Video: The Riders Overlooked By Modern Geometry
Over the past decade, the biking industry has seen a shift towards larger reach values on most mountain bikes, particularly those on the gravity end of the spectrum. While bikes are undoubtedly better for it, this trend can pose challenges for individuals on the extremes of size who still seek the same performance as their peers.
To best cover this topic, I chatted to Pinkbike's own Jessie-May Morgan and Ben Cathro, riders who like her often sit outside of the typical sizing range, to understand not only why they love the bikes of 2024 but also what they would like to see improved upon in coming years.
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I'm in the SF Bay Area, and outside of a few places, trails have not changed much in 20 years, and XC bikes are still what gets the job done in a majority of trails around here.
One example, Canyon Spectral. The 2020 version had a 66 deg HTA, perfect for upper midwest/east coast riding. Current one has 64 deg HTA. It's an entirely different bike now.
nsmb.com/articles/nobody-actually-knows-what-theyre-doing
Personally, I like that there are choices, if you want an aggressive 140mm bike for your riding style and terrain, I'm glad they exist, just like I'm glad the yt izzo and dozens of other bikes exist for my local, undulating, xc trail network spotted with some bigger features.
No argument that a bigger front wheel makes things faster, and easier...
But I know I'm not the only one who got hooked by mountain biking for the technical challenge and jibby good times. Strangely a lot of us could be in this just to have fun, not win races or the dissociated egotrip of KOMs. If we want maximum absolute speed and technically easy we can always go for a gravel/ road ride.
The "Bikes are great, There's so many options, Just ride and be happy" argument has obvious validity -- EXCEPT for the perpetual trail dumbing effect of slacker longer bikes and their "heroic trail work" peeps that keep straightening out legacy singletracks - instead of building their skills, learning how to corner, and considering there are plenty of straighter trails to ride mach 9000 mini DH bikes on without castrating the rare twisty sinuous gems we have left.
SCOR 4060 ST has a 65.5 in the steep setting and that's a 150/140 trail bike.
What I DID notice was an uncomfortable amount of wheel flop on slow speed steep tight corners (guess that's the slacker HTA, bigger wheel, and maybe different offset?). Also noticed a lot of BB and pedal strikes.
The newer bike was a ton of fun at speed on flow, but really didn't impress much on steep chunk and more "natural" trails.
If they can only afford to produce 2-3 frame size options, they're going to be the most popular
The three main choices when choosing their sizing:
1. High tooling cost with small steps between sizes, covering the core size range.
2. High tooling cost with large steps between sizes, covering a larger range.
3. Low tooling cost with large steps between sizes, covering the core size range.
This particularly applies to molded carbon frames due to high tooling cost; it's less expensive to experiment with sizing when using lugged or welded construction. Modular inserts can reduce the risk to the company and add a feature for the customer.
She is on an Epic and Stumpy right now. She's set for a little bit now that I think I've talked her out of buying a full suspension XC bike :lol
A rider that applies half the load to the bike should be on a bike that weighs about half as much. Similarly, huge riders need to accept commensurately hefty bikes. It's wild to hear a rider rationalizing that since they weigh fifty or a hundred pounds extra, they need the lightest possible bike to help them on climbs.
Fun on the DH though.
“29 wheel in the front!!” “High rise bars!” - I’m 5’1 with a short inseam. With these long stack heights, I don’t even know how I could get front wheel traction and good climbing position with a 29er in the front. In fact, I switched to flat bars on my enduro bike (gasp) and I felt like I was pushing into corners waaaay better and felt more “in it” in steeps.
“Full 27.5 doesn’t roll as good!” - idk, the full 27.5 really has its advantages in steeps and jumping to prevent buzzing my butt. I roll over rocks fine. I don’t understand why the industry is so hell bent on the 29 narrative.
“Long chain stays! Stable!” - I find confidence and stability in being able to maneuver my bike quickly to where it needs to go with the shorter chain stay, but maybe it’s because I’m small and weak.
am I way off the mark or do my short friends relate?
