Opinion: Why Is Everyone Talking About Seat Tube Angles?

May 9, 2019
by Mike Kazimer  
Spinning Circles column Mike Kazimer

Seat tube angles. A few years ago they were barely worth a mention in a bike review, and now entire paragraphs are being dedicated to a seemingly minor geometry figure. What gives? Are bikes so good now that reviewers are obsessing over details that barely matter? Not exactly. To set the stage, let's go over the changes that have happened over the last decade regarding bike fit.

There was a time when bike sizing was almost solely dictated by seat tube length, similar to how road bikes are measured. You'd figure out what length seat tube allowed you to show just the right amount of post and call it good, maybe going with a longer or shorter stem to fine tune the fit. It was the arrival of dropper posts that really started to shake things up – seat tubes no longer needed to be as long, and riders could easily fit on multiple bike sizes, especially in more recent years as posts with 170 and even 200 millimeters of drop have hit the market.

With seat tube length no longer as relevant, and shorter stems paired with wider handlebars becoming the norm, a new number started appearing in geometry charts: reach. If you draw a vertical line upwards from the bottom bracket, and then measure from that line to the center of a bike's head tube, that's your reach number. It's a way to get an idea of how a bike will feel when you're standing up out of the saddle – your typical descending position.

I've heard people say something along the lines of, “Reach is the only measurement that matters,” but that's not really the case, especially if you're planning on spending any time sitting down while you're out on a ride. Reach is a useful number, but a bike's effective top tube length is still worth paying attention to when trying to figure out what size bike to go with. Due to the range of seat tube angle measurements, it's entirely possible to have two bikes with the exact same reach number, but with very different top tube lengths. That means that while the bikes may feel similar while standing, your seated climbing position could be extra stretched out on one, and almost cramped on the other.

Whyte S-120 review
Pole Machine review
The Whyte S-120 and Pole Machine have the same reach number, but the seat angle gives them very different seated pedaling positions.

For instance, take the Whyte S-120 and the Pole Machine. Yes, one's a trail bike and the other's an enduro monster, but put that fact aside for a moment. A large S-120 has a reach of 480mm, the same as a medium Pole Machine. But when you look at top tube lengths, the Whyte measures 640mm, while the Machine measures 607mm. That's a big difference, one that's immediately noticeable when you're sitting down and grinding up a hill, and it's created by the fact that the Whyte has a 75-degree seat angle versus the Machine's extra-steep 79-degree effective seat angle. There's also the fact the Machine's actual seat angle is quite steep as well, at 78-degrees.

Before we go too deep down this rabbit hole, it's worth pausing for a minute to go over the difference between actual and effective seat tube angle. Effective seat tube angle is what you'll typically see in a bike's geometry chart, and it's calculated by figuring out the angle of a line running from the center of the bottom bracket to a certain saddle position, typically one that's parallel with a line drawn horizontally from the head tube. Of course, that saddle position isn't going to be the same for all riders, and the effective seat angle is going to get slacker the higher the seat gets, but it's a point of reference, a way to compare apples to apples when looking a multiple bikes' geometry numbers.

The Commencal's actual seat angle is 66-degrees, but look at where the seat tube is positioned. When the seat is fully extended it has an effective seat angle of 76.5-degrees.

Actual seat angle is just that – the angle of the seat tube on the frame. It's useful because it makes it possible to get an idea of how much the seat angle will change as the post is extended. On the aforementioned Pole, the actual seat angle is 78-degrees, which means that the starting vs final angle of the seat doesn't change all that much, while on the Whyte it's much slacker. So why not skip using effective seat angle altogether? Because not all seat tubes start from the same point in relation to the bottom bracket, which means the actual seat tube angle isn't as useful in figuring out what your pedaling position will feel like.

That brings us back to the original question – why is everyone obsessed with seat angles all of a sudden? It's pretty simple, really. Bikes have gotten significantly longer over the last few years, and pedaling around a long, slack bike is much more challenging if you also have a slack seat angle. Slack head angles = good. Slack seat tube angles = not that good. A steeper seat angle puts you in a more centered position for climbing, and it's easier to shift your weight forward and backward as needed, compared to feeling like you're going to loop out any time you start climbing. Of course, you can have too much of a good thing, and really steep seat angles can make a bike's cockpit feel too cramped, even if the reach number seems long. Sliding a seat forward or back on its rails is the obvious solution for fine-tuning a bike's fit, or going with a slightly longer or shorter stem, but there are limits to both of those methods.

It can all seem overwhelming, but it's not worth losing sleep over trying to decide which size bike you should buy. Studying geometry charts and brushing up on the relevant terms will only take you so far - the next step is to attend demo events and test ride whenever possible, ideally trying both sizes if you're not sure which one will be the better fit. In the end it all comes down to personal preference; just remember to make your decision based on what works for you and your riding style, not what someone in a bike shop or on the internet decides is best.


376 Comments

  • + 136
 Additionally, steeper 'actual' ST angles = better loading of dropper posts. Compression force is more in-line with post movement so less binding/friction.
  • + 37
 having absolutely ruined the bushings in a reverb by running it on a bike with a 61 deg actual ST angle, i can whole heartedly agree with this.
  • + 278
 @inked-up-metalhead: The reverb destroys itself naturally, you probably didn't do it.
  • + 14
 @Dlakusta: 18 months on one bike with a sensible seat angle and it was fine, 3 weeks on the other and it was knocking like hell and you could physically move it front to back about 2mm at the seal head. pretty sure it was the stupid angle it was at.
  • + 6
 @Dlakusta: Pinkbike doesn't know how true this is....
  • + 8
 @inked-up-metalhead: probably the straw that broke the defectively designed camel's back
  • + 10
 Dropper on the Pole I have is smooth as buttered eels, zero binding. Always used to be ‘kind’ when dropping the post, don’t have to pay much attention now.
FWIW, I’ve found the 79 sta to be super comfortable and natural feeling.. you’re in a position that makes you want to climb. I let other ppl demo and they said the same. At the end of the day, that Machine climbs well beyond a class of what it should on paper especially considering the weight, HTA and travel.
  • + 12
 @g123: Yup I agree %100. My Pole is a fantastic climber. The only thing that sucks is taking pics of it because it looks so goofy lol
  • + 7
 @g123: my canfield riot is almost as steep and at 6'3" with long legs climbing is a joy instead of misery for my back. I would love to ride a pole some time... hehe
  • + 2
 @gunnysun: I actually had a Riot before my Pole. Agree it did climb decent as well and coincidentally they have similar suspension designs. At 6'4" I found the Riot to be way short however whereas the Pole fits like a glove. Way more comfy.
  • + 1
 @Dlakusta: hahaha...so true
  • + 0
 @inked-up-metalhead: Mines as flawless as can be on my sb130,since inception
  • + 3
 I don't know enough about the internals but does no one make a dropper similar to a Lefty with roller bearings to better deal with 'side loads'?
  • + 2
 @DuncanCT: Man. You have uncovered the next marvelous disruptor that will once again change the MTB world.
  • + 3
 @xeren: that's why you shouldn't have a non-cable actuated camel. Or straw.
  • + 1
 @bohns1: SB130 is actually one of the few modern, 'mass produced' bikes with a fairly steep actual seat tube angle. So props to Yeti on that front. I'm not a fan of carbon only frames and the Kashima rails, but hey, a step in the right direction.
  • + 1
 @DuncanCT: Given the drop amount of the seat posts and their overall length (and weight constrains as well) I'm not sure it would turn out as well as you're hoping...
  • + 1
 @Primoz: Only kashima on my yeti is the rails ..Other than that and a gold xx1 cassette,she's blacked .
  • + 1
 @bohns1: The Kashima was not a negative in itself, i'm not a fan of non-standard parts. Sourcing the rails and the bearing carrier might be an issue (more so in Slovenia i'd think). But hopefully this is not something that will explode overnight like a bearing could (not seeing the damage soon enough for example). That's my gripe. That and carbon-only-related-pricing and equipment spec for the price (GX cassette on X01 named equipment level), but most major brands do that anyway...

But without nitpicking (i'm really good at it, sorry), it seems like it's a really good bike, both SB130 and 150.
  • - 2
 I'm on a hardtail. Practically 90* STA. woop woop, beat that Pole. Razz
  • + 1
 @Tmackstab: are you talking about your bike?
  • + 1
 @mtbikeaddict: The almost 90° STA, Url to the bike please, i'd like to see it Smile
  • + 1
 @Primoz: This is why I always do frame only...Been in the game long enough that it's usually just swap parts over from previous build and go from there..
  • + 1
 @Primoz: Ah, now I get it. URL pls, two separate, one acronym and one abbreviation, lol poor me was so confused by that jumble. I don't think my bike has a url; too old. It's probably not literally exactly 90*, just seems like it, and... I was using hyperbole. Big Grin I'll see if I can work out a rough measurement or get a pic or something though
  • + 73
 Here's my five dollar bike industry idea. Forward offset dropper posts
  • + 18
 I keep waiting for this too. Everyone riding around with their seats way forward on the rails.
  • + 35
 9point8 just announced a 25mm forward offset post. You're welcome?
  • - 8
flag laksboy (May 9, 2019 at 13:14) (Below Threshold)
 @xy9ine: @ratedgg13 as far as I can tell, that's a 25mm reverse offset, or better known as a setback... You had my hopes up. I'd love to not have my seat slammed all the way forward... (Short femur syndrome)
  • + 10
 @laksboy: They have forward and rear offset options, both in 25mm. - www.9point8.ca/index.php?route=product/product&path=116&product_id=233
  • - 1
 @ratedgg13: unfortunately it's only for their R series post, won't work on their 200mm post where it would be most useful
  • + 8
 @laksboy: what happens when you rotate a setback post 180°? Setforward.
  • + 10
 ... or we could just have steeper seat tube angles until we don't need forward-offset posts or saddles slammed forward on the rails. Any adjustment that's always at one extreme of its range is calibrated incorrectly.
  • + 9
 @mnorris122: most posts don't allow the seat to be flat if the post is rotated. So that works if you like a saddle tip up the bum.
  • + 10
 Here's my $5 Million MTB bike industry idea: forks that allow you to select either 51mm or 44mm offset (like many do on rear dropouts now). Mechanical only though!!! :-)
  • + 1
 I believe 9point8 has just started offering forward offset droppers.
  • + 4
 True, but if you just slam your seat forward on the seatpost, you get a steeper seat tube angle. Instantly a little more modern geo.
  • + 0
 @tacklingdummy: You can do that if your not in the market for a new bike. If buying a new bike anyway I would be looking at seat angles between 76 and 78 degrees.
  • + 1
 @mnorris122: been there, done that. Basically depends on the design. It was my setup in my old bike with no dropper and a Bontrager rigid post. No way in my actual KS droper.
  • + 1
 @mnorris122: a setback post rotated 180 does not work as a set forward post. Stoked to see that 9.8 is doing this for cheap since I already have the post and it's slammed forward.
  • + 3
 @mnorris122: You cant get the nose pointed down enough. I looked into it previously with 9.8 setback post. Would have gone with 9.8 if I knew the forward post was coming!
  • - 3
 Run offset post backwards.

????
  • - 3
 Maybe turn a rear offset post around180 degrees?
  • + 23
 I've saved this pic all these years for just such a comment... Smile

m.pinkbike.com/photo/9048926
  • + 0
 @could’ve avoided that whole issue by binning the horse cock stem.
  • + 0
 @mnorris122:
I have seen that. It works on some droppers
  • - 1
 @mnorris122: you better enjoy having the nose of the saddle very high.
  • + 0
 @xy9ine: Not really because I dont own a frame for the mount. Do you drill your frame? I would not want to lose my warranty...
  • + 3
 The reason lots of bikes have kinked seat tubes, with a slack actual angle is to clear rear tyre under compression. If you had a seatpost with a big rearwards offset, you could just offset the whole seat tube forwards and have tyre clearance without daft angles. Probably marginally better loading on the bushings than a slack inline post.
  • + 1
 @mountainsofsussex:
It would be the exact same loading. Force vectors don't care how they came into existence just that they do exist.
  • + 3
 @stiingya: my taint hurts just looking at that seat angle
  • + 1
 @mountainsofsussex: Exactly. Eightpins offers a setback head for this reason. Frames could return to straight seat tubes.
  • + 3
 How 'bout someone just freakin' makes a saddle where your butt goes in the middle of the rails instead of the back of them? Fizik made one a few years ago called the Thar, but they marketed it as a "29er" saddle and everyone mocked them. They should make it again and call it a "shitty seat angle" saddle.
  • + 2
 @Altabird: Agree in principle. The problem with the Thar is the huge rear overhang, which you couldn't even access with your butt, can contact the tire. Better to frame the concept as moving the clampable part of the rails to the very back of the saddle.
  • + 2
 how about a flip chip or angle set adjustable seat tube with .5- 1.5 degree’s?
  • + 1
 @travmaster3000: Kinda like saddle rails?
  • + 1
 @travmaster3000: Some frames with the flip chip alter the geo slightly by changing the HTA, STA, and BB height, but it is only about .5 degree.
  • + 1
 @tacklingdummy: there are other frames like the Nicolai G1 Enduro. This bike can changed from 61,1 ° HA to 64,4°. Actual STA from 78° to 80,1° and other stuff way more radical than most bikes even come stock and that's not all because the Nicolai don't even have offset bushings for the shock to make it even slacker or a headset cup/angle set for again more slack stuff.
That's also not all because other stuff can also be changed but that's another subject.
  • + 3
 Then the cockpit is too short. For a steep actual seat tube angle you need an 'insane' reach for the bike to fit properly. Here's a daring claim, the Pole actually isn't a long bike, cockpit wise!
  • + 3
 @gonecoastal: Funny how we get donw voted when it's exactly what it is.

