Thoughts on modern frame geometry trends? Steep seat tubes? High stack?

[srf0638]

With the topic of seat setback/fore-aft, don't just put your saddle as forward as you can as it can be very dangerous. Here's a very nice read regarding setting your saddle fore-aft position.

I actually copped a knee injury from saddle too far forward (plus maybe too low) and I still say "very dangerous" is kinesophobic Hoggwash. It's not felling timber or BASE jumping, you know?

He used to bang on about taint pressure with forward fits, which I think was probably a legitimate concern in the original Selle Italia Flite days but significantly mitigated by ISMs and so forth.

[SLockwood]

Most people who have spent a lot of time working on progressive fit and the bike designs don't support the idea of a higher stack. Just look at the Ridley Noah Fast 3.0 and the Factor One. It's a half-truth popularized by influencers.

I would say that positions are more stack-sensitive because you really want to minimize the back angle and then drop the arms more or less straight down, or very slightly forward, then have your forearms parallel to the ground in the aero-hoods position. This is to manage triceps fatigue and lower the frontal area.

Fair point, I'll blame my morphology. I considered the Noah Fast but had to rule it out, I would need an xs for stack height but id be at or exceeding minimum insertion for the seatpost so I had to rule it out.

[Dark17]

I actually copped a knee injury from saddle too far forward (plus maybe too low) and I still say "very dangerous" is kinesophobic Hoggwash. It's not felling timber or BASE jumping, you know?

He used to bang on about taint pressure with forward fits, which I think was probably a legitimate concern in the original Selle Italia Flite days but significantly mitigated by ISMs and so forth.

I said very dangerous because it affects handling as the weight is shifted at the front of CoG of the bike, which in turn make the bike more sketchy to handle in descents or in a group ride. It also messes up with your body's biomechanics. We had a discussion with a Steve Hogg approved fitter that the reason why there's a lot of crashes lately is because of the saddle far too forward. There's now a UCI ruling that saddle setback should not exceed below 50mm.

"It's not felling timber or BASE jumping, you know?" - Well yes, but descending in 60kph - 80kph or even 100kph+ will cause you a lot of injuries too, or worse you even die.

Pretty dated article. TT and Tri guys have their saddle way further forward. They don’t seem to have any issues. If anything, since I slammed saddle all the way forward I’ve had less discomfort than ever. Opens up the hip angle. More power, more comfort. I think more people should at least try it.

If that's outdated for you, [url = https://www.youtube.com/watch?v=zqc2d2o0N-Y]this [/url]is a most recent discussion/podcast about saddle setback. Colby Pearce is the bike fitter for EF Education team, and he was also mentored by Steve Hogg. And as the title of the article said, it's for road bikes.

I actually tried to get my saddle as forward as possible and it just overloaded my hands and made them numb during rides. Yes, my pedaling is good but I feel that the balance is too forward that I can't ride with no hands. And i already have a 120mm handlebar length and very slammed stem. It was corrected by my fitter when he set my saddle a little bit back and I have the most comfortable position I had- cores are getting engaged and few to no pressure on hands when putting down some zone 2 power. In short, a very comfortable and sustainable position on the bike- one reason why on my next aero bike, I will request a comfortable position as possible without compromising the speed.

[Sakizashi]

I said very dangerous because it affects handling as the weight is shifted at the front of CoG of the bike, which in turn make the bike more sketchy to handle in descents or in a group ride. It also messes up with your body's biomechanics. We had a discussion with a Steve Hogg approved fitter that the reason why there's a lot of crashes lately is because of the saddle far too forward. There's now a UCI ruling that saddle setback should not exceed below 50mm.

There is some bad physics terminology and it’s likely misleading. Gravity is not the only force—what you care about is center of mass and how the moments change as the bike turns and leans. Moving the rider forward is not inherently dangerous as long as you compensate for it by changing the axis of rotation during the motion. This ends up being really complicated, but the summary is to fix this you reduce the horizontal distance between the BB and the rear wheel, increase the horizontal distance between the BB and the front wheel, or do both depending on what is needed.

The reason we tend to abstract this into F/R weight balance is to simplify things. To be generous let’s say that something like 57-62% of the weight on the rear is ideal.  For smaller riders a progressive fit bike like the Noah Fast 3.0 is actually moving the COM back in terms of F/R balance as measured at the wheels. For riders on the largest size they are actually more rear biased than ideal today. The Noah also improves that. Basically it’s a fix all the way around. Of course the cost is a new fit and some physiological demands there.

Furthermore, I don't think there is evidence that forward fits are causing more crashes, though one could theorize that it could have been a contributing factor in incidents like Chloe Dygert’s TT crash at Worlds a number of years back. The reason for this is that the performance envelope of the system changes, it’s not some static thing. Certain turning and braking scenarios, for example that were fine before might be compromised; but I haven't heard of any actual analysis done that shows that in the cases of crashes, rider positions pushed the systems outside of the limits that a dynamics model suggested was safe. If you have, please share it.

The UCI 5cm setback rule is also gone. Not a thing anymore.

