorter cranks and have been for years! We make AM/DH rated cranks all the way down to 150mm. canfieldbikes.com/products/canfield-bikes-am-dh-cranks
  • 3 0
 Amen boys. I switched to 155’s on my scout and I love them. Have a new pair waiting for my patrol frame when I get that too!
  • 2 0
 What's a cheap chainring I can run with these that isn't $70? It seems hard to find 0mm offset SRAM chainrings. I'm between:
160mm Your cranks + $70 chainring = ~$300
165mm Raceface cranks + $20 chainring = ~$150
Hard to justify double the price for 5mm, and I just want a bombproof steel chainring.
  • 5 0
 I'm 190cm tall with long legs.
I have been interested in this topic for years, and have ridden from 165mm to 190mm.
165mm gives me knee pain, with i don't have with 180mm (which you can find from Shimano and sram)

For my 165mm cranked Bosh eBike, i bought some 170mm and 175mm to test them out.
  • 2 0
 I am 180cm and it's same for me. Anything less then 170mm I have knee pain.
  • 2 0
 I've run 165-175, at 187cm tall. I really didn't like the 165's, and that was on a dirt jumper. I liked 170's best on the dirt jumper. And 175's on my 26" full suspension bikes. 170mm felt short. I don't know what I've got on my Kona Satori DL, size L, but no complaints on that. Would be interesting if it is a 170mm instead of a 175mm.
  • 5 0
 The hole burning through my wallet as I read this article magically closed back up when I ran the numbers. At 6'3", the math says a perfect crank length is 175.26mm. All my cranks are 175. Woot! Onto the next hyped up thing.
  • 4 0
 So the article title says shorter cranks are better but the conclusion across the research is that it doesn't make a difference. It seems the main benefit is ground clearance and that depends highly on type of bike, terrain and riding style. What's disappointing is that only one study took physiology into consideration and even that was only at total leg length. So that leaves a huge amount of data unaccounted for. There'd need to be a fairly large multivariate study done to be able to say with any sort of certainty what type of difference crank length makes across different disciplines of riding.

It seems to only notable conclusion is that if you ride long/slack/low bikes then shorter cranks are a plus.
  • 4 0
 @seb-stott: Lennard Zinn at your sister publication VeloNews did several articles on crank length many years ago--you should research their archives.

I'm not sure they were able to measure power at the time, but my memory says they came to the same sort of mild conclusions about crank length: there just isn't a huge difference in efficiency between sizes. Their shortest tester also preferred 180mm cranks.

Maybe the best we can say is that some folks want to trade raw watts for other things like feel/comfort/clearance--just like they do with the rest of their bikes.
  • 4 0
 I went to a 165mm crank so I could fit a 170mm dropper. Worked a treat and I now have the bike fit I want. Not really noticed a big change as far as pedalling goes, got 170 cranks in my other bikes, they all feel similar. I doubt anyone will read this comment anyway. Cheers all.
  • 1 0
 I read it, thanks for your input Smile
  • 6 1
 I'm 6'6" and my new XXL Spire came with 165mm cranks. Love them! I honestly didn't even notice the shorter length when it came to pedaling.
  • 3 0
 I’m 6’4” on a new Nukeproof Mega 290 with 175mm cranks…I’ve had more pedal strikes this summer than in my previous 30 years of riding combined. The low bottom bracket is so stable, but causes some serious issues.
  • 2 0
 @unrooted:
Wow, and the 290 is high bb. I’ve not had a single pedal strike on 175mm cranks
  • 1 0
 @rich-2000: maybe I need more volume spacers in my shock????
  • 2 0
 @unrooted:
Or maybe air? at 345mm its not really a low bb for 160 travel bike.

What size rear tire you running? That can make a 5mm difference. And if your air is too low and your shock sits 2-3 mil into its travel, thats another 5mm lower your bb sits.

Worth measuring your bb. Mine is exactly 345mm
  • 1 0
 @rich-2000: I initially was running 30% sag, 2.5 DHF/DHR tires. I bumped it to 25% sag and the pedal strikes went down, and it still rides well…
  • 1 0
 @unrooted: yup, low is slow, high is tight, change out those cranks and breath new life into your sled.
  • 3 0
 "...a longer crank will generate more torque but at a lower rotational speed."

Leverage is important for climbing, which is my main concern. I'm not standing and sprinting, but rather grinding up hills in a 30/48 or 50.

I'd lose a bit of the above leverage to reduce PITA pedal strikes. Take 5mm off of crank length to 165mm, and raise BB by 10mm.
  • 10 5
 It's amusing to think that someone opting for flat pedals over clipless would then argue for a crank length because of power output.
  • 3 2
 well said sir
  • 6 4
 Huh? Maybe you missed the previous article/s disproving the mythical advantages of clipped-in pedaling? There may still be advantages (cadence and staying attached through roughness), but it isn't power output...
  • 4 2
 @audeo03: Yet to see any such 'proof' that isn't really terrible science.
I can ride either but, it's so much harder with flats due to a less efficient foot placement and not being able to pull on the upstroke. Something folk who deny clipless benefits keep falsely claiming you can't do. *rolls eyes*
  • 4 1
 @audeo03: I guess every single WC racer ever also missed your article.
  • 3 0
 @audeo03: It's also the efficiency of being in the same spot every pedal stroke and your flat shoes are as stiff as wet cardboard so most of your energy just goes into bending your shoes.
  • 3 0
 172.5 came on my bike, I put a Cascade link on which dropped the BB 7mm so swapped to 165mm cranks to make up the BB drop and the entire bike feels better. It shortened my RAD to exactly where I needed it, less pedal strikes, I feel more balanced pedals flat descending..mostly it just made the bike feel like it fits me better now. I have been seeing some component companies testing 155mm cranks on ebikes and the riders have been giving great feedback on them so I am very interested in seeing the long term large user group feedback on shorter cranks.
  • 1 0
 Well, just by putting a Cascade link on cannot change the RAD of your bike. The frame is the same and not changing anything such as stem length/height, spacers, bars, angleset, or reach adjust headset will give you the exact same RAD. It will however, change the RAAD, that is, the angle of your RAD. And that's for many just what you need. A relatively longer RAD, made up of a larger portion stack is also what many of new bikes are offering for 2022. (I'd guess this is good for those with normal length arms and even shorter length arms. But is it good also for me with longer sized arms? ‍♂️)