I've run Command Posts both ways depending on need, there's no front/rear to a dropper.
  • + 3
 @stiingya: the command post, such as in that photo, can be run with the saddle at any angle.
I used to run my command post like that, worked fine for a long time, still does 7 years in service, many bikes worn out in that time.
  • - 2
 @getsomesy: NO way!! You mean you just turned it around? Not possible it's a rear offset seat post. You can't just do that.
  • + 3
 @TheOriginalTwoTone: you're making fun of people here, but others commenting that it might not be possible have it right. The IRCC Spec seatpost most likely actually does not allow the seat to be level when rotated 180°. Same for Marzocchi's 2015 seatpost and some others (i did a quick Google for offset dropper posts). A two bolt post has a limited range of adjustement, optimizied for rear offset instalation. The Specialized's post that can be rotated have a single bolt head, which has a larger range of adjustment. But people don't really like single bolt heads because when loosening the bolt, the position can move a lot, it's hard to finely tune it. Harder than on a two bolt post where to change the angle you untighten one bolt and tighten the other.
  • + 0
 @getsomesy: Sorry. If you can back that statement up with a picture of a "backwards" command post with a LEVEL seat than I'll believe you. (and maybe you can) Otherwise I'll continue to believe that saddle is ridiculously NOSE HIGH because when the post is backwards you can't angle that seat to level because they weren't meant to! Maybe you ran it backwards and were OK with it? I've seen some post/seat combo's that were close to level that worked?

My "GUESS" is that the person on this bike being VERY tall, was also too heavy for that spring on that shock and the bike probably sank way too far into it's travel. So the super long stem and backwards post was trying to fight against all that sag...??? BUT, it's just a guess...

I almost bought that bike for the coil set up cause Specialized stopped making the aftermarket proprietary strut for those Enduro models. Smile
  • + 1
 @stiingya: the single bolt head posts probably have a much higher angle adjustment range. But the newer ones don't, i agree.
  • + 0
 @Primoz: We'll agree to not agree then. (unless you have a pic that changes my mind?) The pic I linked to does not look like it will adjust anymore level than it is IMO?

Anyway... good, though quick ride today! Smile
  • + 3
 @stiingya: The generation of Command Post shown in your photo had an infinite range of adjustment. I owned one.

Here is a photo of components from a Bontrager seatpost made by the same vendor: www.evanscycles.com/bontrager-single-bolt-rotary-head-seatpost-parts-kit-EV159297

It just uses conical parts that wedge into the seatpost (www.tritoncycles.co.uk/images/bontrager-colour-matched-seat-mast-cap-p19230-87122_image.jpg) and can rotate infinitely.

The owner of the bike you linked must have angled his (or her) seat at such an uncomfortable looking angle by choice, as it does not have to be that way.

The same user has another bike with the seatpost in the intended orientation and the seat appears to be angled upward: www.pinkbike.com/photo/9048998
  • - 1
 @R-M-R: Hmmm, well still not a pic of the post backwards and level? (looked myself and can't find one either?) But as I said, I could be wrong... Smile
  • + 2
 @stiingya: How many backwards posts do you suppose are out there? I can't find a photo because the number is nearly zero.

As an owner of this post, when I released the clamp bolt and nudged the conical pieces to free them, the seat would flop forward or backward into a vertical position. There are no stops.

Maybe the burden of proof is now on the person claiming it's impossible, not the two people who've owned the post in question, one of which has shown you the components of the post that display complete radial symmetry, indicating infinite adjustment range.
  • + 1
 @Primoz: The cockpit is only shorter when seated for climbing. The reach doesn't change so it will feel the same descending.
  • + 1
 @tacklingdummy: How long is your descent compared to your climb? Where do you exert the most energy? Which of the two is then the 'only' part?
  • + 1
 @Primoz: My descent is the exact same as I climb. Both climbs and descents are tough. When pushing the seat forward, it only changes the pedaling position not the reach. Pole's reach is definitely stretch, but the pedaling position cockpit is short because the seat tube angle is so steep.
  • + 1
 @tacklingdummy: I know why the Pole is like it is.

As for the descent being the same as the climb, boy you must be a rocket on the climbs or a really, really slow descender. Notice i meant long time-wise and specifically mentioned energy, i didn't mean the distance or path of the two.
  • + 2
 @R-M-R: Well you have people in this thread saying they ran them both ways...

Anyway, I''ll concede that the command post could run both ways and the angle wasn't an issue. (gawd knows why the seat angle in my pic is like that then...? OUCH!) Usually I don't believe without seeing. But I'll take your word on it.

You'd think with all the Joplins, Bonty, Spec, and original Maverick droppers, (more?), based on that design that a pic showing that adjustment range or at least a mention in a review would pop up in a search? (google skills fail?) I've seen backwards dropper pics several times over the years, most recently on an Evil Following. But still can't find a pic?

Anyway. I think in the end were on the same side that seat tube angles should be steeper? OR should we start arguing about that too!!! Smile
  • + 0
 @Primoz: "As for the descent being the same as the climb, boy you must be a rocket on the climbs or a really, really slow descender."

LOL! Smile ZERO elevation change maybe? Maybe this is proof of the Flat Earth theory that youTube rocket guy was going on about!!!
  • + 1
 @tacklingdummy: wtf? I need to climb my local hill in 35/45 min for 5 km and 500 vertical meters. Descending however I am done in 3/4 minutes. Less km off because - 20% and more gradient.
  • + 2
 @stiingya: Yes, we're on the same side regarding seat tube angles. My philosophy can be summarized as:

1. Much of our time in the saddle is spent on steeply angled terrain.
2. Mountain bikes often have a lot of rear suspension that sags considerably when our weight is shifted rearward on climbs.
3. Geometry needs to prioritize the more severe situations a rider encounters. This may compromise geometry for more mundane situations, which is an acceptable trade-off.

Therefore:

1. Our time-averaged effective seat tube angle is not the number stated on a spec sheet.
2. Seat tube geometry should be adjusted to better suit steep climbs; if the seat tube is steeper than ideal for flat ground cruising, that is acceptable collateral damage.

An evolved version of the Redshift Dual Position seatpost may have potential.
redshiftsports.com/dual-position-seatpost
  • + 1
 @stiingya: zero elevation change doesn't really count as a climb and descent, does it now? And in that case, you're sitting down 100 % of your ride more or less, so reach is even LESS of a factor.

Regarding the Redshift, my friend, who has a PhD from kinesiology now, did his bachelor's or masters degree investigating the effects of a moveable seatpost on climbing performance and efficiency. They had a prototype made, but that was the end of it. Dropper posts would have probably killed the thing anyway and it was intended mostly towards the XC crowd (among the MTBers).
  • + 1
 @Primoz: I thought you meant distance, vertical feet and effort. Lol. I don't shuttle or have a lift access park. Live 30 minutes from Santa Cruz. My rides are 1500-4000 vertical feet, 10-25 miles. Obviously, downhill time is no comparison to climbing. Haha.
  • + 1
 @tacklingdummy: Well there you go. Therefore you maximize the fit and everything timewise, don't you? I mean it's only logical to have the most fitting bike where it actually matters. A few mm on the reach will have less of an impact going down because you're in a much more active position and can adapt more easily.
  • + 2
 @Primoz: Not disagreeing that a good fit matters. Just saying that pushing the seat forward on the rails or steepening the seat tube angle only changes the seated climbing not the reach, so it will not descend different with same reach measurement. To me, any changes on the reach or effective top tube length makes an impact. Those are the two most important measurements for how the cockpit fits and definitely makes a difference on how a bike handles.
  • + 1
 @tacklingdummy: There we go. Reach = horizontal from bb to ht. Basic stuff. When you're out of the saddle/standing/anything physical/demanding/high energy, you're on the pedals, and reach matters, unless you're some oddity who always just cruises way back on the seat lol.
  • + 1
 Like the Command Post I had turned around backwards. Looked goofy, but that's what I had to do to get my butt over the pedals on the Stumpjumper that was too small for me. Being tall I have to settle for bikes too small, and the more slack the seat tube, the more problem it is as the seat is extended so far.
  • + 0
 @tacklingdummy: of course it will descend (more or less the same). But if only descending matters, why not throw out the seat?

Talking about seat tube angles and the pedalling efficiencies the differences cause and then saying 'it doesn't matter going downhill' is... missing the point to put it lightly Smile

As for the reach and ETT, reach is more or less meaningless (which i've said a few times already) since it only tells you a part of the story. 'Normal reach' for a short effective top tube will be horrible due to a short cockpit (Forbidden Druid). Short reach and a long ETT will make the cockpit feel good, but the STA will be slack and the bike will climb badly. I look at the reach number only after looking at the ETT and seat tube angle. To confirm those two things.

EDIT: i went from a 'normalish' reach to an 'insanely long reach'. The bike is much, much better going down. Many people would say it's too long for descending. But it's not.
  • + 64
 "just remember to make your decision based on what works for you and your riding style, not what someone in a bike shop or on the internet decides is best."

Don't listen to this. Get a medium.
  • + 3
 Medium with a Large experience.
  • + 1
 @qreative-bicycle: that’s what the GF gets.
  • + 19
 The article didn't mention rider height at all. Taller riders have been asking for steeper seat tubes for ages. For shorter riders 78' is probably going to be too steep and that's fine. We should be pointing at lazy designers and manufacturers for not recognizing that different people are different.
  • + 9
 I Disagree. Being tall and having a ultra steep seat tube puts so much pressure on my hands and a very uncomfortable position unless Im climbing up a wall. Full enduro bike sure...but an trail rig...no thanks. And I don't want a crazy front end stack height just to feel better on the climbs. Having a slacker seat tube allows a shorter chain stay without a super long bike. So many Enduro bikes these days are race machines not trail rigs but the geo is running over into the trail market.
  • + 5
 @Trail-Gnome: And a slack seat tube puts your ass over the rear axle. No bueno.
  • + 5
 It clearly states that eSTA is a function of riding position.

"[Of course, that saddle position isn't going to be the same for all riders, and the effective seat angle is going to get slacker the higher the seat gets [...]"
  • + 5
 @ReddyKilowatt: Big bikes aren't big enough for big riders. Put a tall guy on a bike with over 540 mm reach and it's a revelation, every time.
  • + 2
 @velocitajano: eSTA gets slacker as the saddle gets taller. That's why a steeper STA to begin with is beneficial for a tall rider that needs a super long seat post. But then to get proper positioning over the pedals the seat has to be slammed forward, but often won't go far enough. So, tall riders struggle to get a comfortable fit.
  • + 4
 Agreed this isn't new, I've been analyzing seat tube angles for years. Learned that after I tried an early evil and had to sell it since the actual is so slack that when raised up for my 6'5 legs I couldn't ride flat ground without wheeling out. Simple thing is bikes need to change geo according to size, stack should come up and seat tube should steepen for an xl. Things are definitely vastly improved with the reach but there is a lot of room for improvement on large frame bikes for large riders.
  • + 2
 I’m tall with long legs and the slackness of most effective seat angle puts me way off the back of the bike, even with saddle slammed forward. Also note how many bikes have steep effective angles but slack actuals (avoiding tyre rub of 29” wheels with short chainstays?), penalising long-legged types who run seatpost heights waaaay above the line where effective angle is measured. Steeper SA is a good change for me!
  • + 2
 @Trail-Gnome:
I don't see your theory that it is hard to have short chainstays, long travel, and slack seat tube angles.