That’s said, buy the size that’s right for you and don’t worry about the sizing labels. As a rule of thumb, I think RAD sizing is great, but I’m not an absolutist — I feel like for me there is some wiggle room if it’s slightly longer.
Bar height.
Using the bottom of the pedal stroke as a gauge is just a starting point that happened to work well for the average person on 170-175mm cranks. Actual data-driven bike fits use many more factors than that, including knee flexion at top of the pedal stroke (is less with short cranks, should you lower your saddle to match this?), total knee extension difference (much less with shorter cranks, a good thing), and more. The very common KOPS metric is done with the cranks horizontal, when the crank length has _nothing_ to do with the saddle's vertical distance from the pedals.
Either way, if you shorten your cranks, at least just ride them a few times without any saddle height change. Maybe you'll want to raise it, as everything fit-wise is personal, but very likely you won't feel a need to because the power stroke is at the same height.
I'm also not saying you should never change your seat height, just that a blanket statement to always match the crank length change with an increase in seat height is stupid. Try it as-is first, try half way if you don't like it, try all the way if you still don't like it.
Same with the usual blanket statement to decrease chainring size: just try it first!
I initially followed the stupid recommendation to raise my saddle 10mm going from 170mm to 160mm cranks. I hated it, because my power stroke was 10mm out of position. Lowered it 5mm, felt better, but still didn't like it, and I ended up pretty close to exactly the same, maybe 2mm higher. But not _because_ of the higher bottom stroke, rather because that height feels optimal for the power stroke and having a higher bottom stroke _allowed_ me to comfortably raise it a bit.
Exactly why the "raise your saddle the same length as you shortened the cranks" is stupid! It doesn't take into account anything else. As you said, it "allows" changing saddle position, but I'm also saying it shouldn't dictate it.
And yes, you should.
I'm NOT saying you or anyone is wrong for your preferred saddle height regardless of crank length, I'm saying it's stupid for anyone to say the saddle raise should be automatic with shorter cranks, which goes along with "shorter cranks [automatically] means higher saddle to help counter tall stack" from the OP. It should be "shorter cranks _allow_ a higher saddle if needed to counter a tall stack", and that's all I've been saying the whole time.
I did not say your wife should lower her saddle back down, nor that she's wrong for raising it, just that I think she, and everyone, should have try with it at the old height first. And that everyone should stop insisting that the raise has to be done: it's just another option that shorter cranks open up, not a necessity.
For a long time, every single person had 175mm cranks. Guess that means no one should have ever tried shorter ones..
I just don't see how moden geo has made anything worse, especially when adjusting for small brands that simply don't make smaller sizes and their mediums and larges might have "too much" reach even if they do have a viable seat post height for shorter riders. But again, that's not the geo's fault. That's just capitalism failing a minority group.
Yes, perhaps you don't have the perfect option, yet. But you _definitely_ have better options than before.
But, it is not enoying enough for me to go the custom geo or, Atherton route.
Nevertheless, an ML Madonna v3 for example, would be highly appreciated!
Unfortunately, they’re expensive and got headsetcablerouting
On another note, every time I see Christina ride, I think, “Man, her bike looks too big.” That’s not a personal knock. Now I understand.
That's just, like, your opinion, man.
15 years ago you would have said a size large shouldn't have a 450mm reach, it's all relative. Plus, I think we've gotten to the point where the names of sizes shouldn't matter. It's not whether the size "small" fits you, it's whether there is any size with a reach (and any other geo specs) in your preference.
It's also interesting that Christina mentions that maybe the size small isn't "thought out" as well. I think smaller sizes actually benefitted more from prior trends than the largest sizes. Slack seat tube angles (absolute and effective) gave tall riders a greater disadvantage by hanging their seat way out back to get the seat height they needed. Sure, shorter riders might not be able to fit their maximum chosen dropper, but that complaint is still happening for a decent chunk of bikes in the middle sizes, and at least they're relatively centered on the bike compared to the talls would have been.