Ebikes just need your input and not really Your full torque, as instead providing this for you. This for me, makes the whole difference for shorter cranks.
  • 3 0
 Swapped out cranks on both my kids bikes for shorter units. My oldest is 5ft 2in and we put a set of 155mm Canfields on his small frame Rocky Mountain. Came stoke with 170mm. Not only does it provide proper crank arm length but allows for the seat post to be not so low. was able to fit a 150mm dropper post in his bike this way too. My youngest is on a 24 in bike and we downsized from the 152mm factory 3x cranks to 145mm HUP cranks when I did the 1x10 AdventX conversion on his bike. I'm 6ft 2 and my newest bike has 170mm. Never noticed an issue going down from 175's. Tempted to try 165mm to reduce pedal strikes. Hardtail Party put out a vid on youtube regarding crank sizing. was an interesting watch.
  • 2 0
 I learned a lot from making that video. Pretty cool to see this article supporting it to some extent.
  • 2 0
 Conversely, I swapped cranks from 155mm to 170mm for one of my kids (10 yrs old & 5’2”). He was instantly faster on the longer cranks when climbing and noted that climbing was easier. All other variables remained the same including gearing.

For myself, I’ve tried shorter cranks a few times over the years and always gravitate back to 180mm. I run 175’s on my mountain bikes now only because I can’t find a good 180mm crank anymore. I’d happily swap back if Shimano made o180mm at the XTR level. For reference, I’m 6’5” and and oddly enough, the height x .092 formula listed above puts me on 180mm cranks.

I really think this is as much of a personal preference as it is related to physiology, trail type, suspension type (mid-stroke support), etc.
  • 3 0
 Maybe crank length is the last domino to fall in the gearing revolution. Back in the 9 speed small-cassette days I definitely needed a 175 mm crank. But with big gears now my 170mm cranks seem just fine. Trouble is that I am not a spinner, I'm a low RPM, high torque kinda guy
  • 3 0
 There are also other factors to consider, as neurotransmitters and central fatigue. A shorter crank means more rpm which means more neural impulses sent to your muscles. Therefore, your neurotransmitters deplete faster and it causes central fatigue, decreased performance, loss of coordination and consequently balance. It also requires more concentration to keep the rpms up, as its very easy to get distracted from your workout with multiple factors. To make the most of higher rpms, you need to train specifically for them. And it's a nuissance. It's another thing to keep you enjoying a nice sweat in the woods, as it requieres you to have a narrow inner focus. But that's me.
  • 3 0
 Not specifically mountain bike related, but my wife and I ride a tandem; a 1993 Miyata DupliCross MTB Steel rigid tandem. I turned it into a touring/bikepacking bike. It is a Large/Medium. I'm the Captain and she's the Stoker. I'm 5' 11" (180cm), she's 5' 6" (168cm). The bike came with 175mm Cranks front and rear. I always thought that was an odd choice given the bike's 2 rider sizes based on the frame geometry.

I ride much more than she does and I would continually over-rev her in cadence and she would complain I was pedaling too fast. Her shorter legs had to extend and contract faster than she liked due to the crank length. All of her own bikes have 170mm cranks. I found a set of 170mm Tandem Stoker cranks that matched the Deore DX cranks the bike came with, and swapped them in. Problem was solved and I could pedal much closer to my own natural cadence since she was now pedaling in smaller circles. I also offset the clocking of the cranks by setting my cranks to lead by 20 degrees, which reduces the load at the beginning of the Power Stroke, but that's another article.
  • 3 0
 Did the title say science shows shorter cranks are better according to science and then list study after study showing little to no difference in power output?

My take: pick a crank length that feels comfortable to you and doesn't leave you with excessive pedal strikes. Adjust gearing, saddle, etc, accordingly.
  • 3 0
 After spending years reading MTB articles (some contradicting), and seeing the zany amount of BB and Axel standards there are here... it's difficult to take this approach seriously. ie: "Just another crank standard?" So instead of starting with the tech/engineering viewpoint of "how", as is often the case, perhaps try an article that highlights that Tour road racers run 160 and BMX sprinters run 185, and why. And then how that applies to MTB and why. Would be educational, and a look past the blinders of our own clique.
  • 1 0
 Good point! These perspectives would clearly help understand why and if one prefers one or the other. Self-awareness is key.
  • 7 2
 What!? The crank I already have are fine? No, I need to upgrade to the newest, best, shiniest thing on the market!
  • 3 1
 At least there's some science to back it up, you can make an informed decision, instead of marketing hype. There's a difference
  • 4 2
 @adespotoskyli: There was zero science mentioned in this article anywhere.
  • 1 2
 @adespotoskyli: You are the victim of a focus group. LoL
  • 1 1
 @alexisfire: I guess you skip past where it says study x and there's a link to the study. But hey, if that suits you, it's fine
  • 1 1
 @m1dg3t: or the studies actually provide some data to support their findings, maybe
  • 2 1
 @adespotoskyli: Studies? LoL. Easy on the confirmation bias there buddy. Only 1 paper was recent (2021). The next most recent was 2016. No papers with rebuttals. This would get laughed out of a community College if you tried to hand it in.

Like I said; You are a victim of a focus group. Remain blissful in your ignorance.
  • 1 0
 @m1dg3t: every study above is peer reviewed and published, go on and prove them wrong. I'll wait. Also how come publication date has anything to do with the results and findings of the study? Cyclists evolved from 2001 to the point the studies are irrelevant? If you think they did it wrong take the responsibility and publish your own work and findings, enlighten us. Or make your own rubuttal papers, for the time being I'll take the studies instead your opinion.
  • 3 1
 @makripper
Exactly - once a rider's average riding speed gets into the double digits, wind resistance becomes a factor. Especially in the world of curly bars and XC, shorter cranks = higher seat position = more wind resistance. Expand that drag over a 3 hour race on a fast course, the gram counters looking for incremental gains will likely opt for less wind resistance, thus 170/175 crank options.
  • 3 0
 The top guys use 100% custom cranks
  • 5 0
 Interestingly, a lot of road and time trial riders opt for shorter cranks specifically to reduce frontal cross sectional area and wind drag. Shorter cranks reduce hip angle when pedaling by lowering the top leg during the pedal stroke, and a smaller hip angle allows riders to comfortably bend over more and get their head and torso out of the wind. So it’s 5-10mm higher for the bum but 10-40mm lower for the head and torso. Trade offs.
  • 1 0
 @TEAM-ROBOT: do you see any benefits of a shorter crank in the non competitive side of mountain biking? Thats what I'm trying to sort out. I like a longer crank for a better stance for downhill
  • 4 0
 @makripper: I've run 165's, 170's, and 175's, and I've settled on longer cranks with 170 on the downhill bike and 175 on everything else. Granted, I'm tall with long legs, but I love being able to apply high torque at low RPM in technical moments, and I love having back pressure on the pedals at all times instead of spinning. If you scroll up, there's a little conversation going on in the comments about the benefits of longer cranks for technical pedaling, and I gave a longer answer up there.