Look at first gen evil the following, the wreckoning and the insurgent. Short rear ends, and stupid slack seat angles. As a tall guy I couldn't climb much of anything while seated on those bikes as the front would pull off the ground so easily.
  • + 1
 @Chris97a: I have never had that issue on a wreckoning but we all have different styles and preferences for sure. Does that crazy steep seat tube angle and helps you on that really steep climb worth the rest of the time that your riding on a unicycle feeling seat tube? Like cutting your bars down for that one skinny tree section. As mentioned above by someone, it really depends on your riding conditions. I appreciate my steep seat tube on my longer travel bike that Im sitting for an hour climb before descending, Also take in account more travel=more sag=several degs of seat tube angle change. But when Im going out for a long mix condition trail ride with tons of spinning I'll take my shot travel bike with 73 ST all day long. My hardtail has a slack ST but with a 140mm fork and no rear sag the seat tube gets steeper with sag.The wonderful thing is just as different as peoples riding geo preferences are so are bikes geo. Its good to have choices, there is no one fit for all but when Im just seeing a lot of "steep STA are the only way" without a lot of thought.
  • + 4
 @Trail-Gnome: "Its good to have choices, there is no one fit for all but when Im just seeing a lot of "steep STA are the only way" without a lot of thought."

That's largely because those of us who prefer a steeper seat tube angle haven't had any options. Now we do and we're ecstatic.

I agree with you that the problem largely came from maintaining traditional 73° seat tube angles as bikes gained rear travel, which inherently squats on climbs.
  • + 2
 @Trail-Gnome:
Perhaps the answer lies back in 1995 with one of the first remote adjustable seatposts.

The power post extreme had a climb setting which sat the rider forward at the push of a button.

What is old is new again.
  • + 4
 @Trail-Gnome: Does that crazy steep seat tube angle and helps you on that really steep climb worth the rest of the time that your riding on a unicycle feeling seat tube?

Guess it depends where you live. I can't really think of a trail near me that I would ride a long-tavel bike on that doesn't have at least a 1/2 hour climb where a steep seat angle helps a ton. We don't have many green climb trails here like some other areas have, so you gotta ride up to get to the descent. I'd say 80% of my pedal time is spent grinding up steep ass grades. There are certainly flatter, tamer trails with less steep climbing, but they also have less descending, so no reason for a long-travel bike on those.
  • + 3
 @dthomp325: DITTO! Most of the time spent sitting and spinning is when your grinding up a climb. The up/down/flowy stuff your in and out of the saddle and moving around on your bike so much that getting some kind of K-pops/perfect center seat/etc. is a lost cause. So it makes the most sense to optimize your bike for big climbs and big decents...

ALSO, there are lots of set back dropper posts out there, so it's easy for someone to size down and use a set back "if" for some reason they spend most of their time riding on flat terrain...??? (bummer)
  • + 2
 THIS!!! SO MUCH THIS!!! Different seat tube angles (actual ones!) for different sizes. And different suspension geometries to adjust the antisquat values to different sized people, since an XL rider will have the CoG (and the 100 % antisquat level) higher than an XS rider.
  • + 1
 @Trail-Gnome: My latest bike has a steeper seat tube angle, and while it's amazing to not have my ass over my rear axle when climbing, I totally have to agree with you about having too much weight on my hands. Despite my newer bike being 50mm longer than my last one, the cockpit feels only a tiny bit longer. The steep seat angle brings my upper body closer to my bars, and I'm leaning down onto them. Hence, after an hour or so on the bike my hands are sore and fatigued. Basically for us tall folks my theory is if the bike you're looking at buying didn't increase the reach by 20mm more per increase of seat tube steepness, then it'll likely be too short in the cockpit.
  • + 1
 @gbeaks33: Yes, that can be a consequence of steep seat tubes if the reach and/or stem doesn't increase enough to compensate.

Reach measurements may need to increase well beyond where they are now, which will probably mean steeper head tube angles and longer chainstays to maintain a manageable weight distribution.

Bike designers have surprisingly little time to test each revision of a bike, which rarely leaves enough time to test every possible variable. We often see changes made in a stepwise manner and some consequences of prior changes have to be addressed in the next model update. It's the unavoidable trade-off between R&D thoroughness and bringing the product to market quickly enough to not go bankrupt!
  • + 3
 @gbeaks33: I was eaten alive when I said Forbidden Druid is too short since it has a steep seat tube angle but a normalish reach. But it's true
  • + 1
 @Primoz: At least the seat tubes are short, so a person can size up.
  • + 1
 @R-M-R: But you can't go anywhere up from the XL...
  • + 2
 @Primoz: Stop being so tall.
  • + 17
 The big question in my mind, is whether anyone is adjusting traditional bike-fit programs to take advantage of this. A bike fit is going to put the saddle at a specific location relative to the bottom bracket. If the seat tube angle is steeper, the saddle would simply be slid farther back on its rails and vice versa.

I understand this new philosophy as simply being maintaining KOPS but at certain grade rather than flat, but is there any new consensus on how bike fits should be carried out to take advantage of this. Like doing a bike fit at a 3% angle or something? If we're not changing bike fits, than steeper seat tube angle doesn't really change anything.
  • + 7
 Very good questions to raise. I think part of the answer is that this new philosophy isn't looking at KOPS on a grade so much as moving away from KOPS as a bike fit parameter
  • + 31
 bike fitting is like ski boot fitting and essential oils. Pseudo science thats hit or miss.
  • + 5
 There is literally no actual scientific reason to fit the knee over pedal spindle on a mountain bike. You can read my collection of articles for my thesis if you’d like. Smile
  • + 8
 @andrewfif: Keith Bontrager beat you to it by a couple of years ????
  • + 15
 @hamncheez: As someone who has had overuse injuries from poor fit, and am more efficient and healthier because of a fit, I disagree with this. There are different interpretations, but it is not snake oil. I agree that bike fitters should be thinking about how these new seat angles affect their methodology. A good fitter is not a dumb person. They will adjust and keep us riding strong.
  • + 74
 @hamncheez: Pseudo science?! I replaced my suspension oil with essential oils and I've yet to crash. My shock and fork also smell great, and newts are resurrected immediately after I roll over them on the trail. Magical stuff.
  • + 12
 The other thing you must factor in with this conversation about fit is dynamic sag-this also changes the SA angles-both actual and effective. Makes the Shockwiz super useful for a full suspension fit... Before I'll ever do a performance fit on a full suspension bike for a customer I send them out with the shockwiz for a week so we can get the dynamic sag numbers and use that to set up the bike appropriately. I was stoked when I realized that possibility.
  • + 10
 @tlilly: anecdotal does not equal evidence
  • + 8
 @TucsonDon i had this same question a little while back to mike. People have to be adjusting their traditional fit to take advantage of the fwd seat tube angles and my question is does this start to put more and more people into poor bike fit and eventually leading to knee problems(if you shuttle/lift all day or dont pedal much then doesnt really matter). At least for me i have found the extreme. I am 5'6" with a 30" in seam on a small transition sentinel that has a 77.5deg effective seat tube angle. I have started having knee problems since riding this bike. Cant say if its for sure the bike or just overuse. But even slamming the seat all the way on the rails i can not get my knee cap into the traditional position over the pedal spindle with a 140-150 knee angle at extension. I will likely have to go to an offset dropper to get there. I think being in a more fwd riding position for the steep sections is such a short portion of most peoples ride Id much rather be in a position that puts my body into longevity for all the pedaly bits and not just have a slight advantage on the steep pitches. Again i cant say for certain that the new seating position is whats causing my knee problems but at least for me i will stick to the more traditional seated position for my knees.

Also my conspiracy theorist is we have all these steep seat tube angles cause thats what you have to have to package a long travel 29er with 2.6" high volume tires with reasonable chain stay lengths. Putting you more fwd in the seated position is just the by product of the packaging constraints. My sentinel has zero clearance at bottom out, they had no choice other than a steep seat tube.
  • + 7
 I think any discussion on bike fit regarding seat position needs to reference Steve Hogg’s writing on it with regards to balance point:
www.stevehoggbikefitting.com/bikefit/2011/05/seat-set-back-for-road-bikes

Now, that’s just one of the articles he wrote on it and it is focused on sliding the seat back to balance for a low stretched out aero position on a road bike, but the inverse is also true. You raise the front and shorten the stem for better bike handling and more fork travel into a more upright position, the seat must come forward to maintain balance.

I think what we are now seeing with SAs is just a realization of the fit principles Hogg wrote about years ago, just flipped for current long travel mountain bikes.
  • + 13
 @davidsamuelhu: really depends on your terrain. Here in coastal BC it's often straight up and straight down (whether fire road or single track) so steep SA is awesome for climbs, not much flat/up and down stuff. In a place with flat/rolling terrain and lots of flat pedaling then yep stupidly steep SA is going to be feel bad over time, but then I would wonder why people in flat terrain are buying super aggressive enduro bikes which are the ones with steep STA.
  • + 2
 @whambat: road bike fit and mountain bike fit isn't really much different, the geometry is just slightly different. My road bike and XC bikes are set up pretty similar, and if I got a long travel bike I would set it up with the same saddle position relative to the bottom bracket. I don't know why people think bike fit is really all that different between mountain bikes and road, it's the same position with different geometry.
  • + 4
 I think traditional bike-fit programs have become somewhat outdated since over the last few years the majority of riders have been going with much longer bikes. The steeper STA helps keep the top tube length in check so you can go longer without being uncomfortably stretched out. I'm really liking the new Jeffsy geo, long reach but short top tube due to the steep STA. IMHO, it changes everything.
  • + 3
 @Bob12051968: the steep STA simply moves the rider forward to compensate for a long front center, it doesn't change anything. You're still putting the rider in balance over the bottom bracket.
  • + 4
 @watchmen: He sure did, but somehow the method persists. He didn't prove that you shouldn't do the KOPS fit method, just suggested that it isn't the same thing. I didn't even actually study this specifically, but Borut Fonda did some excellent research in this area.
  • + 4
 @clink83: I used to think that way as well. Then I tried fitting based on a balanced position as Hogg describes and now my bikes fit based upon balance. Surprisingly, it feels similar from bike to bike, road to xc to long travel, even though the positions related to saddle to BB are different. My road fit is near flat back with a slammed and my enduro is darn upright. If you are in the middle or getting near a competitive season, don’t try it, but don’t knock the concept until you do, just wait until the off season. Meanwhile, my 160mm forked 29er (Ripmo) climbs like an XC bike because I have balance on the front because I have a 76SA and get no lift of the front wheel. Yes, I can have the same balance in a 73 SA XC bike with a longer and lower handlebar position, but you end up in a compromised position for DH. And KOPs is thrown completely out the window from road to mtb since the climbs are measurably steeper with far less seated pedaling on downhills. A 73 SA on a mtb is like a 70 SA on a road when you factor a climbing pitch as your hips are way further back in relation to your BB.
  • + 10
 Without getting into the other issues, I'll just say KOPS is a coincidental relationship and should be ignored. If it had merit - i.e. a position that placed your knee not over the spindle was bad - then recumbent bikes should ... I don't know, cause your knees to burst into flames. But they don't.
  • + 4
 @hamncheez: At least with plug ski boots it is not a pseudo science, just a matter of remolding the whole boot to your foot.
  • + 10
 @whambat: as soon as you said your ripmo climbs like an XC bike I stopped listening. It doesn't.
  • + 3
 @clink83: There should be a +10 upvote button purely for calling out the 'climbs like' trope.
  • + 2
 @hamncheez: too true but it is also a great way to dupe a noob out of a few hundred dollars thus helping keep your LBS afloat ...especially if said noob needs a new reverse offset Carbon post and a shorter stem.
  • + 7
 @gramboh: Right on. Different horses for different courses. And to think that super steep STAs have no drawbacks is foolish. There are pro and cons to everything. Biggest fix to this issue is to avoid being over-biked. Short-modest travel bikes don't sag that much on climbs, so benefit little from the super steep STA. Get a bike with a realistic amount of travel for your terrain, modestly steep STAs, and some real rubber, adn all will be good with the world.
  • + 3
 @clink83: albeit one with damn heavy tires and a bit more travel and bounce. But the front end stays planted up the steepest climbs like an xc bike, which is no small feat considering the stack height. I switch back and forth with my Scalpel frequently, and it doesn’t feel awkward at all despite different saddle positions.
  • + 2
 @MikerJ: exactly. On on end of the geometry spectrum is road bikes, on the other end is DH bikes. Finding something in the middle makes more sense for most riders then riding a bike winch and plummet...excuse me enduro bike.
  • + 4
 @watchmen: it's time for the newest evolution of this trope: climbs like an e-bike!
  • - 1
 @davidsamuelhu: The steep seat tube angles don't have anything to do with seat height which is where the knee issues are likely to come from unless you never stretch. Riding a bunch without stretching the ITB can cause some patellofemoral pain. Knee extension should be closer to about 15 - 20 degrees from full extension for optimum power with most people (160 - 165 degrees of extension). Knee relative to spindle doesn't really matter much for that situation (knee pain).
  • + 3
 @clink83: New bikes with steep seat tube angles are absolutely changing the relationship between the saddle and the BB. That is very much the whole point of this geometry change- to move the rider farther forward. "Traditional" geo puts too much weight on the rear and the wheelbases are too short. The steeper the terrain you ride the steeper the seat tube angle is the trend that you'll see.
  • - 1
 @WheelNut: "traditional" geometry is more than adequite, if you look pro XC riders are riding stuff most pinkbike riders couldn't ride on long travel bikes. Steep seat tubes are just a bandaid to make bikes with DH geometry pedal acceptably. A 130m/140mm bike with more balanced geometry would be much faster on normal trails than something like that Pole, if someone bought bikes for the trails they really ride vs the trails they think they ride.
  • + 0
 @davidsamuelhu: I'll buy the conspiracy theory....
  • + 2
 The kneecap over pedal spindle is exactly as relevant as the squat advice that knee shouldn't go beyond toes. Otherwise your knees explode. Both are complete bollocks. Do a little googling if you don't believe.
  • + 0
 @hirvi: yet the mountainbikers who get paid to go uphill fast have their bikes set up precisely like that, while endurobros on pinkbike who think their long travel bikes "climb like an XC bike" say it's wrong. You can guess who I'm going to say is right.
  • + 1
 @clink83: Can you provide some references to indicate this is how the mountainbikers who get paid to go uphill fast set up their bikes? My understanding is the KOPS method is not a prevalent fit technique among pros. If that is incorrect, I would be happy to change my opinion.
  • + 2
 I know people have already spoken on this, but why is KOPS likely to decrease stress on the knee. The only force available to injure ones knee by being outside of KOPS in either direction is gravity, and how will gravity hurt my knee. The only problem I have have ever experienced from being forward on a mtb is more pressure on my hands in the flats and needing to adjust and figure out my hip rotation. I have a knee with a few surgeries under it's belt and it had no clue I was sitting forward of KOPS.
  • + 2
 @Chris97a: It's not about gravity, it's about how the range of motion of the joints and the stress in tendons. By purely coincidental relationship, if the knee was ahead of the pedal spindle at the horizontal forward position, there could be elevated stress on the front of the knee - and vice versa.