Same for size-specific chainstays (and seat tube angles): these _really_ help the XL and XXL riders since with silly shirt chainstays they end up in the back seat automatically, requiring more effort to weight the front-wheel relative to a size with a closer front-center to rear-center ratio. Riders on smaller sizes already benefitted from the race to tiniest chainstays, what hurt though was the need for 29 everywhere, limiting the chainstay length minimum to something often sub optimal for a size XS. Are mullets "modern geo"? Because they definitely helped here, allowing size-specific chainstays to both grow _and_ shrink.
What I want to see a lot more of is adjustable headsets and chainstays so people that don't land square in the middle of the size charts can actually dial in the fit.
I've demoed M and L sizes of the same frame back-to-back a couple of times. You can definitely ride either one and be just fine. So really, we are being catered you. You could toss a coin and be ok either way or you can pick the one that caters to your preferred riding style and body proportions (legs vs torso).
I used to ride mediums because I liked the quicker handling of the shorter wheelbases. Then I injured my shoulder and found that the longer reach/wheelbase of a large helps me keep the front wheel in front of me.
When you're right in the middle of the size range, sure you might "know" exactly which size the manufacturer thinks you should ride. But I think the choice of being between sizes is better.
:: cues up "Freedom of Choice" by Devo ::
Most brands and models, I go large. On certain brands (Yeti, Pivot’s Firebird 29er), I go medium. Guess a test ride for everything is in order.
Obviously the MTB world is massively dominated by male European and North American riders but that doesn’t mean there aren’t plenty of riders for whom average height is a lot less.
(This size issue is seen across many many industries, including things like crash test dummies for car safety testing…)
I’m not sure if the 78° seat tube angle and subsequent forward seat placement is better or worse. Where I live I can be on trails before I’m properly warmed up and I’ve started getting hamstring cramps on the first short steep climbs. Never happen with a further back seat position. But it might be an age thing too being 66 now. Mt take on a further forward seating position is that it helps tall riders not loop out when climbing a bike with short rear centre. It just puts their centre of mass a bit ahead of the rear contact patch. While that may be more efficient in one sense, it might be less efficient in an ergonomic sense because if the seat is further forward, one will be sitting more upright.
I also prefer dual 29 wheels for the better rolling. I did a short experiment with a mullet on my hardtail. Back to back on a 30 minute loop that climbed and descended. Twice. I couldn’t tell the difference. Sure I scuff my butt sometimes but it’s never caused a problem. I do have long legs for my height though. Crotch to floor is 31 inches.
It took me a bit to adapt to the longer bike climbing the Legacy Climb in Squamish. I had no issues with my old Chameleon hardtail or my medium 2019 Remedy but I was having issues on tight corners with the longer more slack Fuel ex. But I have adapted now. And the new bike descends a bit better too.
The best quote I heard about bike fit and this would apply to geometry as well, "It’s a spider web. You pull here and it changes somewhere else."
Half the video has Ben Cathro talking about his difficulties with fit and durability. No offense to Cathro, he’s an excellent rider and I enjoy watching his tutorial videos with my wife who is learning how to ride, but at 6’7” he’s at 99.969 percentile male height in the UK! It would be downright irresponsible for a bike company to spend its limited resources to build a production bike to fit someone so far out at the end of the bell curve. Sorry Ben, you’re going to struggle with fit on production bikes just like you no doubt have trouble fitting in some standard size vehicles and furniture. Ben would be best served going custom. His opinion however, does not belong in this discussion.
What needs to be communicated is that the industry has forgotten a huge portion of potential customers. A 5’4” woman is 52.8 percentile in the US. That means 52 out of 100 women are shorter than that…shorter than Christina. That the author is having trouble finding appropriate bikes at that height, wtf are shorter riders supposed to do? Indeed I’ve seen ladies struggling on XS framed 29 bikes that are too long and slack for their fledgling skills and body size. So the industry is saying half the potential women riders need to spring for a custom frame?! And oh by the way here’s a bunch of geo numbers for you to learn without context because we failed at our job to optimize around known human factors.