BUT! Those long crank benefits are all relative. If you're a shorter rider, if your bike came with a stupid low BB, if you naturally pedal at higher rpm, or if you're only ever pedaling on smooth singletrack and firereoads, then shorter cranks might be the bees knees for you. Somebody else in the comments even mentioned being able to find the pedals easier with short cranks when you're doing no foot cans and tailwhips. Tailwhips aren't my cup of tea, but obviously short cranks can be helpful for a wide variety of use cases.
  • 5 0
 Are manufacturers actually making shorter crank arms, or are they simply adjusting where the pedal threads in?
  • 7 0
 Both. It depends on the brand and crankset
  • 2 0
 @VtVolk: Which brands are making legitimate 170 and 165m crank arms?
  • 3 0
 @TerrapinBen: Shimano in my experience with XT/XTR and on the road side, Ultegra and 105
  • 1 0
 oh snap
  • 10 2
 Our crank arms are properly sized so you have maximum clearance for any given length.
  • 7 5
 This is a really good engineering/science article from Pinkbike. Not one person's limited/biased/potentially incorrect analysis, but a review of published journal studies.

That said, I need to go and see what size my cranks are! Not that I can find a new set in stock...
  • 1 0
 I don't agree. The article sets the scene and certain comments are what make up all the relevant content for me.
  • 2 0
 "A commonly made argument is that longer cranks *lower gears* offer more leverage, meaning more torque can be generated for a given force at the pedal. This is true, but leverage comes at a cost. If you can move your pedal with a certain force and at a certain speed around the circumference of the pedaling circle, a longer crank *lower gear* will generate more torque but at a lower rotational speed (rpm), because the circumference *of the larger cog* is bigger. Power is just force times speed or torque times rotational speed, so either way, the power is the same (at least in theory)."

Single speeds for all!!

On an unrelated note, how does one format comment text? ;-)
  • 2 0
 Given that a certain person has a maximal force output for a given crank length, it would stand to reason that they would want smaller gear ratios to utilize their ideal/comfortable/maximal...whatever power if they go to a shorter crank. The wheels of commerce continue turning Wink .
  • 6 0
 That was a lot of reading to basically say... do what you want.
  • 1 0
 ...but other comments than yours make up for it. ;-)
  • 3 1
 Happily running 175s at 5’7. I tried 170 and didn’t like it for the riding I do. I find it easier to accelerate out of tight corners with the longer cranks, and I need less torque for wheelie drops and stuff. The wider stance is also nice for stability.
  • 3 0
 Sssh, pipe down at the back there, we're all meant to like 170mm or shorter cranks these days!
  • 2 0
 @pipm1: Haha :-)
  • 2 0
 5’10 1/2”, ridden 175 for 20 + years. The gravel bike has 172.5’s and the dh bike has 165mm. I am not a fan of the 165mm they feel too narrow and cramped when used horizontally as a platform( mainly descending ).

Science can talk all it wants about how the crank lengths affect the pedals in motion, but it’s missing the other 50% of the time that you’re riding without the pedals moving….
  • 6 1
 Kind of misleading title as the article says only 3 out of 7 says better and the other 4 days no difference
  • 2 0
 Gotta love these pseudoscience reports with ridiculously small sample size. Let me be a dick about the lack of 180mm cranks and how my 37-inch inseam-length legs prefer the torque I can transmit in a climb. The 165mm cranks I've tried suck. I can spin, but I can't low-speed crank up a hill and you can't spin as easy out of a saddle in these climbs.
  • 2 0
 The Ride Far website did an interesting article on this a while back and the TL-DR takeaway was much the same but with endurance riding there was a big benefit re comfort with shorter cranks. Endurance riding by its very nature shows up any problems with poor bike fit very quickly.
ridefar.info/2017/02/crank-length-and-comfort-for-long-distance-cyclists
  • 2 0
 I’ve always found it odd that riders try to buy the thinnest pedals (within reason) they can at the expense of bearing life and durability to increase ground clearance, but never even entertain the thought of running 165mm cranks instead of their 175mm ones.

Also it annoys me when companies make a shorter crank that’s actually the same length but with the whole drilled in a different place.
  • 3 0
 What about posture and cornering?

Would shorter cranks affect your stance negatively when you're pumping and pressing the bike?
Are longer cranks better for getting your CG lower?
  • 2 0
 More accurately/thoroughly, as crank length increases, its leverage on the drivetrain increases, but at the same time the leg's leverage on the crank decreases (assuming equal leg lengths) ; and vice versa. Proabably just about cancels out except for the extremes, and within the limits of biomechanics.
  • 2 0
 What about the efficiency of balance and mementum generation from pumping? Seems that feet and legs closer to together may provide a benefit. Ever try to jump from a lung position? Much easier to jump higher when your legs/feet are closer together.

This old man, hit the dirt jumps at highlands and rear knee was buggin and I switched stance for the rest of the session: was able to contemplate why me rear knee might hurt more mechanically and decided smaller crank arms might help more evenly distribute the weight.