Imagine, for example, that you kept your saddle and bar in their current positions, but your BB was moved somewhere ridiculous, like the bottom of your head tube. There would be a lot of strain on your lower back and hamstrings as they stretch just to reach the pedals, let alone apply power. You can see how the relative positions of your hips and feet could lead to stress and injury.

It was by coincidence that, in a particular era of road riding, the typical position of riders produced lowest stress on the knee when their knees were roughly over the pedal spindle at the horizontal forward position. Unfortunately, this coincidence was misinterpreted as a causal relationship.
  • + 4
 @clink83: yeah, but xc isn’t just about being fast on steep climbs. There is also a fair amount of time on flatter terrain at 20 mph where aerodynamics play a part. The upright position with a tall stack height on a long travel bike just robs you of watts at those speeds. When you average over 15mph, aerodynamics aren’t trivial. A lower front end works fine with more traditional SA as you are balanced back off the hands. If you throw a 76-78 SA with a low front end, your hands would have too much weight on them and your quads would get overworked. It’s all about the balance. But on the steep climbs, the xc and road pros slide forward on the seat (on the rivet) effectively increasing SA to keep the front end down. There is some variability in xc pro position, Shurter prefers a slammed low front end while someone like Fumic is more upright.

The other trend that I think goes with steep SA is the more rearward cleat position or flats that many people on longer travel bikes prefer, effectively shifting the steep SA closer to KOPS.

On the other end of the spectrum on a road bike with a slammed 130-140 stem, many pros ride with a seat slammed fairly back and it climbs fine, but are comfortable in the drops for hours. Phinney has this setup.
  • + 3
 2002 called and wants their KOPS back...
  • + 1
 @R-M-R:
What is providing the additional stress into the knee.

Moving forward on the bike changes levels of force on other parts of your body like your back and arms. It also changes your hip angle. If you make this one change but left every other part of your bike for the same you will likely have some problems, but not with your knees.
  • + 1
 @Chris97a: That's getting outside my area of expertise. I just know it happens, not as much *how* it happens. To give it my best shot, though, I've experienced a little of it myself when my hips were too flexed (hips too far behind the BB, though that's using dangerously KOPS-like language to describe it!). My hamstrings weren't flexible enough for that position and other muscles had to pick up the slack. Developed tendonitis at the inner head of the gastrocnemius, which I understand to be not uncommon, along with irritation of the hamstring.

Similarly, a very open hip position (hips forward, relative to BB) can reduce recruitment of the hamstrings and glutes, putting more demand on the quads. Patellar tendon issues are the common result.
  • + 3
 @tlilly: I used to do professional bike fits. It's 100% BS. We measured the customer and put the measurements into some fancy looking formulas, but the formulas also had 4 or 5 completely subjective parameters which would allow you to get any fit you wanted, and then the customer would ride the fit on a trainer and we'd adjust until they felt comfortable, which made it even more subjective. In the end setting proper seat height and cleat position is important to not wreck your knees and everything else is 100% subjective depending on what feels comfortable to you, as long as your body doesn't have any weird asymmetries. If you're a road racer, aero position can be important too, but outside of that it all boils down to what's comfortable for you. Rich people ate that shit up though, so easy to sell a $250 bike fit to the casual Saturday coffee and scone ride crew as if it's going to make a difference on their 14mph avg speed road ride.
  • + 2
 @andrewfif: Can I get these articles from you? I'm a physical therapy student with a keen interest in bike fits!
  • + 1
 @dthomp325: couldn’t agree with you more. I used to do bike fits back in the 90s at a shop. All sorts of formulas and I lived with a tape measure around my neck at the shop like a tailor. I look back at think how much of it was bullshit.
I got really into Hogg’s fit technique and what he was saying years later which blew out all the old formulas. For awhile after that, I was helping fit my teammates or friends loosely based on our understanding of his theories. Most people were set up with KOPS and then we worked from there for the changes, sometimes not much change but others were pretty significant. I think just about everyone was happier and ended up with far less hand numbing or back pain, and after about 30-60 days with the new fit, most showed more power. My changes let me complete a couple Hundos on the mtb and some really long days backpacking without hand or back pain, something I always suffered with the old fit charts.

I remember reading Lemond’s description about Italians back in the day setting cleat position, pretty much slammed the cleats all the way back and called it good. Funny how we are almost back to that.
  • + 2
 @dthomp325: Same here. Worked for a couple shops and even a custom builder. A 7'1" client broke our formula and we built a bike so large he couldn't even get on it - might've fit someone well over 8' tall ... maybe.

Similarly, a mountain biking friend of mine paid a triathlon shop over $200 for a fitting that mostly considered his hip angle; with a mountain bike height front end, they sourced a seatpost with several inches of layback to give him a triathlete's hip angle.

I'm not saying all fit formulae are nonsense built from coincidental relationships that only work for people in the middle of the bell curve ... just most of them!
  • + 5
 There is so much great speculation, but so little evidence. There simply isn't any good evidence that a steep or shallow STA has an injury-reduction advantage. I feel more comfortable, and Strava says I climb faster, with a steep STA. Therefore thats my preference.

Its true though, on the flats its not as comfortable. When pulling my kids around in the trailer on neighborhood streets, or when some of my trails require riding on a road for a bit there is more weight on my hands than I would like. HOWEVER, most of my trails (the fun ones anyways) are winch up and drop down. Steep STA shine the best in this type of terrain.

Finally, XC bikes don't need steep STA because they don't sag 3 inches into their travel and spend more time on flats.
  • + 0
 @R-M-R: people rail about kops like it's a set in stone thing, but it's really not. However, you can look at just about any XC racer and they all look pretty much the same...straight back round 45 degree, legs roughly 25-30 degrees, knee aligned over spindle.
  • + 1
 @clink83:
Pro Road cyclists as well. This is because if you are quite fit and riding on more mild terrain, KOPS is a good place to start.

For most of us that is not our reality and so KOPS is just a funny thing that helped people sound more educated when trying to sell road bikes.
  • + 2
 @clink83: KOPS *is* a set-in-stone philosophy, which is why people rail against it. If we take it as a general guideline and tell riders to put their knee more or less over the spindle, then adjust to preference, then we haven't told them anything, since all (upright) bikes will inherently put you in this range.

Yes, pro road and mountain riders mostly use similar positions, but not all. Adam Hansen uses almost a TT position on his road bike, a few riders still slam the seat rearward on offset seatposts, female XC riders often ride super far forward, Jaroslav Kulhavý rides that wacky seat angle ... there's enough variance even within the pro community - never mind the amateur community with our dysfunctional body shapes - that KOPS provides no actionable insight.

As I mentioned before, the best counterexample to KOPS is that recumbent bikes exist and don't inherently cause physiological problems.
  • + 1
 @whambat: well, a lot of pros are riding frame too small for them in an attempt to be aero, which results in the setback saddle....there are lots of stories of teams having fits done on riders and they make more power in a more upright position, but then they go back to the slammed position...

Also if you look at a lot of the xc riders who have a "slammed" position when they are on the bike the saddle to bar drop isn't as big as it looks, they are just tiny guys on 29ers with tall front ends.
  • + 2
 @clink83: I used to be the lead developer for a road bike clothing company, and one of the sponsored racers (who won a USAC national title in womens CX) complained about this. The team mechanic forced her on a small frame (i think it was an Obrea) and had to run a ridiculous 140mm stem. The grizzly old mechanic is the same type of guy who tried to force me into ski boots with a 98mm last (my current boots are 105 and punched out from there!). They have their ideas on what fit should be and to hell with "science" "progression" and "new information". After they switched frame sponsors she up-sized by 4 cm (to a 54cm, I think).
  • + 3
 In the road world, riders are starting to slam their bars lower, slide their seats forward, and tip them down to get more aero. This flies in the face of KOPS, and in this video they claim that legacy road bike riding positions are partly because of UCI restrictions on geometry:

youtu.be/69OzE3KB2IY
  • + 2
 @dthomp325: I also don't give a hoot about fancy formulas, but 100% is harsh. Even if fit were reduced to shoe/insole/orthotic fit and cleat positioning, that percentage could be significantly reduced. Too many knee problems originate lower down.

Another component of fit should be size and model selection. There was less choice when it was a current model, but just looking at the Spark in your profile hurts me. Nowadays a Ryve could be more ethically suggested. It's no wonder there's confusion on Transition as despite the marketing of SBG, their STAs aren't all that slack. Long inseam folks are likely to size down in order to get toptube to fit. 'Get a medium,' as advised above, is popular advice here.
  • + 3
 @clink83: if you read my comments, I say that XC bikes don't need this as much since they spend more time on flat sections than an Enduro bike, plus they don't sag 3 inches into their travel.
  • + 0
 @hamncheez: Well, enduro bikes aren't designed to be fast uphill either, they have steep STA to push the rider forward so they can survive the uphill climbs. I dont know why people have such a hard time understanding that gravity geometry sucks for trail and XC riding where you actually care about going uphill. If I said my XC bike descended like an enduro bike people would laugh me off this site, but you have yahoos on here saying DH geometry bikes climb like an XC bike and that fit doesnt matter, which is equally stupid.
  • + 2
 @clink83: You’re right, Nino’s position isn’t extreme, for a roadie. But there are very few that are more slammed on a mountain bike. It works for him, he’s developed the neuromuscular adaptations for that exact fit his whole life and messing with it would throw his whole game off. And he has developed amazing skills of being able to ride that setup like no one else can. The man is a Jedi.
But I’d hardly call that the fit I want to emulate for a trail bike for me. I spent too much time on a slammed position on a road bike and now like a decently upright position.
When some of us say climb like an xc bike, it’s basically referring back to when you had to fight to keep the front wheel tracking even on a 140mm bike and it straight up sucked. Instead we had Talas forks so we could drop the travel, effectively giving a steeper SA for the climb, but it would suck if you forgot to flip it back. So when you can ride a 160 travel 29er, don’t have to change the travel, and barely have to weight the bars to climb a steep pitch and keep the front end down, like an xc bike, that’s what we mean. Not that it’s as efficient, light, or as fast as an xc bike, but not struggling like a trail bike. I have no trouble riding my 76SA 160mm bike in 6,000 vert days. I wouldn’t have said that just a few years ago with the older geometry.
  • + 0
 @whambat: dude look at the rider behind him. Almost ever WC xc rider has the same riding position. You guys just spend too much time looking at bike checks thinking they have extreme setups without watching them ride. Most of them have the standard KOPS fit that you guys say is outdated. You can talk all you want, but I have raced enough XC to know you guys are clueless and would get dropped by 50 year old cat 2 riders (who drop me too).
  • + 1
 @davidsamuelhu: I agree, it seems a lot of new bikes are great at descending and great at steep climbing, almost all reviews just talk about descending and climbing. Rarely is there mention of how the bike feels for the majority of a lot of people's rides, the flat land between the descents and steeps. I bought a Commencal Meta AM V4 off the back of reviews and it was great down hill and fine of steep climbs but it was a horrid cramped un natural thing to sit down on and ride on flat trails.
  • + 2
 @clink83: because XC bikes and road bikes don't squat on steep climbs and thus don't get slacker on the climbs.