[Sakizashi]

So, considering a typical road fit, how did you guys adjust the bar position as you moved the saddle forward if at all? One would assume you also bring it forward buy maybe that's actually a bad idea in terms of shifting weights on the hands / triceps fatigue.

No one really answered your question, so I will give it a go. It’s easier to do if you have something like. Kickr bike or Zwift bike with the mutiple crank length options.

Step 1: Move the saddle forward.
I personally would do it until the pedal stroke feels like it’s getting a hitch going over the top. When that happens, you have 2 options. First, move the saddle back; second, lower the saddle. Both of them will close up the hip. They will load the glutes vs. quads differently. I would play with this across a few rides that push you into a fatigued state. I would pick the one that results in more consistent stroke and hip movement, comparing your results early in the ride and when fatigued. This is your new saddle position.

Step 2: Work out the back angle and check crank length.
You want the back angle to be as low as possible. Luckily, this one is pretty simple. You will feel when it’s too low to sustain, so just move the bars up. If your knees are moving out or in as you pedal, I would consider a shorter crank and repeat Step 1. I think of step 1 as moving the range of motion. A shorter crank reduces the range, so if you do move to a shorter crank, you need to go back to step 1. The reason you should consider these together is that this is a paired optimization with a clear condition for checking the fit again.

Step 3: Set the front end.
I think for a progressive fit this becomes straightforward. Using the back angle from step 2, drop the upper arms straight down or slightly forward with the forearms flat. Where your hands go is where you need the hoods. Find a stem-and-bar combo that works.

Step 4: Iteration to a new overall fit baseline.
You need to reconsider steps 1 and 2 in light of step 3. This is functionally more of a check to make sure everything is still working as you expect. If you find that hand or wrist pressure is intolerable, that might be a reason to go back to Step 1, though I feel like even for people spending 6+ hours on the bike at a time, it's pretty rare. This is also the point where you should take the bike outside and check things like descending and uphill sprints to make sure the bike still feels good,

Step 5: Front end optimization.
Once you feel confident that you have a new fit baseline, this is about taking notes as you ride and adjust accordingly. E.g., Upper back pain at the end of long rides, between the shoulders, might mean your position is too low. This is also where it might be a good idea to check aero things like arms coming out.

Hope this is helpful. It’s more or less how I do it.

Edit: I did this on a phone last night, so I fixed some formatting after realizing it's a bit hard to follow.

[Uberflo]

Thanks that is very helpful. I will try some AI video analysis with ChatGPT after this tutorial.

[Eddy_Twerckx]

So, considering a typical road fit, how did you guys adjust the bar position as you moved the saddle forward if at all? One would assume you also bring it forward buy maybe that's actually a bad idea in terms of shifting weights on the hands / triceps fatigue.

I increased my stem by 20mm, and probably should have gone 30mm longer. Dropped 1cm spacer. Saddle was raised so that the BB to saddle surface was the same. The best way to think of it is taking your old fit, then rotating it around the BB (gif below). It's a little more weight on the hands but not much. Does require a little more core strength but again, not a lot.

Exaggerated but shows the basic idea: https://imgur.com/tuyRbeX

I thought the weight on the hands would be too much but even 6 hour rides I'm fine.

[Eddy_Twerckx]

I said very dangerous because it affects handling as the weight is shifted at the front of CoG of the bike, which in turn make the bike more sketchy to handle in descents or in a group ride. It also messes up with your body's biomechanics. We had a discussion with a Steve Hogg approved fitter that the reason why there's a lot of crashes lately is because of the saddle far too forward. There's now a UCI ruling that saddle setback should not exceed below 50mm.

"It's not felling timber or BASE jumping, you know?" - Well yes, but descending in 60kph - 80kph or even 100kph+ will cause you a lot of injuries too, or worse you even die.

If that's outdated for you, [url = https://www.youtube.com/watch?v=zqc2d2o0N-Y]this [/url]is a most recent discussion/podcast about saddle setback. Colby Pearce is the bike fitter for EF Education team, and he was also mentored by Steve Hogg. And as the title of the article said, it's for road bikes.

I actually tried to get my saddle as forward as possible and it just overloaded my hands and made them numb during rides. Yes, my pedaling is good but I feel that the balance is too forward that I can't ride with no hands. And i already have a 120mm handlebar length and very slammed stem. It was corrected by my fitter when he set my saddle a little bit back and I have the most comfortable position I had- cores are getting engaged and few to no pressure on hands when putting down some zone 2 power. In short, a very comfortable and sustainable position on the bike- one reason why on my next aero bike, I will request a comfortable position as possible without compromising the speed.

Still disagree with it. Newer bikes are getting longer wheelbases and front centers to acommodate the CoG shift. And if you have adequate core strength it shouldn't overload your hands. If it does, you need to work on core strength. Bike handling and descending are skill issues. Moving the saddle forward doesn't, or shouldn't, negatively affect the handling to the extent that it's dangerous. You're not that far forward where it should cause an issue. You can argue the safety of the supertuck, but with that you're putting your CoG way further forward than is even possible with the progressive fit.