They should test pump track racing with smaller cranks and observe the outcome. Also test closer gaps in crank length to optimize/tighten those graphed curves. 170, 165, 160, 155

These guys in the test are trained professionals riding the same cranks everyday for multiple years. Let’s see what the average Joe finds out.
  • 2 0
 i will run shorter cranks when droppers get longer, 210 isnt enough for me now so why would i want to raise it more?
And i've tried 165-170-175, 165 is too short and my seat is so high i cant get it out of the way at all, it also made me feel like the bike was too small for me, feet were noticeably closer together and it felt odd, like any movement over upper body was extremed out. 170 was better... but then 175 is golden, strong platform to stand on and just charge hard it also let me get my seat 10mm down more which may sound small but thats the differnce between my Balls touching the seat or not.
Ground clearance is a mute point as id rather the big platform an is more effected by BB height than crank length

A friend of mine reckons its to do with motorbikes, as ive noticed alot who ride them or come from them will prefer shorter cranks.
  • 2 0
 On my opinion, shorter cranks:
- Slightly lower the weight.
- Should be slightly stiffer than the same crank with longer arms.
- Slightly increase grip on slippery climbs: faster cadence should result into a more constant power output as there are shorter "dead" gaps in your pedal stroke).
- Allows you to dive into a more aero position: when your cranks are in a vertical position while pedaling, your upper knee comes up less high, so you can ride with your handlebars lower with the same flexibility between your upper leg and torso (mostly interesting for roadies).
- Have less chance on rock strikes or hanging up.

Because of this, I run 170mm cranks on all my bikes.
  • 2 0
 I know these are mostly nearly neglectible gains, but when it costs the same, why not just choose the shorter cranks?
  • 2 0
 For riders over 6'3", the 2d to last sentence about seat post height is huge. Until companies start making bikes bigger not just longer, a lot of saddle heights are already telescoped and raising another 10mm will slacken effective seat post angle reducing climbing efficiency, put the seat in the way on the way down, and generally look goofy!
  • 3 0
 Another argument for steep seat tube angles. That effectively isolates the seat height from the seated reach (can't remember the right name for this measurement, top tube?) so no matter how tall you are/what crank length you run etc you still have a bike that pedals well.
  • 2 0
 What about for stability while descending? Wouldn't cranks that are spread further apart have more stability with a wider rider stance? If we are talking 175mm vs 170mm, our feet would be spaced 1 cm wider or shorter... I haven't tried different crank lengths so never considered this until now...
  • 2 0
 Without reading all of the previous 442 comments, I have some thoughts to add to this discussion.

1) With a shorter crank, I’d rather also lower the BB rather than raise the saddle height and increase my CG when pedaling.

2) Most frames are now designed to best suspension performance with a specific chainring size, Things like chain / chainstay clearance may need to be adjusted too,

3) This means that a frame will need to be redesigned to take best advantage of shorter cranks.

4) Sounds like a great marketing opportunity
  • 1 0
 I have read all the earlier comments and yours was the first to mention suspension behaviour. Thank you. I’m not going to change my crank length and go down in chainring size if it’s going to change the suspension on my bike.
  • 1 0
 @Afterschoolsports: Yep! Smaller chainrings increase anti-squat to some degree, although I doubt most people would notice a big difference going from a 32t to 30t ring. As I understand it, increased anti-squat can improve pedaling response at the expense of pedal kick-back. (Especially when pedaling through rocky / rough tracks) I’d love to get an engineer to weigh in on this. (Also, some suspension designs are more affected than others)

Primarily, my comment was meant to address the fact that any change on a modern bike can affect the whole system- so rushing out to make a big change on your current bike can have unexpected trade-offs.
  • 2 0
 @basic-ti-hardtail: there are some bikes I’ve owned in recent years that I definitely would not want more anti squat. A giant trance was one of them. It rode great uphill but when I actually needed suspension the pedal kickback was horrific.
  • 3 0
 I own 2 sets of Canfield 150mm cranks, love them. My other bikes (Evil Chamois Hagar and old Hardrock) have 165mm cranks. I am 6’1” with a 32 inch inseam and bad hips. The shorter cranks have been lifesavers.
  • 2 0
 I'm 6'4" and running 165mm on my full suspension and love them. Better clearance, smoother pedal stroke and no downsides I can tell. I am running 170mm on my hardtail since I have a smaller gear range (11spd vs. 12spd on the full suspension) and I tend to stand and mash more on that bike vs. sit and spin on the squishy bike.

Great video comparing different crank lengths back to back: canfieldbikes.com/blogs/news/does-crank-length-matter-hardtail-party
  • 2 0
 Here we go again. As usual, a light weight article to raise "discussion".

Until the "conclusion" it downplays the torque needed in highly tech rocky/steep climb situations, nor the inability to "spin" and develop that needed power when bouncing around in the same. Comparing apples to apples, there is a loss in power and you need to use lower gearing to compensate so you can "spin"? Ha! Try that when you are bouncing on a steep climb and lose traction.
  • 2 0
 Funny how six of the seven studies tested only men with their narrower Q angle. I'm 5'4" with short legs, and have always disliked the 170mm cranks that came with my vintage RockHopper. My knees aren't too terribly fond of them either. Sheldon Brown, in one of his rare failures, compares cranks to stairs and short people climb the same stairs as tall people, so crank length doesn't matter. Except we don't climb stairs for 30 miles.

But the industry builds for taller male riders j(google "reference man"), and women just have to adapt. E.g. Once I discovered the joys of 26" wheeled bikes that actually *fit* me, I refuse to go back to 700c.

I was lucky enough to find a Sugino 160mm crankset; they make them in all the lengths, but I could only find the shorter lengths on Sugino's website. I can't wait to put it on my bike.
  • 1 0
 Agree. For decades I never paid any attention to Q-factor until my wife developed severe knee issues requiring surgery from riding with a setup that exceeded her alignment limits. Now, as long as we keep her to a Q of 158mm or less, she's golden. On one bike I was able to shift her shoes inward enough to compensate for a setup that had a Q of 163mm, she does rub the cranks occasionally. Unfortunately her Q limit eliminates many more modern bike options like boost rears or virtually all e-bikes.
  • 4 0
 LOL, 165 was about the only crank length you could find in stock. No wait... OUT OF STOCK...
  • 2 1
 What about stability??? If you want to ride downhill, jumps or drops? I like my feet a decent distance apart for stability. I have had a go on a few bikes and I don't like it when my feet are too close together. We're not all just riders who want pedalling performance, we're freeriders!
  • 3 1
 What does it matter how far apart your feet are? The cranks still rotate around the same point
  • 2 1
 @Tambo: Cranks aren't rotating at this point...
  • 2 1
 @alexisfire: As soon as you put more weight on one foot than the other, which is the only way you could gain stability from the wider stance, the cranks will rotate. Yes your feet are further apart, no it isn't more stable.
  • 3 2
 Not much practical information above.