Steep seat tube angles are here because of the squat. That 75° seat tube angle that is marketed turns out to an actual angle of closer to 70° (relative to the ground) once you sit on the bike and then start climbing.

Plus, short chainstays and big wheels and tyres are the reason for bent/offset seat tubes, not the reason for steep angles. Steep angles actually enable short chainstays because you move forwards with it and are not impacted by the short rear as much as you would be on a slacker bike.
  • + 1
 @Bob12051968: top tube lenghts have stayed much the same, but steep seat tube angles have increased the reach numbers at the same cockpit length. And that is why reach is such a useless measurement (like Mike already wrote in the article).
  • + 1
 @clink83: No, the steep seat tube angle moves the rider forwards over the BB. The long front centre is needed to have a proper cockpit position with the steep seat tube angle, that is all the compensation to it.
  • + 1
 @R-M-R: That knee bursting into flames is the exact analogy i've used before (though mine was exploding, i think).
  • + 1
 @MikerJ: i'd limit the steep seat tube angles based on frame size, not on suspension travel i think. The actually steep seat tube angles are great for tall riders, sitting way above the stack height (where the difference in the two angles is most pronounced).

I'm kind of thinking smaller riders could actually maybe use a slacker seat tube angle (when the rear wheel would fit under the seat and everything).
  • + 1
 @clink83: the guy behind him looks to have at least 10 degrees more upright on the torso. Did you look at his bike setup?: -25 stem, seat pretty far back to compensate, but in interviews he talks about liking a lot of weight on his hands, so he probably doesn’t need his seat far back with an offset post.

Yes, plenty of xc pros are close in fit, but Nino being on the far end of the crouched spectrum these days.

No, I can’t keep up with Cat 2 these days. At least not on the climbs: I’ve gotten too big in the gym for my firefighting job, and my diet is not as disciplined as it once was. But over 50 Cat 2s are a lot of my riding partners, so are some former Cat 1s. I’ve spent plenty of time in Lycra with a number plate on my bars or on my back between 1990-2013 in xc, road, and cx. Never liked road racing much though. I gave up on racing in 2014 when training to break 9hrs on a hundo with 14k of vert in Colorado when I dislocated my shoulder (missed the 9hr mark the year before by 30 min from dehydration).
But my experience has no relevance to my point that steep SAs are the shit for making long travel bikes climb worthy and my Ripmo is the bike I grab for long days of up and down. I have to move up on the saddle nose less on my Ripmo than I do my Scalpel on steep climbs, it really does climb that well, and combined with the long reach I am not too upright or cramped, just have to get used to a long wheelbase. The Minons I have on the big bike slow it down more than the travel or angles on the climbs.
  • + 3
 @Primoz: Reach is not a irrelevant number. It is irrelevant to how large the cockpit area is while seated but is the only length that matters when you are descending and not seated.
  • + 0
 @Chris97a: I have said this quite a few times and will say quite a few more.

On any bike that you pedal seated fit is THE MOST important part. Descending doesn't matter. It takes you an hour of pedalling on flats and up the hill to do 15 minutes of descending. The energy and time consumption ratio simply makes pedalling fit the absolute priority.

Reach is useful for park and DH bikes and the pumptrack, DJ, etc. bikes. Enduro bikes do not fit here, neither do trail, XC, etc. bikes.

And this article beautifully shows why and how reach is a useless number. I increased the reach of my bike by 6 cm, but the cockpit lengthened only by 3 cm. And the overall fit of the bike increased dramatically through a steeper seat tube angle.

The descending performance? The wheelbase is 7,5 cm longer, it's a 29er and many said it's too long. It goes down the hill like an insane badger compared to the previous bike. I'm riding on a whole new level and it was a night/day change from the old one. Granted, a large factor of it is a 170 mm dropper compared to the 125 mm of the old, but still, the grip, composure and stability this bike has is insane. And it has an 'insanely long reach number' (522 mm in XL). Yet, again, it _WORKS_.
  • + 1
 @Primoz: steep seat tube angles are there to move the seat forward on long low slack bikes, not because of sag. LLS geometry is to go fast downhill, but if you want to go uphill you have to move the seat forward or you will surely up climbs because your COM will be too far back. In reality it's the front center:rear center ratio that determines what seat tube angle you need, the bigger the ratio the steeper the STA needs to be to climb.
  • + 3
 @clink83: When climbing, your weight shifts back, causing the rear to sag more, the front to sag less, and the seat tube angle to slacken. So yes, we do need steeper seat tube angles on bikes with more suspension to compensate for the greater extent to which this happens.

Instead of thinking of the FC:RC ratio, think of the ratio of wheelbase behind the centre of mass to wheelbase ahead of the centre of mass. That becomes a dynamic ratio when sag and ground slope aren't constant, and it's the relevant ratio.
  • + 0
 @R-M-R: that happens on short travel bikes too. If you flipped the lockout switch on your rear shock on an XC bike and something like the Pole in the article so your bike didn't drop into its travel at all, the LLS bike would have still have your COM way further back than the XC bike if the seat angle was the same. Short chain stays and a long front center sucks for climbing, regardless of where in the travel you are.
  • + 1
 @clink83: Having the BB in the middle of the wheelbase or right up the tyre won't change the centre of mass much, if your seat is positioned the same in regards to the rear axle in both cases. But the middle of wheelbase BB, which in effect you are claiming will be better, will be horrible to pedal up, since you will have to push forwards instead of down. I'll take the other option, gladly.

This is your short chainstays, long front sucks situation, which i say is wrong. It's the centre of mass position that's important and that has NOTHING to do with chainstay/front centre length. At least not directly.
  • + 2
 @Primoz:
Your statement completely depends on where you ride. The only time I have felt awkward on a steep seat angle bike is while pedaling the mile or two to my local trails, on paved and gravel roads. Now I have not been on any of the extreme seat angle bikes but once on the trail having the steep SA for the silly steep grinds up is great. Then having that long reach so that my 6'4" self isn't having to do the tiniest adjustments to change the weight on the front v the rear wheel has felt great. It is as if bikes fit me for the first time since I started riding mountain bikes 29 years ago.
  • + 1
 @Chris97a: im not sure it does depend. I sm in the same boat as you and I don't really mind pedaling on the flats, I find it okay even with the a steeper seat tube. I still prefer driving my legs down instead of forwards which is the main benefit of steep seat tubes.
  • + 1
 @clink83: It happens on road bikes, too, because the rear tire sags a millimeter more. It's just a matter of the extent to which it happens, and the extent is a lot greater with more travel.
  • - 1
 @Primoz: if you look at XC bikes they most certainly do have longer chain stays and shorter front center, which is why they have slacker seat tube angles, which is why if you set them up in that outdated KOPS fit they will blow any of these long travel bikes that people claim "climb like an XC bike" out of the water on climbs.
  • + 1
 @clink83: Scott's Scale RC has 425 mm chainstays. Trek's ProCaliber has 435 mm. BMC's Teamelite has 429 mm. My Bird AM9 has 440 mm chainstays. I don't know what wolrd you live in, but in mine, 440 is more than 425, 429 or 435 mm.

You can find an XC hardtail with more than 440 mm of chainstays, but then i will find an enduro bike with an even longer chainstay. It's simple, hardtails don't have suspension and can have shorter chainstays, if needed.

Of course they have shorter fornt centres, since they don't have as steep seat tube angles, the reach doesn't need to be as big. And since they don't have the head tube angles as slack and forks as long, the front axle is much closer to the BB. Therefore shorter front centre.

And, like said many times here, where is the magical KOPS on a recumbent bike?
  • + 3
 @clink83:
XC bikes climb well... Period. Not due to KOPS.
  • + 0
 @Primoz: every single XC pro I've seen has their bike seat up with their knee dead center over the spindle, which goes against everything the posters above said. Most mountain bikers I see have their seats too low and their bars too high, no wonder they think they need a steep sta to climb. Fit does matter.

I have a scale RC, but the front center isn't long because of the seat tube angle, it's because you don't want the front end pushed out on climbs. The scale still is long and slack for an XC bike, in order to run the cockpit on my old hardtail I have now I would need a 100mm stem instead of an 80mm, and it has a 68* hta. It doesn't climb as well as the old bike though...
  • + 0
 Here's a good video by Vorgsprung saying the same thing, what do they know?
youtu.be/P18SutYYL5I
  • + 4
 @clink83: A lower bar and higher seat would close off your hip joint even more. Having it opened up on my new (steep) bike i can only say i like it very much.

As for the pros and knees over spindle... Everybody riding a bike pedals, surely you can't move around on a bike without pedalling!!! *Cue chainless downhill races*

Please, please try and use your head, what would happen if you would rotate the biker, seat, BB and handlebars by 90°? Where is your KOPS now? What about in space? They pedal bikes there. In space it can be PSOK!!!

How many times must it be said that KOPS is a happy coincidence and that there is simply no logic in it having any merit? Why would you have to have your knee over the spindle? How will you have your knee over the spindle on a recumbent? On a cruiser? What if you laid on your belly and had the pedals behind you?

Please tell me why would the knee have to be exactly over the spindle? What is the magical force, field or any physical property that requires that??
  • + 2
 @whambat: The balance point changes when you're going up hill. Steep seattubes are essentially bike fit optimized for climbing, with the assumption that the seat will be out of the way for descending so that doesn't matter. It would be a suboptimal position for level terrain, just as a bike fit optimized for flat terrain is suboptimal for climbing, hence why you end up scooting forward on the seat to compensate.
  • - 1
 @R-M-R: It's for efficiency. You get the most help from gravity when you're pushing straight down on the pedal at the max of the power stroke. Recumbent bikes give up mechanical efficiency for aerodynamics and comfort.
  • + 2
 @TucsonDon:
Incorrect.

A person's position on the bike is optimized by balancing the forces on the contact points for the terrain that they most often ride.

The force of gravity on someone's leg helping them pedal is not a consideration.
  • + 2
 @TucsonDon: The weight of a thigh is ~10 % of the body weiht for the average person, the lower leg (below knee) is ~6 % including the foot. So your whole leg, where the whole weight is not helping the pedal stroke, weighs ~16 kg for a 100 kg dude. That same leg can generate multiples of the force of the weight of the leg in muscle power by actually pressing on the pedals.