From my standpoint, I also feel left behind. At 5’9” I’m at 45.9 percentile in the US. I have the ability and desire to ride a 160+mm bike on all trails but there are hardly any available now with 27.5 front and rear wheels; nearly all have at least 29 front. While I get along fine on 29 up to 140 travel, any more travel raises the stack and standover to unacceptable heights. So I bought one of two identified options of full 27.5 160+ frames that had reasonably designed suspension 6 months ago. In a size medium, it was so long, low, and slack that any ride that wasn’t straight up and straight down was not fun. I ended up steepening the head angle 2* to 65 to liven it up on singletrack but it’s largely uninspiring still. For some of us it’s about fun, not strava times.
At more than 3 decades of riding, I know what works for me but nothing is currently being made. I have to go custom too. And 45 out of 100 guys are shorter than me! While I feel for all who are going through tough times in the post COVID bike industry, I can’t help but think they also brought it on themselves by building only trendy bikes for racers that don’t work for the average rider.
Also, if you're letting wheel size or frame storage dictate your choices, either solely or simply above "correct sizing" and riding style", you're an idiot. If you put them in a poll, it kinda shows that your think your readers might be idiots.
Anyone who prioritizes storage cubbies over fit (which includes riding style) is doing it very wrong, and no one should be listening to them.
I know bigger wheels make smaller sizes awkward in some cases but a lot of brands make smaller sizes 27.5 rear for that reason.
Its good business sense to build bikes that fit the majority of riders the majority of the time. Its a race to the middle. The bell curve of rider sizes points directly toward how much time and effort is put into the geometry and fit of a new model. I WANT to see the same conscious effort put toward the extreme ends of the size spectrum, but its not practical to spend that R&D budget on the lowest sell-through.
TL
Round here most tracks are like a bridleway with super steep climbs and long mellow descents.
At 5’3, 130 pounds, I’ve always had to custom tune shocks and forks to get it feeling right.
Unfortunately, being at either end of the spectrum means spending more money if you want the perfect setup. I realize not everyone is picky, but I can’t put the toothpaste back in the tube…
Surly Krampus with a 69° HA
Stooge MK4 with a 66° HA
Ragley Bluepug with a 63.5° HA
I enjoy riding all of them and ride them all on the same terrain.
Do I have a point? Not really. Just that bikes are good and we shouldn't get too hung up the minutiae.
Maybe we need xs size about 400 reach like commencal does. Forbiden supernought is 420 with reach adjust will bring to 413. That or mullet and older frame like 2017 jedi to reduce reach with angle headset.
Just like sizing a bike only via reach and ignore everything else there should be more guiding how different body proportions affect size and component choice. I'm a tinkerer, I figure it out myself by constantly testing enw stuff, but there are many people who don't have the money and/or time to do this.
For example, I have a 2020 Bronson with as set up reach of 436 and a 2023 nomad with as set up reach of 452 (both mediums, stem lengths almost exactly the same). The bikes clearly feel overall different on the trail but I can’t say I can clearly feel the reach number when riding.
What would be really handy would be bike reviews being done on more than just the one size (usually a L, sometimes a M) with generally the same size testers. Yep, it's a lot more work to test two or three different sizes of the same model with two or three sets of testers to see if they scale properly or if the smaller/larger sizes are severely compromised, but without that, there's just not a lot of value in a review for a person who's NOT 5'10" and 170# (and no, comments on "size specific chainstay length" don't make up for that).
Some bikes tend to scale really well across the range - there's a lot of thought given to size specific suspension tunes, slightly different STA, appropriate stack height, maybe size specific rear triangle length. Others scale horribly.
Give us Grim Donut content please. We want and need it. That bike is a celebrity without any negatives.
Also well done on this vid @christinachappetta
Informative and interesting.
it's much better to ship a bike with bars much too wide than a little bit narrow, because only one of those problems is fixable without $$.
If that is what you really want to happen, you should just lie on the poll.
Pretty sure the PB poll and comment section isn't on the radar for these guys.