You generate movement through how hard you push the pedals and how fast you spin the cranks.
Depending on what your are trying to do, climb a steep hill, go fast on the flats, you can adjust either or both. So what are the pros and cons of shorter cranks?

The length of the crank affects the torque output of your pedal stroke. (Shorter lever). For the same gear and same power pushing on the pedals, shorter cranks means less torque. This means harder to move the wheel around once. A rider with a lower torque will have to push harder and/or pedal faster, or change up to an easier gear, to keep with someone with more torque on the pedals. So shorter cranks might be less effective, unless you have strong legs. Or you can just shift up to an easier gear and bingo, more torque. So leg strength is less of a factor now in the easier gear. Is there a practical limitation for most riders? No. Most people don’t have strong enough legs to turn the cranks in big hard gears anyway so we use our huge easy gears.

Since shorter cranks travel less distance around the crank in a circle, most people can spin faster with shorter cranks. (Higher cadence). Force = Power (pushing the pedals) x RPM (crank speed = cadence) and it’s generally easier to get more force by increasing cadence, especially on a mountain bike where there is lots of cadence to gain. (Most people spin slowly sub 75rpm). So, even though the reduced torque might be a con in some scenarios (slow, grinding, standing climbs up Slickrock). It can be easily offset using that 50t platter and a slightly faster cadence.

And you get more ground clearance.

There are some mtb scenarios where high torque gives you an advantage, but with modern low gearing at 45t to 50t coupled with a 26t to 30t chainring, higher torque is easy to get by changing gears.

Leg speed ultimately determines output. It always has.

(Mostly stolen from below)
Reference:
www.flammerouge.je/factsheets/torque.htm
  • 4 0
 165 on the Enduro and 170 on the XC bike. Pedal clearance vs saddle height is what it comes down to for me.
  • 4 0
 Power is how fast your pedal strikes the rock. Torque is how long you can perform a Dead Sailor after striking said rock.
  • 1 0
 I'm 5'7" (170cm) in height, and have been using 135mm cranks for over a year now. It feels like I've lost my granny ring equivalent, so I've been running small 28t/30t chainring to help compensate. It did take a couple of rides to get used to the initial different pedaling feeling, but the body quickly adapts to the new normal. All in all, it's fine, and I won't be going back to standard length cranks anytime soon.
  • 1 0
 I'm tall-ish at 6'3" (190cm) and long-legged. On my road bikes I've experimented with 177.5 and 180 cranks.

On my mountain bikes I've moved to 165.

I don't do long endurance pedaling sessions at a fixed cadence on my mountain bike. There is tons of cranking uphill and coasting downhill. But with shorter cranks I get far fewer pedal strikes, and that more then accounts for anything negative that might come out of a shorter crank.
  • 2 0
 Which cranks do you have? This is usually just mental. Most cranks just move the drill hole up the crank and use the same length crank.
  • 2 0
 I have some 150mm Canfields. Maybe for some short legged XC or gravel grinder would they be beneficial. But for technical ups where bursts of speed are needed. They were horrible. Back 165 I went. I have a 32in inseam.
  • 3 0
 not so much for the science benefits, but just to eliminate the huge cassette and achieve low gears, I run 160 cranks on my 27/26 mullet
  • 3 0
 Trials: 175 for stock, 165 for mod. Almost none of this applies when you're not doing full pedal strokes and only "punching" the pedals.

Good read though...
  • 1 0
 So, what's stock and mod?

In the past I've mostly punched my way through chunky lines in the woods. I don't really know how my riding has evolved though...
  • 2 0
 I'm no scientist, but having ridden 150mm cranks, I'll stick with my 170s lol. don't super understand the whole rpm/cadence over leverage thing, I only noticed the massive decrease in leverage.
  • 1 0
 why ten manufacurers install 175mm cranks so commonly and they are much cheaper than 165 beside that they use more material?

"you will buy bike with shitty long cranks and pay for them, than you will pay again for shorter better cranks. profit"
  • 1 0
 Shorter cranks are better in every way BUT saddle height - I don't like the sketchy feeling of being super high up on the bike on technical climbs (or generally), and as the article correctly stated shorter cranks = higher saddle. For that reason 170 is a happy compromise for me.
  • 1 0
 But you and the article fail to remember shorter cranks allows you to run a lower bb by the same amount you just had to raise the saddle. Right?

But of course there's a point where you want to Not lower your bb by the same amount as you shorten your crank, to be able to clear rocks by keeping your pedals level over them (and not bashing your chainring or bash guard). At that point, you want to minimise the size of your front chainring. I just hope the new gearbox from Shimano solves all this for us, haha
  • 2 0
 @DuRietz: Exactly - everything is a compromise and needs to be in balance. I ride a v4 5010 in the higher bb setting for riding jank and natural/super rocky trails. I also like a poppy playful ride and lowering the bb makes the front end of the bike feel heavier (hence why street BMX bikes have high bbs). I also like to smash bigger gears so could never go smaller than a 32t chainring. So everything considered - shorter than 170 cranks on a bike I pedal a lot sat down doesn't work for me.
  • 3 2
 2 sources from the last 5 years. 5 sources that are 10yrs old or older... ROTFLMFAO An academic paper this is not. Seems more like confirmation bias to me, but hey they gotta sell more cranks some how! C'mon people. Everyone needs to go out and buy 165mm cranks to replace their 175mm's LoL Push those sales Seb! Buy. Buy. Buy. Buy. Buy. Buy. Buy. Consume. Consume. Consume. Consume. Consume. Consume.
  • 1 0
 Spot on.
  • 1 0
 For all the dirt and slopestyle buddies!! 165 all day. Changed from 175 (ridden all my life) to 165 last year. Absolute game changer. My numbers 6 feet, 207 lbs. Stiffer crank, easier manuals, easier tabletops or its variations, easier to catch tailwhips etc. overall different/more stable feeling. It might be wrong but it feels more efficient but I´m just riding standing.
  • 1 0
 Good luck with finding cranks shorter than 170mm. I took me a few days to find cranks for a bike for my daughter. The shortest from SRAM is 165mm but at the moment only for SX and NX. The only one shorter than that that wasn't a square or micro spline bottom bracket was from Suntour. For kids longer cranks cause the knee to come up really high, a 170mm was too long for her, she's 10.
  • 1 0
 Does a kid's bike really need something other than square taper? It works just fine and lasts a lot longer than outboard bearing in my experience, Even for adult bikes.
  • 2 0
 @Zhehan: It's heavy, there is no info about chain line and most of all it is not "cool". Square taper on an adult MTB is asking for disaster.
  • 1 0
 @chrsei: I was just thinking kids bikes and non-MTB bikes for square taper being an ok thing. Generally, MTB Square taper spindle length is 113mm for normal chainlines and 8-9 speed drivetrains. However, I ran square taper Shimano FC-MT510 HollowTech cranks for years on my 2004 Trek Fuel 95 XC bike with no ill-effects. I wasn't doing downhill or huge jumps mind you...