Plus, the heavier the foot, the more it presses onto the pedal when it's moving upwards. So it cancels itself out. So your efficiency is... none.
  • + 17
 Does anyone else just scoot their taint all the way forward on the nose of the saddle for steep techy climbs? It don’t feel great but it gets the job done.
  • + 10
 used to until i started riding steeper seat angles. being able to climb steep tech in a comfy centered position has been a blessing to my taint well being.
  • + 4
 I thought this was the norm, just shove the seat up your butt and get er done.
  • + 31
 Pressure on the prostate helps you climb max.
  • + 3
 @xy9ine: Exactly! Longer travel rear suspension arrived first and would, as rear suspension does, sag deep into the travel on climbs. We're only now compensating with steeper seat tube angles, which also require longer reach. I've had to flip seatposts into the forward offset position to deal with this in the bad old days. Modern geometry is wonderful, but everything had to evolve in unison; the stepwise changes (ex. suspension travel) moved rider biomechanics in the the wrong direction for many years.
  • + 4
 I had to all the time on my old bike (Pivot Mach 6 v1), but with my current ride (Ripmo) not nearly as much. The steeper STA was one of the reasons I got a new bike. The Mach 6 is great, but with a 72.3 degree STA it takes hardly any grade at all before you have to move forward to keep the front end down (and you're also scrunched for room because of the relatively short reach). With the Ripmo (76 degree STA) I don't move forward until the climb is very steep indeed, and it never feels cramped.
  • + 4
 Did that for three years on my ‘14 Remedy and hated every minute of it. Since switching to a Sight, that issue is history. Was never able to get my hips in the right place on the trek. Always felt behind the bike on climbs. No amount of switching angles, saddles or stems could remedy (haha) the issue. My norco has a goldilocks seat tube angle for me.
  • + 15
 In my opinion seat angle matters more for climbing than suspension linkage design. On my Turner sultan with sweet DW-Link BUT a 72 degree seat angle (150mm fork, offset bushings) VS my aluminum Sentinel (3lbs heavier) with regular old Horst link and a 76 seat angle I set climbing PRs.
Maybe I was just feeling good those days...but as far as climbing feel goes, steep seat angle > DW/VPP/ect.
Now I have both DW-Link and steep seat angle on my Ripmo Smile
  • + 17
 I'll take that outdated Sentinel off your hands, thanks.
  • + 5
 The only thing that matters, in the context of the points you raised, is where your hips end up, relative to the BB. The actual and effective seat tube angles don't matter, nor does the seatpost offset or saddle rail position. It only matters where you end up.

(The suspension kinematics are another matter, of course.)
  • + 3
 This. I can now clean technical climbs and feel much better on sustained climbs on my Evolink 131 than I did on an old-school carbon hardtail with basically roadbike angles. It's something like 10 lbs heavier.
  • + 1
 Unless it is really rocky and/or rooty technical climbs. Then suspension platform makes a difference.
  • + 0
 @tacklingdummy: I'd actually hazzard a guess that less so. A geometry with less antisquat might follow the rocks and roots better and be more forgiving.
  • + 12
 As someone who has long legs for my height (1m86/6'2 , 92cm/36" inseam) I often have a lot of seat post showing. So actual seat angle matters to me . Unfortunately very few manufacturers list them in geometry charts.
  • + 10
 73 degree seat angle is the optimum seattube angle determined from road bikes on flat ground. It took 20 years of MTB production & development before someone asked the simple question "does this make sense" on a MTB that is being pedaled uphill. Answer was no. Lol
  • + 6
 True, and even after we started to question this, it took several more years for people to notice suspension sag throws off the static geometry, especially when climbing!
  • + 1
 We might apply the same stunning level of inquisitiveness to short chainstays.
  • + 1
 @alexsin:
Especially considering chainstays all being the same length on all the sizes is a remenent of steel manufacturers only making one or two sizes of chainstays and you are going to be drafting right so let's tuck those wheels under you as tight as possible.
  • + 1
 @alexsin: I wouldn't be so fast. With a steeper seat tube angle your chainstay can be shorter and the axle to axle balance still be OK.

Plus, any differences in chainstay length need to be an actual difference, not what Norco has done (move the BB shell forwards on larger sizes, making the STA even slacker - counter productive to the MAX).
  • + 7
 This hits home as am just figuring out why a Scout SBG frame I got in M that I expected to fit like a glove feels cramped. The distance from saddle to bars changes a ton at slack angles, and not so much on these new bikes, but this doesn't show up on the geo chart, so how are you supposed to figure it out? I went to the bike shop and had to measure from the stem bolt to seatpost center on a few SC bikes to compare (their geo charts are similar to the transition). This now is the only way I can figure out to judge for myself what I'm used too.
Pedaling the steep angle bike on NOT steep terrain feels wrong, I'm way over the cranks, and can't move the butt back any further, I had to dig out a setback dropper post, which puts me 25mm back to where I'm used to being. I have yet to get a ride in and see how it feels. The industry needs to update the charts and give us ETT at multiple heights, this will clear up the confusion.
  • + 2
 "..but this doesn't show up on the geo chart, so how are you supposed to figure it out?"
Literally all geo charts have ETT (effective top tube) measurement. That's how..
  • + 2
 And as the article mentions, actual seat tube angle gives you a very good idea how much ETT will change when raising the saddle higher than slammed bar position.
  • + 8
 to be fair, I had a pole and now I have a nomad, the nomad fucking sucks for climbing in comparison. so twitchy and light at the front, feels like it always wants to wheelie
  • - 3
 Which is perfect for gnarly climbs with lots of ledge-ups. Love my slack sta climber.
  • + 2
 @JohanG: Interesting....I too question the blanket statement that steeper SA is always better for climbing, in particular tech climbing. Its not bad, I think in general the slight steepening has been a good thing, but I think its a bit much to necessarily hold it out as the be all end all of climbing performance. Steeper SA also moves weight off the back wheel which can potentially reduce rear wheel traction and I myself don't feel as strong as the effort moves from my hips/butt/hams more directly into my quads (as SA gets steeper) . Balance of all parameters as always.
  • + 5
 @PeterT I came off a nomad and now have a Machine, know where you’re coming from.
Guys it’s pretty clear when you ride it, the Pole just climbs better. Everywhere. Tech or not. Even though it’s heavy and long, it’s the #1 pleasant surprise for me about the bike is just how damn well it climbs. The body position is just that much better, and it shows... wouldn’t have believed it until I tried it.
  • + 1
 Went from a 2015 Reign (L) with an actual seat height angle of 72° to an XL Bird AM9 with the same angle of 75° and it climbs techy, steep stuff MUCH better. I'm relaxed on the centre of the seat where i used to pull over the bars and insert the tip of the seat into my ass on the Reign. Plus it's a 29er now so it rolls over the bumps with ease.

Steeps eat tube angle does move weight off the rear, as in not all of it is there. Which is a clear bonus. It's not that there is too little of it, it's that there was too much weight on the rear before.
  • + 6
 There certainly is a point coming where we'll take it too far. Hell, it may already be here. I haven't ridden any of the 78 degree + bikes.

But it's hard to argue against modern geometry. My current bike isn't extreme by any means (Transition Smuggler) but it's squarely in the upright seat angle, long, slow, and slack territory for a 29er with 120mm of rear travel. The damn thing rips down and the climbing position is so comfortable compared to my previous bikes with ~73 degree angles.

I won't go into the whole reduced offset fork thing, but I'm a believer and have been since testing both the Ripmo and the Smuggler at Outerbike.
  • + 5
 Don't these numbers all change once you sit on the bike and sag the suspension?

My understanding is that 30% rear suspension sag is not necessarily 30% rear suspension travel since the leverage ratio changes through the shock stroke. In the front 30% sag is 30% travel. As a result, a 150mm/150mm bike set @ 30% sag front and rear is no longer level like it was when it was sitting there and the angles were measured. Would get even more wonky on bikes with different travels F/R or different sags F/R.

Would it make more sense to give angles at prescribed sag values?
  • + 2
 Yes, and when we're climbing, the rear suspension sags even more and the front rises a little, making things even worse.

The problem would be in agreeing on the sag at which to take these measurements. Even if an industry that can't agree on the saddle height for effective seat tube angle could agree on these sag numbers, what do we do for a highly progressive rear linkage that benefits from more sag or a linear suspension that should be run with less?

I agree with you in principle, but I don't think it can be implemented.
  • + 3
 @R-M-R: I'm not sure what you're talking about. Seems like everything else in the industry is settled. Last I checked we all agreed on bottom bracket type, head tube size, handlebar control configuration and wheel spacing.....
  • + 2
 @NukePNW: I wish that was the case.

What tire size is used for BB heights? When measuring reach, at what stack height is the reach taken (stack and reach are not independent and reach should be measured at a standardized stack). What fork offset is used when measuring wheelbase? How is the effective seat tube angle "effective" when no one actually sits at the height at which it's measured? When companies quote kinematics numbers, like anti-squat, what gear combination, centre of mass height, or point in the travel is being referenced - these things can double or even triple the value! When measuring standover clearance, is it measured at the lowest point or at some arbitrary point along the top tube?

None of these things are standardized, so there's no hope of standardizing the sag at which a seat tube angle is measured - even if there was, at what height would we measure the seatpost extension? And would that height change for each size? What if a bike fits uncommonly long or short, relative to the nominal size, and most riders size down or size up on that model - should we try to incorporate that?

Speaking of which, there is a bike for which the size Small has a reach approximately equal to the median reach for size XL frames - and its front-centre length is in the top 25% of XL frames! Anyone who shops for bikes based on a familiar nominal size could be in for quite the lesson on standardization.
  • + 1
 @R-M-R: Which bike is this? Pole's Stamina?
  • + 1
 @Primoz: One of the Nicolai models. On mobile and don't feel like accessing my database, so can't be more precise now! I equated their "Long" size to Small, since they have a five size range and that's the smallest.
  • + 1
 @R-M-R: The base 'Long' is in fact, effectively, a small. Could have been a Ion G15 or G16, otherwise the current one is simply a Nicolai G1.
  • + 1
 @Primoz: Yes, that's why I equated "Long" to small in my database.

Now that I'm at home and can look at the database, the G16 has a front-centre of 833 mm and the Machine 160 is 830 in their versions of size Small. That's longer than 80% of XL frames in the past six years.
  • + 4
 Steeper seat angles have caused me bad back pain and knee pain. I actually have to take a break from my two newer bikes and ride my older bikes with STA around 72.5 to let my body recover. I'm definitely not sold on this steep STA thing.
  • + 8
 Pick a seat tube angle and be a d!ck about it.
  • + 9
 No water bottle.
  • + 4
 I have a Pole Evolink 131 in size medium. When I first built it up I put the seat way forward and slightly angled down, and the shortest Renthal stem I could get (35mm or something.) All of which was the recommended way to set up the cockpit, and guess what? Waaaaaaaay too short for seated pedaling (and having the stem that short made the handling feel weird being behind the steering axis.)

Pushed my seat waaay back, threw on a 60mm stem and boom- now it felt natural and fast when seated.

Another quirk of steep seat angles: dropper length is even more important. With the seat being so central on the bike when you stand up you're above the seat, but it's no longer behind you (like it would be on a bike with a slack ST angle.) Which basically means you're using the dropper more than (at least I was) used to in moderate terrain just to have the seat out of the way a reasonable amount.
  • + 1
 How tall are you? Did you get the recommended size by their charts or downsize cause you know better?
No offense, just a question based on curiosity.
  • + 2
 @hirvi: seems a downsizing was at play here, can't be anything else with a comment like that...
  • + 3
 After test riding bikes with 76 and 77 degree seat angles (Ripmo & Offering) I’m sold. So much better climbing then bikes slacker SA’s only a few years old. Zero front wheel lift on steeper tech climbs. Plus no need to slam the seat forward with nose down or shift weight constantly. Anything that saves energy going up is a good thing. All bikes moving forward should be within the 76-78 SA range.
  • + 3
 Jesus f*ckin Christ. Too much money they have. Too little weekends to fight.

Why is this is still a subject. It was all drilled 1000 times. Suuuper long bike are for pros that need speed and for cripples that need stability. For everybody else we have normal bikes. Now. For those super long bikes you NEED super steep seat angles because otherwise they are unrideable (like this whole Pole shenanigans). So there you have it. You're normal bike park rat: 75-76 for you. You're super duper fast or you're super duper weekend woriorish: straight angle and up goes for you Big Grin .
  • + 1
 A super long bike made me much more comfortable and ride much better and faster. Maybe i was a cripple. Doubt it though. Also, a super steep angle is actually the thing that makes a bike super long, because you need a long reach to have a normal cockpit length. You're missing the reason for long bikes. For bike park rats the angle actually does not matter at all since you're not pedalling anyway. So it can be much slacker than that.
  • + 3
 Didn't address the power you make from different seat angles and positions. Steep seat angle means you're gonna be upright and pedal from your quads. Getting seat back recruits the hams and glutes which is Paramount. Scooting up on seat is incorrect technique. The correct tech is to scoot ass back and drop chest over bars. But the trend these days is to ride on your toes and front load with quads and pressure on hands. So not surprised people don't take this into consideration. It's always change the bike not refine your technique. Problem is the industry does not know the correct technique and have been mislead by sport level coaches that don't know how to ride right. And or Pros that can't tell you what they're doing so they just regurgitate the trends which are set by said sport level coaches
  • + 3
 Why was this downvoted?
It's probably the most important question here.
Steep SA is good for some things, power efficency is not one of them.
  • + 3
 @nozes: I always get down voted. People don't like the truth. Everyone wants the short cut and excuse to spend more money. When I used to road race (motorcycle racetrack) people would spend all the money on engine mods, latest model, geometry adjust. Fancy suspension, etc. All it would do is make them that much faster on the straight away or that much closer to a yard sale. Never did it give them faster corner speed or better technique....unless they were in the small percentage of people who were very experienced and or talented.