Anyway, for that old stuff, the recommended spindle length usually accompanied the rest of the spec info about the cranks...
  • 1 0
 To fellow XC weightweenies.
Lightest "official" 165mm 1x MTB crank without power meter is Sram X01 Dub. Yes, it's X01 because Sram don't do XX1 3 bolts in 165mm length anymore. Go find it and you'll only see 8 bolts option (for use with Quarq spider) if you specify 165mm length. Sram somehow think XC riders that can afford XX1 but don't use power meter only use 170 or 175. But if they are serious enough that they care about power then 165 is on offer...
X01 will end up around 480g-ish. Still lighter than Shimano XTR which is around 510g-ish.

However, by going 3rd party chain ring, you can certainly drop more weight by using XX1 Dub which is 8 bolt spider interface together with 8 bolt direct-mount chain ring. I don't see many options but ALUGEAR make some. This will end up around 430g. It's a few grams heavier than XX1 with 3 bolts because there are 5 extra bolts securing the chainring. That's it.
  • 1 0
 I'm a little over 5'10", have experimented with this a bit myself and eventually settled on 152/155mm cranks.

Dropping that far didn't have a huge difference in feel and seemed to be all benefit -- a significant reduction in pedals strikes and a lot more flexibility for what I could just pedal through vs. needing to be more careful about pedal positioning.

Went down to 140mm for a season and while they felt OK for seated pedaling, standing pedaling felt slightly "off".

This winter's experiment is riding with longer cranks arms on a stationary bike for indoor training. The idea being that adapting to a faster cadence on longer cranks will translate to it feeling even easier maintain the same cadence outside on shorter cranks.
  • 1 0
 Had about a dozen pedal strikes in the past two technical rides with my 175mm cranks at Skyline in Napa and Camp Tamarancho in Marin. Super annoying. Was ratcheting like crazy but still kept whacking the pedals.

This article is speaking to me!

Now I just have to figure out how to switch out the SRAM S-2200 Carbon crankset on my 2016 Stumpjumper FSR to 165's (or 170's?) that are good but not too expensive that fit. The more I read about bottom brackets and cranksets the more I am confused.
  • 1 0
 Maybe you just need to service your rear shock to get the bb up again. That was the case for me! A ridiculously low bb will not be good for you even if you get shorter cranks. It is such an easy sell by articles as this - if you don't read the comments where you will find a lot of accumulated knowledge by us fellow users. Good luck!
  • 1 0
 165 is where it's at. I would never have thought so myself until I read a similar article on this subject just a couple of years ago. I've always ridden 175-180 cranks. Over 40 years of riding. My new Vitus Is so slack and long and the BB so low that I had to do something about it. I increased my rake and raises the BB some but when I went with 165 cranks it did what I needed it to do and surprisingly it was very comfortable. I'm 6'2" I never thought I it would be as comfortable as it is but it really is. But it do love me a high BB and some long 190-200 cranks for some big air. The way they make bikes now it's just not something that you can find...and I've looked. The intense recluse is probably the highest BB out there last time I checked and it's not all that high really. Happy trails y'all
  • 1 0
 he thing that I have always wondered in the long vs short crank debate is not about power output, but about balance. So when standing on level crank arms, the longer the crank the farther your feet are apart creating a wider (and more stable) base of support, which sounds like something positive to have while bouncing down a hill.
  • 1 0
 For cog, whether or not you raise your bottom or seat post seems to be of little consequence, and since rings and cassettes are designed around 170 to 175 mm arms and that’s where the best range of gearing is to be found, why even bother designing anything around 160mm arms? Unless of course, we need another design standard to sell shit.
  • 4 1
 170mm gets you across the lake much faster than using 150mm for stand up pedaling.
  • 4 0
 Dang! My wallet can't handle another crankset.
  • 1 0
 No worries. This is just marketing. Though, you may think about servicing your rear shock, if it's due for that.
  • 6 2
 Hear that??? The winds of change.
New short-crank-specific geometries...
  • 1 0
 its wack trying to find pedals on 175 cranks when u take your feet off in the air. Clipping the ground and shit all the time too. Wish it was easier to find shorter ones right now.
  • 4 0
 Don't be silly baby... I love your short cranks.
  • 3 0
 For road bikers, xc and gravel racers it matters. For everyone else. Nope. For dh a like a longer crank.
  • 6 1
 165 or die!
  • 5 1
 165mm is best crank flavor.
  • 1 0
 Shimano cranks have been back ordered for months along with every other bike part. Ordered two sets of 165s for my bikes in August and they’re not expected to be in until Feb
  • 1 0
 I know this doesn't help, but SLX 165mm cranks have been coming into stock now and then in the EU and UK. I just had to keep checking various retailers.
  • 3 2
 I've been running 165mm Canfield cranks since 2015. Kinda surprised and disappointed that there's no mention of Canfield Cranks, since they were the first to offer short cranks.
  • 1 1
 As a single speed mountain biker with 170mm cranks, who stands all the time, even on all day rides, I think everyone should just pedal harder!

The real question is why can’t we have more color choices in our cranks and other parts?! This is supposed to be fun!
  • 3 0
 More torque! More torque! 180's on the DJ, 180's on the XC, stupid 175's came on the enduro, weak...
  • 2 0
 It’s so cute how mountain bikers try to compensate for their small testicles by overcomplicating trivial things such as crank length, suspension, and weight.
  • 4 0
 My bike is unrideable now
  • 4 0
 Why is everyone so cranky?
  • 3 0
 Just in case someone needs to hear this today: this article doesn't make your existing cranks worse.
  • 3 0
 I have a leg 15mm shorter than the other so my cranks have different lengths. It stopped the knee pain.
  • 1 0
 I'd have lowered the seat by 15mm and spent the money in beers like everybody does (we all have one leg shorter than the other).
  • 1 0
 @Zeeroone: 15mm is three times the average discrepancy. Compensating with a mismatched crank sounds like a great idea to me.
  • 2 0
 Interesting... Now, what about handlebar widths? Is there a significant increase in leverage between a 700mm wide bar & an 800mm wide bar? *Thinking Emoji*
  • 2 0
 Yes, of course, though there are other factors worth considering such as shoulder width and whether you ride in the middle of trees.
  • 3 0
 These studies are all questionable since they did not utilize dropper posts or baggy shorts or steep seat tube angles.
  • 1 0
 The problem is you can't even find 165 cranks that are 73mm BB almost all of them are for 83mm DH bikes. I've been looking for a pair of carbon 165 for my SJ Evo and its like they don't exist
  • 1 0
 Don't mind then. Keep your suspension serviced and well set up and you're fine.
  • 2 0
 5'5" (165cm) running 170mm cranks. Tried 160mm cranks on the new Levo and it feel so natural and great. Just wish there were more options to go 160mm or shorter.
  • 2 0
 It would be fun to have Pinkbike run a test on a few of their riders double-blind testing different crank lengths on a steep tech climb and a long fire road climb for time.
  • 2 0
 It is impossible to test something like this with any kind of double blind or even single blind study because the rider and the testers can both see and feel the differences in crank length. It would still be interesting to compare them back to back like they do with the bikes on the field test. The only issue is that I imagine there is some element of training your body to match the crank length and the cadence they promote so you would end up with the results favouring what the riders are used to.
  • 1 0
 @Patrick9-32: I expect that you can't see a difference between 165 vs 175 mm cranks without comparing them side by side. If that is so, then having a mechanic change out the cranks who is different than the tester would provide the double blind. If the riders can experience a difference in the cranks without preconceived expectations would be a useful outcome of the test.
  • 2 0
 Even if you do hire people so short sighted or unfamiliar with looking at things that they can't spot 10mm of difference between two cranks it doesn't change the fact the rider can easily feel the difference, especially if they are an experienced rider, which they would need to be for the data to be useful.
  • 1 0
 @Patrick9-32: You can look at a crank arm and tell without measuring it or comparing it side by side, whether it is 165, 170, or 175 mm? Doubtful. It would be a primary purpose of the test to see if the riders can feel a difference between the cranks with no preconceived knowledge of what they are riding. This would be useful information.
Many of the ride reviews and comparisons are compromised, in my opinion, because the rider is expecting a particular result, and the ride feel of a bike is so subjective that it is easy to be prejudiced.
  • 1 1
 1. Of course shorter cranks are preferred. When bike companies keep designing bottom brackets lower and lower to the point they basically drag in the dirt.
2. Pedaling at a higher rpm is preferred because mountain bikers are progressively getting weaker. Example: Eagle cassettes.
  • 1 0
 Eagle cassettes still offer less range than a 20 or 30 years old triple ring drivetrain, whose lightest gear was already sufficiently low for anyone.
  • 1 0
 @mrkumro I get your point. But @DavidGuerra is right, even though range dropped there in the beginning of the one-by.
  • 1 0
 Also, extra range doesn't necessarily mean lighter gears. Just depends on chainring size. Plenty of people buy larger cassettes so they can use a larger chainring and get heavier gears. Either way, the lighter gears on a bike were typically tailored to what an average rider or begginner might need to handle a steep climb, it was only the smaller range cassettes (around 420%) that changed this for a while, and the manufacturer's chainring size choice either put weaker riders in trouble on the steepest hills or left stronger riders with a great lack of heavy gears (or, most often, a mix of both cases).
  • 1 0
 Well, several years ago I told Joan Jones I wanted use 180mm cranks in a race, and she said I'd be laughed off the circuit...so if you want to know something ask someone who knows what they're talking about!
  • 2 0
 Short cranks are NOT good out of the gate….besides you all never put DESIRE into the equation….think about that once in awhile will ya!
  • 1 0
 I got a set of gx 165mm cranks as I was in a hurry to build a bike and that was all that was available.After 2 or 3 rides I couldn't notice the difference from my previous 170mm cranks to be honest
  • 1 1
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  • 1 0
 i use to run 150mm cranks on my DH bike, the bike felt amazing from a handling side cornering felt amazing but of the line or on flat starts i was so slow had no power it was sapped out of my by the suspension
  • 2 2
 Good luck finding 165mm cranks. Anything besides 170 & 175 are non existent. I’ve been trying to go shorter ever since the BBs got lower.

@blinglespeed I told you 165 was better
  • 4 1
 We make AM/DH rated cranks all the way down to 150mm.
  • 1 0
 @canfieldbikes: thanks homie. I see 165mm is out of stock. Should I dive into 160 for trail use?
  • 2 0
 So with 44.5 Inch long legs - that calculated to the optimal crank length of 230mm. Yeaaaah, no.
  • 2 0
 I find my 165mm cranks are better for sit n spin and sprints, and the 175 is better for techy climbs and low speed twists.
  • 4 0
 fuck yeah, science
  • 3 0
 Girls only want me for my short cranks... ☹️
  • 1 0
 I've been riding 170mm since 85 and have had to replace every crankset on all my medium mountain/road and cross bikes every time which sucks! please industry make the change!
  • 4 1
 I disagree with the title of this article so I'm not reading it.
  • 2 0
 and now we all cut down one centimeter of length... because the science says so!...Big Grin
  • 3 2
 BULLSHIT!! I would argue the shorter/less powerful the leg the longer the crank needed. Which is why with my short unpowerful legs I’m 175 for life!!!
  • 3 0
 Subjective science is always right
  • 2 1
 175 may be good for you for whatever reason, but leverage is not a factor in choosing crank length. The selected gear is what ultimately defines leverage, regardless of whatever leverage the crank arm provides.
  • 2 0
 Lets just get rid of cranks and just use a motor. Max power and no foot strikes
  • 2 0
 Wasn't this reported on by Singletracks like back in March? How did it take so long for this to show up here?
  • 1 0
 Too busy celebrating the sale to outside.
  • 4 3
 Science... There is always a paper somewhere to support an argument. Even some science dude will have a paper to show the world is flat. Lol.
  • 2 1
 Few years back I switched to 180mm cranks. Wouldn’t go back. Never. 175 or even 172.5 now feel just wrong and toy-like. Oh, did I mention that I’m 198cm tall?
  • 2 0
 There's no mention here to the fact that some people prefer a lower or higher cadence, and there's a better crank length for each. However, for the given rider height/crank length ratio, 180mm is still considered short for you.
  • 2 0
 now everybody will buy new shorter cranks! thought it was a climate crisis.
  • 3 0
 Ok, now what about Q-factor?
  • 1 0
 Don’t want to cause panic but Hope make a 150mm crankset which will obviously make you win bigly.