I find all of mountain biking to be about the equipment or get fast tricks n tips. Nobody wants to hear that the latest n greatest isn't needed and that their technique sucks and everything they thought they knew was wrong.

In my opinion, mtb went down hill when all the engineering geeks with expensive degrees thought it would be cool to work in mtb industry and try and make real money turning a grassroot hobby more mainstream. All about the money now they have to constantly keep sales increasing exponentially. So the machine works hard to keep people thinking they need more and new and go faster, spend, spend, spend.
  • + 2
 @nozes: but back to seat tube angle. With the long travel mega slack bikes when pointed uphill the frontend does not sag which puts all the weight on the rear of bike so you do need a steeper SA than in prior years. But there's a limit. And the farther you push past that limit the worse it gets as the trail flattens out. So trail bikes with 65 HA and 78SA are stupid. But if you truly ride in steep up and steep down terrain constantly, a bit steeper than a few years back slack SA angles.
  • + 3
 Steep actual seat tube angles allow dropper posts to work smoother with less bushing stance which can help reduce overall length of a post. It also allows for a post to be lighter because you don't have to leave as much material in it to offset deflection in the post.
  • + 2
 True, but even if the seat tube/post were vertical, the post would still have to carry bending forces unless you ride only on flat ground. As soon as you point the bike uphill (and this is the scenario where you're most likely to be seated), that post is working as beam as much as it is a post, and that's really not impacted that much by steeper STA.
  • + 4
 @ReddyKilowatt: for any given pitch, the steeper the STA, the more vertical the dropper post, and the less lateral stress on the bushings.
  • + 2
 @hamncheez: Sure. And my point is that it isn't a huge change. On a 10% climb, changing STA from 74 deg to 76 deg only reduces the bending load by about 10%. I guess we could argue whether that's significant. My claim is that it's really not.
  • + 0
 @ReddyKilowatt: deflection in seat posts is what has kept some of the big names out of the 200 mm ring. All they need is a small reduction in the forces causing the deflection and maybe you will get a 200 mm reverb or transfer. At no point did I mention climbing benefits but even the placebo effect of a steep seat tube is enough to get you climbing strong
  • + 3
 @myotherrideisyourmom: I'm down! I have long legs and like the steeper STA direction. I'm not trying to claim there aren't benefits.
  • + 3
 Thanks for shedding some light on this aspect of bike geometry. Being a taller rider the STA can make a large difference in climbing steeper terrain comfortably, shorter riders aren't as affected by this due to the shorter seat tube and rear center to front center ratio generally being more favorable.
  • + 1
 Yes, this...I finally had this revelation last year. I guess the steep effective seat tube angle mantra found me. I have a 35" inseam, so with my saddle at the correct height my back end is way over the rear wheel with a slackish seat angle. I now have a bike with a 76 degree seat angle and the bike climbs like incredibly. The other thing is now I can climb steep ledgy sections that I've not been able to clean before. Another thing about my new bike is the front end is light and poppy with short chain stays, but the front end still tracks the ground on steep climbs. I understand that this all weight distribution, but its interesting that its taken years to get mountain bike geometry to where it needed to be.
  • + 2
 On an ENDURO bike climbing is where all suffers, so a forwarded saddle is good, and when the things turns down, you push the saddle and keeps forwarded, meaning clearance... The Commencal is good but the Pole is better.
On a TRAIL you need a better pedalling position, so a little back saddle is good... That's where the Commemcal is better than the Pole.
Perfect for me? A little bit longer saddle, and forwarded, where can I keep traction on climbs and good pedalling on roads to the trails... That is not a problem of angles.
  • + 2
 Some good info in this one.

I've ran my own bike with eSTA of 75, 75.6 & 76 degrees (measured at actual seat height changed by using anglesets, seat position, and stems) and I feel a bit stronger at 75.6 degrees and I do lots of steep climbing.

I just purchased a new bike for my wife and she climbs less steep things than I do and as a result I purposely choose to stay in that 75 degree range. However I wouldn't put myself or her on a 72-73 eSTA ever again and in fact that and other desired geo changes are what led me to get her a new bike. The silly short reach and ETT dimensions on bikes from just a couple of years ago is actually a MUCH bigger issue than the STA.

And a forward offset dropper post would only work if your old bike, was 2 sizes too large for you. And then the seat tube length is problematic.
  • + 2
 Not new, it's just finally being addressed! This issue is magnified for tall riders. So frustrating to raise a seat for climbing but to have the seat also go back so that you're falling off the back of the bike with weight so rearward.. then slam the post down and it goes forward totally in the way of the knees. Those angles are completely backward for how I want to climb steeps for two hours and rip descents for 15 mins So, no man, I've been pissed about this for years. But now with enduro, bikes are finally being made for how some people ride. No more lugging dh components around on trail bikes. And instead of designing bikes to climb lame trails now we're talking about real climbing, for which combining slack seat angles and long travel sucks, straight up it is now let's roll
  • + 7
 so 90 is next, right?
  • + 5
 Why even bother? Let's do 95! Wink
  • - 3
 Exactly! I don't sit when I ride except for when I'm chilling, so I keep my saddle low. The height I have it in my pictures was just because I needed some length to clamp it in my workstand during assembly. I leave it about 5cm lower than that for riding. But I feel for a low saddle, a relatively slack seat tube angle would be ideal. I get that people who climb seated would prefer a steep seat tube angle though. To appeal to both, ideally the seat tube is really steep (90degrees as you propose sounds nice) with a seatpost with a lot of setback. That would give you the steep effective seattube for the high seated XC climbs and the slack effective seattube with the low saddle. Another advantage is that they no longer have to have a kink in the seattube to clear the big rear wheel people are running these days. Which in turn would allow people to run longer dropper seatposts with more travel. The amount of exposed seatpost I'd have if I'd raise my saddle up to XC height would be 300mm. Yet I usually ride with my seat slammed. No dropper seatpost currently has this amount of travel. With long straight seattubes, this would be easier to realize.

Of course there are downsides. The huge setback requires a larger diameter seatpost (or dropper seatpost stanchion) which in turn requires a larger diameter seattube to keep up. Plus of course there needs to be enough room for the rear suspension (shock, linkage, wheel travel etc). It is a bit of a chicken-egg dilemma and I expect a company like Specialized or Liteville that does both dropper seatposts and frames have the edge here as they can develop them as a system. Though of course it probably doesn't take much for a company like Cannondale to do that too. That would be the first square seatpost with roller bearings.

Either way, it may take a few years but eventually things are going to happen exactly the way I told you here.

Now, who wants to borrow this crystal ball next?
  • + 7
 @vinay: Asking for a friend. Are you sure it's not Crystal meth?
  • + 2
 @watchmen: Technically, I'm on the mirror image thereof. Still amphetamin indeed.
  • + 2
 @vinay: That explains it.I'll let them know.Thanks
  • + 1
 @vinay: I feel, I hardly ever sit when I'm on my bike when I ride, on the pedals 90% of the time lol it's way more fun to ride that way
  • + 1
 @vikb: well 95 would bring the saddle forward for climbing and back for descents. Sounds perfect to me. Just pair it with a rearward axle path for wheel clearance from the odd shaped tubes and we're rockin
  • + 2
 @coolj43: Yeah man, the bike really comes to life like that. Riding my bike seated feels like wasting my time. I'm on my bike and it isn't even fun. I sure must be doing it wrong then!
  • + 6
 please everybody just go and ride your bike
  • + 15
 We will, and we'll enjoy it more because our bikes fit better than ever, thanks to the people who are willing to think about geometry and biomechanics, rather than telling people to stop talking and go ride.
  • + 2
 I have just moved from an Evil Following with a very slack seat tube angle to a Geometron G15 with a steep seat angle, the difference is night & day, the Geometron places you over the BB for a way more natural/efficient/comfortable climbing position, the Evil felt like you were pushing from behind the BB even with the seat slammed forwards, the Evil was a chore to climb suffice to say painful at times, even though the Geometron is heavier & with more extreme geometry it is a far superior bike to climb & ride longer distances on, I know there are other geometry factors to consider, but there is a reason why road bikes have settled on certain ST angles & this also translates to MTB. I think slack ST angles in MTB were born out of aesthetic to have design symmetry between HT & ST angles, when you first see a Pole or Geometron the HT & ST angles look wonky, but the old phrase rings true 'form follows function'
  • + 2
 The pushing from behind is the exact feeling i have on slacker seat tubes. And has been removed with a steeper bike.
  • + 2
 Strange that noone mentions knee position... didn't inspect numbers but judging from the picture and imagining myself sitting on Whyte and then on Pole, I'd say on Pole my knee would not be at 90 degrees as it should when the pedals is at "3 o'clock" position which could reduce pedal effectivness and even bring stress to the knee. That is the first seat adjustment I make when I am on the new bike, relative to the BB position.

Maybe I am mistaken but I don't see Pole having BB in a different position than Whyte, while seat (angle) is slammed forward for better pedaling, but is it really better? Because, in a world where machines are pedalfriendly enough for this type of riding they are intended for, I'd rather save knees.
  • + 1
 Why should it be at 90° at 3 o'clock position? The leg is completely extended at 3 o clock position on a recumbent bike...
  • + 2
 Steep STA will raise the saddle further from the ground and shorten the ETT. Having the saddle way jacked up above the grips, and an ETT that is too short, leads to excessive weight on the hands while seated. I prefer grips to be higher than saddle with a short ETT, and grips to be relatively low with a long ETT--I suppose I prefer my arms to be around 90d, relative to my torso.

That and the saddle interfering with out-of-the-saddle pedaling, if not dropped, is annoying. That all said, it feels great on climbs and I got so used to it after a month that I greatly prefer it. That and I think it helps train the same muscles I use for out-of-the-saddle pedaling. Makes me feel like bikes still have slack STA primarily since people want to transfer their seated road bike training over to the dirt.

I know, since I got a near 90d effective STA on my bike: www.pinkbike.com/photo/17190421
  • + 1
 @Primoz: I tried adding a riser stem to my bike, but it felt like I was less connected to the ground having the grips further away from the front axle.

I switched back to a 27.5 Jekyll Med, from my experimental bike, for a ride today and it literally was 15% slower on the road, and harder on my knees on the dirt. Nice thing was that its 420 CS and 1190 WB made its handling out-of-the saddle impeccable, for doing freeride and slopestyle stuff, and had great grip for hammering out-of-the-saddle up steep climbs as a bonus. The shitty part was that the fork/shock sag varied so much, between my seated to standing position.

Makes me wonder how the Jekyll would be with a steeper STA, much longer reach, and steeper HA, but the same CS and maybe a very slightly shorter WB, would handle. Swap out the front with a 29er too. Would get the front end higher to counter the steep STA, and there'd be less weight distro variation between seated and standing. I'm sold on the smoother ride quality of steel though...
  • + 1
 Because the plate set on your cassette is not enough with your 28T front chainring and comlaining about stuff is just awesome. I'm over here freeriding the local trails on a 26 Player in S with a FOX 36 lowered to 120mm, one brake and just pedal as far as my legs take me with the single speed set up. I have 3km steep hills to climb after every ride and just love the leg pump afterwards. Nowadays I am just happy to be outside riding and not meet trail dudes actually complaining about angles and tires. Sheesh!
  • + 2
 And doesn't sag make a difference? When seated on your bike, does sag not change the effective angle.... and so longer travel bikes lose more seat angle at sag than shorter travel bikes, correct?
  • - 1
 Hopefully both your fork and shock are sagging similar amounts, and the STA impact of sag is negligible.
  • + 2
 Yeah , totally agree islandforlife. @ReddyKilowatt: nah they don’t sag similar amounts at all. Even ignoring the fact that most riders would set their rear with 25-30% and forks 15-20% sag on the flat, once you point steeply uphill you’re likely to have at least 35% sag at the rear and 5% to almost none at the front, if you’re seated on a bike with a slack seat angle (that’s what working hard to keep the front end down feels like). Try that with 160 travel front and rear and the bike’s attitude changes considerably. If you do more seated pedaling on the flat then set your bike up for that, but if more of your seated time is pointed uphill, the set your seated position up for that.
  • + 1
 Yes, exactly. The front and rear don't sag equally, but even if the front to rear *ratio* is constant on flat ground, the attitude change when climbing will be greater on a long-travel bike.

Let's say we always use 33% rear sag and 20% front. Imagine, for example, a bike with 1 mm of front and rear travel. If the rear sag goes to 50% and the front to 10%, essentially nothing changes with climbing. Now imagine the same change with 1 m of travel: that bike may have just flipped you over the back!
  • + 1
 @ReddyKilowatt: Actually the rear sag is usually higher than fork sag...
  • + 2
 The amount of thought that goes in to this makes me feel like a sucker. I just went to my bike shop, took their recommendation, and never looked back. My bike works perfectly based on what I'd expect.
  • + 4
 Some bikes look fast sitting still and then there is the POLE. It looks broken sitting still....
  • + 1
 but surely it's whether it's fast to ride not whether it looks fast sitting still
  • + 2
 I'm sure that's why bike Co's designed bikes with slack ST to match the slack HT to make it look good rather than ride good. I can see the product development conversation

Engineer: here is the new Bike, the seat tube angle has been optimised for performance, efficiency & comfort

Sales: yeah but guys, the consumer won't buy a bike with wonky angles

Marketing: Dude we can market a bike that looks like that

Engineer: ok you win here is the bike with chopper angles
  • + 1
 @Noserider5: it was a pun to be taken in jest.
  • + 1
 @Noserider5: never not been a fan of the new slack HA trail/enduro bikes. Had to do a cane creek ha set on my Canfield to make it feel less dead until I sold that. Agree that looks are not to be the priority to a bikes capabilities. But as you stressed, selling bikes are not always about effective engineering. Shred on!
  • + 1
 I'm actually liking the Pole more and more. I want to try one. I'm hoping i wouldn't like it since it's soooooo damn expensive Smile
  • + 1
 The other number worth looking at is the stem & handlebar as with backsweep and with a short stem and a bit of backsweep on the bars you wind up at a negative length, the 1 piece Hixon bars of Scott Sports got me thinking about this tidbit of set-up
  • + 5
 Oh I remember the old GT LTS...
  • + 2
 One thing I noticed when I moved to steeper seat tube was how much I use my seat for reference when descending. I had to get back slightly more on descending to get in the similar position on slacker seat tube angles.
  • + 1
 I wish bike manufacturers would make it standard practice to publish how they measure their bike's geometry. All they would need to to is to put a little footnote on the geo chart that says "geo measured at x% suspension sag front and y% rear with the saddle at z height." It would go a long way to informing the consumer how the geo numbers the manufacturer gives would actually equate to how they would set up the bike. Maybe those sag numbers are zero, but more info is always better, IMO. A small handful of companies do it now, but it would be better if more got on that bandwagon.
  • + 2
 The standard is to measure without any sag. It's not the most realistic standard, but at least it's a standard.
  • + 1
 i have a large 19 yt jeff with a 170 sdg, and i still need a 200. 4"of post sticking out sucks on steep dh, and feel like safdle could be higher on flat road or fire road stuff. im 6'1
  • + 0
 IMHO, a proper bike fitting would take place with the bike on two scales. Measuring the weights of the front and rear tires separately. Using those weights to develop a scope of balance for the rider. Some don't want as much upper body input requirements while others are fine with an all-ride pushup. Then use the 'reach' number for standing position info and go from there. It does seem the steeper angles feel better for stronger-shouldered individuals more often than with lesser-developed-shouldered individuals. This, for me, is to say I like to see the scope of balance points that a bikes geo allows and fit from there.
  • + 1
 On my 2015 reign I simply took the Giant offset to rear dropper, removed the seat and turned the post in the frame 180 deg. Put the seat on and slammed it forward. It climbs hills like an Anthem.
  • + 1
 But the cockpit is too short now. I just sold an L Reign 1 from 2015 yesterday (it was also a bit too small), so i know what i'm talking about.

Sizing up on the Reign was hard to do due to the long seat tube.
  • + 3
 i slammed the seat forward on my "outdated" 2016 trance and saved myself $5000
  • + 1
 meh- the steeper STA makes up for a slacker HTA in climbing ability, so my new bike climbs as well as my old trance, but descends better
  • + 1
 Your cockpit length is now too short, that's the issue.
  • + 1
 @Primoz: that's why i got the XL, feels great to me
  • + 1
 @arrowheadrush: What would you do if you were over 190 cm and couldn't size up? Razz

EDIT: what i'm trying to show that sizing up and slamming the seat forwards, while it does work, is not the best solution to the problem. It's the industry's job to take care of that.
  • + 1
 @Primoz: all i know is its a better solution then buying a new bike.
  • + 1
 @arrowheadrush: Don't know if it's a better solution, but it is a cheaper one for sure.
  • + 0
 Having been on steep STA bikes for a couple years now one of the biggest advantages I find is my center of gravity stays more consistent between sitting and standing and the bike's handling feels more predictable and carvy. The front rear balance has upped my cornering speed and confidence considerably.
  • + 2
 Another thing that seems to get ignored in this factor If you slam a seat forward or backwards on the rails .. the seat isn't in a good position for comfort due to rail flex
  • + 3
 Many modern bikes look like they've been in some kind of roof rack incident. :O
  • + 0
 I can't even believe I'm about to say this, but i think it makes sense to have another measurement in geo charts.

Effective Reach = Distance from center of seat to center of head tube*
*assuming seat it level to top of head tube

Essentially the red line Kaz drew from the seat to the head tube you see in their picture. Which is not reach as that line would be shorter since it start from the point where a vertical line from the BB intersects the horizontal line at the top of the head tube.
  • + 5
 What you're describing is pretty much effective top tube length, which as a measurement has been around forever?
  • + 5
 @Pedro404: ha! Right you are. Ignore this dummy
  • + 1
 edit: too slow typing on my response and got beat by @pedro404
  • + 0
 That said, why didn't effective top tube length get more play in this discussion?
  • + 1
 Isn't that ETT?
  • + 1
 That's already effective top tube length.
  • + 1
 While it may look similar to the effective top tube, it is actually not. Imagine the same ETT on an XL and XS bike. Now compare where the seats end up (height wise) and with current slack seat tubes how much forwards and backwards the seat moves in those cases. This would be something of a cockpit length measurement and i think would be quite useful.

The only catch is that it is seat height dependant and is hard to do for all people. Unless you had a 'calculator' on the bike's page that was interactive.
  • + 1
 @Primoz: That is ETT. A horizontal line to the middle of the where the seat would be. The variance from that is then dependent on seat height.
  • + 1
 @chriskneeland: I'm not talking about a horizontal line (which is independent from the seat height), i'm talking actual seat post head (for example) to top of headtube measurement for given seatpost extension. Or a horizontal and vertical value of the distance between the two points.
  • + 1
 "That brings us back to the original question – why is everyone obsessed with seat angles all of a sudden? "

Becasuse bike industry want's you to change your bike again.
  • + 2
 Not sure what the problem is, but a Lean back seat post, backwards is the answer
  • + 1
 No, the cockpit is then too short.
  • - 1
 "Are bikes so good now that reviewers are obsessing over details that barely matter?"

Nailed it, Kazimer.

Too short to be a Pinkbike write up, but henceforth, this shall be The Bible of ST Angles, and it's all you need:

130 mm or less: 75 degrees
140 mm-ish: 76 degrees
150+: 77 degrees

The shall be no decimal point degree values accepted.
  • + 1
 I can confirm that a steeper seat angle is better! Even just a 2 degree difference can have a huge impact on how a bike will feel
  • + 2
 Ride a hardtail. The longer the fork the more modern geometry you end up with. Hipster beard not required.
  • - 1
 Because we have Eagle here and the others with those rotor sized cassettes and long cages and chains, 30t chainring and so everyone thinks it's needed to climb up what is even a pain to walk up and still no one wants to flip backwards or just get off and push the bike up
  • + 1
 This was perfect.
  • + 1
 Something to be said for "brand" and riding bikes from brands you can align with? I know I choose bikes with that in mind sometimes.
  • + 4
 wut
  • + 1
 I really never thought about this much until bikes started getting longer and slacker. My question is who actually wants a slack seatpost? Seem's like nobody?
  • + 2
 Not as important as head tube angle and more subjective based on personal body dimensions and preferences.
  • + 2
 Just wait until some bike company comes up with a "seat tube angle standard" and nothing else will fit
  • + 2
 FWIW, I am not as big a fan of the forward seat position. It is harder on my knees. I usually run a setback seatpost.
  • + 1
 Chainstays also play in conjunction with Sa. I haven't seen that mentioned yet.
  • + 1
 How exactly?
  • + 1
 7 months on my 170mm PNW cascade fitted to Banshee Darkside with very slack seat tube and still in perfect working order.
  • + 0
 So what you're saying is. . . I can slap an angled seat post onto my 2011 Glory and call it modern geometry??? Interesting. . .
  • - 2
 Lets get away from using ( effective ) as a reference to do with seat tube angle. There is only one angle that has an effect on saddle position and that is the ( actual ) seat tube. I do understand that still will not be as informative as we want since there is no standard to where the actual seat tube angle originates from. Perhaps MFG's need to provide not only reach but saddle set back at a given saddle height. Maybe there are some sharp engineers/program designers out there that can create a program/grid chart that can be overlaid onto a frame drawing utilizing the center of the BB as the zero point. Then a potential consumer can input saddle height, axle to crown and bar height desired. Then the program will calculate stem length, spacers required, true reach to bar from BB center line and saddle set back. Create this program and license to MFG's for there potential buyers to use as a tool to decide sizing. For example my current bike I have determined that if I want my saddle 25mm father forward at current saddle side my seat tube angle needs to be 2 degrees steeper than what is listed by the MFG. But that is still not perfect. All MFG's list the so called (effective) seat tube angle in relation to the horizontal line that is being used for stack. This is all based on what MFG's show on there web site. So there may be some errors in my judgement if the geometry of seat tube angles is not accurate which just makes it even more difficult to understand fit from brand to brand or even size to size. I did write this prior to reading the article. My bad. It just a pet peave of mine that we use the term (effective). But the industry can and should do a better job. Hence the idea of a program that we all can use to better understand the real geo. with out actually having to lay our hands on a frame. I do appreciate the article.
  • + 1
 i still don't understand.
does actual seat angle really mean anything? it seems to me that your position relative to the bb (which i presume makes or breaks a bike's feel and fit) is determined by effective seat angle.
  • + 1
 The effective angle also plays a role since it in effect places the seat tube in horizontal space. Put the same seat tube more forwards and the effective seat tube angle will steepen.

Have a go here: docs.google.com/spreadsheets/d/10axDne-F31AshWyhrgYH5qVU6ytt3D32FHRGwCh4Oe4/edit?usp=sharing
  • + 2
 Pick a number....be a dick about it.
  • + 1
 Great article! To make it clear it actual seat tube measurement is taken with reference to the center top of the head tube?
  • + 3
 that's effective. actual is just the angle of the seat tube compared to the ground.
  • + 1
 Didn't take too much notice until I got a bike with a 76~ degree seat angle and boy howdy does it make a difference!
  • + 1
 Talking about seat angles is the mtb version of talking about the weather, i am a seat rail diameter man myself.
  • + 1
 Am I the only one getting tired of the slack geometry? Give me some poppy steepness!
  • + 1
 How about making a bike with an adjustable seat tube angle?
  • + 0
 THANK YOU!! FINALLY!! People really need to see how utterly useless and even wrong the reach number is by itself.
  • + 1
 I prefer circle discussions over angles . Diameter , radius oh yeah!
  • + 1
 Just tell me what angle I need @mikekazimer
  • + 1
 Od it something like adding volume spacers to xl shock air cans?
  • + 1
 @mikekazimer did i inspire you to write this.
  • + 1
 blah blah blah just ride your fucking bike
  • + 2
 des is ma zu krass :-)
  • + 1
 why people talk about? because people talk!
  • - 2
 Terrible and uninformed article. Please learn something about this subject before writing more.
  • - 1
 Just slide your seat forward,or pick a better bike next time
  • + 0
 Progress!
  • - 1
 Big wheel problems!
  • + 2
 First wheel problems.
  • - 2
 Jesus Christ, just ride your fucking bikes.
  • + 2
 Is it okay if we get bikes with proper fit first?
  • - 1
 Is*
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