Sound of internet breaking…
  • 2 0
 I run 165’s for my hobbit legs but what I really want to know is, do I need to be wearing pit vipers to achieve the gains?
  • 3 0
 Good meta-analysis. Thanks!
  • 2 0
 Now I need a new bike because my cranks are too long and the bike industry told me so...
  • 3 0
 Buy/Sell: *inundation of 175mm cranks*
  • 1 0
 none of these studies appear to examine rates of repetitive stress injury between long- and short-crank enthusiasts, now that would be interesting
  • 1 0
 165mm works well for my riding, especially after increasing air spring length in my fork, and installing an angle head set to slacken head tube angle.
  • 1 0
 Well, it's all about balance. But you didn't say if the net result of uping travel in your fork and installing the angleset was a higher or a lower front end...
  • 1 0
 the better question: why do people think 10mm makes a difference in rock strikes for crank arm length....but then use massive thick pedals
  • 2 0
 Boost cranks are the next shit.
  • 3 0
 you do know shimano has cranks for non-Boost, Boost and Super Boost, right?
XT8000 vs. XT8000 B-1. Now it's 8100/8120/8130.
  • 1 0
 @ReformedRoadie: IIRC shimano states the 8100 is for non-boost (142) & boost (14Cool frames, 8120 for boost frames with wide (plus) tires and 8130 for superboost. I bought a 7120 165mm crank this year for a boost frame to get the wider Q factor and haven't looked back since.
  • 1 0
 per calculation I should be on 169.2 currently on 170 so no complain there, used to have 165 did not notice any difference
  • 2 0
 I wish they'd tested with 165mm since thats a widely available size.
  • 2 0
 Come for the comments....
So is 170mm dead?
  • 2 0
 Hanging by a thread. 175mm is dead.
  • 3 0
 yes 165 all the way
  • 1 0
 @mi-bike: ohhh MY GOD!
I knew I shouldn't ride my mtb with old, dead and old school 175 cranks! No stravakoms...no smiles....no likes....
Will swap asap! Don't want to lose all my trailfriends
  • 1 1
 Whatever Q factor is also wrong. Your feet do not need to be as close to the bb as possible. As for crank length. It's a personal choice depends on how , what you ride.
  • 2 0
 Zinn thinks Pinkbike and science is fake news.
  • 1 0
 Specialized has made the change to smaller cranks on the turbo levo. 165 across the board.
  • 1 0
 I put 150mm cranks on my wife’s Shuttle, she loves them!
  • 1 0
 @jasonlucas knows a thing or two about short cranks. It's bad for your ankles, though.
  • 3 0
 fake news
  • 1 0
 I'd like to know how crank length affects the torque and midline stability of a rider as their feet move further apart.
  • 5 4
 Is this the same science that said it's only going to be 2 weeks to stop the spread of covid just asking for a friend
  • 4 0
 Fun fact: Science is just one guy.
  • 1 0
 longest two weeks ever
  • 1 1
 I’ve tried 165, 170, and 175 cranks. I didn’t notice much of a difference in pedaling style, but I did notice a surprising difference in rock strikes. I’m 6’2”.
  • 1 0
 Why do I feel like this is a way to re-sell all the old, snapped carbon cranks…
  • 1 0
 I must b a phuqing bike wizard
Been on mullet setup with 165 cranks since 2015 ???
  • 2 0
 Shoot up with boosters and be a dick about it
  • 1 1
 I switched to 165, then 155 cranks after hip replacement. That was three years ago. I’ve seen no downsides, and a lot of upsides. Now a bike with 175s just feels wrong.
  • 1 0
 just read the headline and thought this comes from dan roberts Big Grin
also so gladly read.
  • 2 0
 Short cranks solved my knees pain. 165mm works!
  • 2 0
 yep, it was a great benefit that was apparent after my my first two rides over 30km
  • 2 4
 All I can see in the comments is 90% negaitivity, this is an excellent article that's saved pinkbike readers an awful lot of homework and possibly their knees whilst offering a no-brainer performance advantage. Thanks for the effort Seb
  • 1 0
 I've been running 175 cranks for decades i finally switched to 165 and it has changes my riding style for the better.
  • 2 0
 Flip chip cranks incoming.
  • 1 1
 I'm on a bike with a super low bb (Fuji Auric LT), long cranks made corners and technical climbs kinda annoying, went down a cm in crank length and haven't looked back since.
  • 1 0
 Go get those 180mm cranks if you don't use a dropper post, for better control in the descents due to the lowered seat.
  • 1 0
 “Hung like a field mouse.” Best description of the perfect length I’ve heard!
  • 1 0
 Raising the saddle means also raising the bars to maintain the same pedaling geo unfortunately.
  • 1 0
 DH, DJ, BMX, ROAD, FIXED all 165 for life.
  • 1 1
 This is the kind of hard hitting analysis that Kees me coming back to PB. Excellent article Seb!
  • 1 1
 Also, ever since Q told me to storm the capital and take horse meds I stopped listening to his advice on pedal ergonomics
  • 1 0
 problem is nobody produces anything below 165mm
  • 1 0
 Cool , now I can justify hope children crank's , thanks @seb stott
  • 1 0
 So size doesn't matter, it's how fast you move it that counts
  • 1 1
 Shorter cranks improve how you stroke your pedals. You go faster harder and longer....
  • 1 0
 Should have interviewed Remy Morton for this.
  • 1 0
 According to science huh..it must be true then.. hahaha
  • 1 0
 Good luck finding any short cranks to buy right now.
  • 1 0
 165 sweet wings ebike cranks are out!
  • 1 0
 I switched to 169 and never went back.
  • 1 1
 Only thing I crank is the throttle!
  • 1 3
 According to science or according to "the science"?
Regardless us ebikers have known this for years.
  • 1 2
 Six 5 Mafia

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