Look how far forward Froome is. That CoG is at least 10-20cm (yes cm) further forward than I could ever get with my progressive fit. Saying that the progressive fit is unsafe or dangerous is just a skill issue on your part. With the saddle setback rule, you just can't shift your weight far enough forward to cause problems with handling.

I'm sorry but Hogg's thought about bike fit are simply just incorrect.


Also, the UCI rule is 0mm setback from BB, not 50mm anymore. Changed recently.

[Dark17]

Core strength will give you up eventually, and not all riders put 400 watts for hours to hold you ip to your position so you won’t overload your hands. Well that’s for your average fred anyway. If you constantly do 400+ watts then slam that saddle forward. Else, try to find a nice balance between holding your position up for hours without compromising the front end of your body which is the arms. As I’ve said, I also had my saddle far forward as possible. It feels great for the first few hours then eventually, my body hurts all over. My fitter then found a nice balance with my fore-aft and it did wonders a lot. Not saying my saddle is in between or all the way back, it is still in front with 0 offset seatpost, just not slammed all the way forward. The actual danger of getting your saddle way forward is the control on the descents. I am still putting my ass back of the saddle when there’s a 90 degree descent because fuck going on front of your saddle on that, I ain’t doing that even in a race lol.

What I am trying to say is, find a nice balance on your fore-aft. It may work for you or the other riders, but it ain’t for everyone. If your zone 2 is a nice 280 watts then I think you’ll benefit on slammed forward saddle. Else, a nice balance would be much better.


And you provided an example that was already banned by UCI. I remember that there was so many freds in my country who did that and they ended up crashing. Also saw a lot of accident vids because they try to ride like Froome. As Colby said, don’t copy the pros position, we ain’t pro.

[Eddy_Twerckx]

Core strength will give you up eventually, and not all riders put 400 watts for hours to hold you ip to your position so you won’t overload your hands. Well that’s for your average fred anyway. If you constantly do 400+ watts then slam that saddle forward. Else, try to find a nice balance between holding your position up for hours without compromising the front end of your body which is the arms. As I’ve said, I also had my saddle far forward as possible. It feels great for the first few hours then eventually, my body hurts all over. My fitter then found a nice balance with my fore-aft and it did wonders a lot. Not saying my saddle is in between or all the way back, it is still in front with 0 offset seatpost, just not slammed all the way forward. The actual danger of getting your saddle way forward is the control on the descents. I am still putting my ass back of the saddle when there’s a 90 degree descent because fuck going on front of your saddle on that, I ain’t doing that even in a race lol.

What I am trying to say is, find a nice balance on your fore-aft. It may work for you or the other riders, but it ain’t for everyone. If your zone 2 is a nice 280 watts then I think you’ll benefit on slammed forward saddle. Else, a nice balance would be much better.


And you provided an example that was already banned by UCI. I remember that there was so many freds in my country who did that and they ended up crashing. Also saw a lot of accident vids because they try to ride like Froome. As Colby said, don’t copy the pros position, we ain’t pro.

I don't think I remember a single crash in the super tuck. Much like a lot of the UCI's "safety" rules, it's not really about safety.

And my point about the super tuck is that they are so much further forward than you're getting with a progressive fit. The super tuck is safe, and that's 20cm further forward than my position. Your claim that a progressive fit is dangerous is wildly inaccurate. And that's proven by the super tuck which is even further forward. If you think a forward saddle is dangerous, that's a skill issue, not inherent with the position. The position in itself isn't any more dangerous or compromising than a rearward position. The position doesn't make one safer than the other, the rider does. If a rider makes the forward position unsafe, the same rider will be unsafe with a rearward position. What's unsafe is going beyond your personal skill level.

The thing with the progressive fit is that it's still pretty rearward. You're at most, equal with the BB. I'm still 5cm behind. You seem to think this fit puts you in front of the BB or somehow shifts your weight forward enough to make it unstable, neither of which are true. You're still behind the BB. It's more about opening your hip angle to allow higher power output and more comfort. Like any fit change it'll take some getting used to. But to say it's unsafe or dangerous is just wrong. You're fear mongering.

[Sakizashi]

Core strength will give you up eventually, and not all riders put 400 watts for hours to hold you ip to your position so you won’t overload your hands. Well that’s for your average fred anyway. If you constantly do 400+ watts then slam that saddle forward. Else, try to find a nice balance between holding your position up for hours without compromising the front end of your body which is the arms. As I’ve said, I also had my saddle far forward as possible. It feels great for the first few hours then eventually, my body hurts all over. My fitter then found a nice balance with my fore-aft and it did wonders a lot. Not saying my saddle is in between or all the way back, it is still in front with 0 offset seatpost, just not slammed all the way forward. The actual danger of getting your saddle way forward is the control on the descents. I am still putting my ass back of the saddle when there’s a 90 degree descent because fuck going on front of your saddle on that, I ain’t doing that even in a race lol.

With respect to your experience — I think it reflects going halfway in figuring out a forward fit. It sounds like your setup was sort of in between and then you went back. Totally fine; it's not going to work for everyone, but the forward fit doesn't add that much weight to your hands because you shouldn't have much weight on your hands to begin with. If you have 10% of your weight on your hands going forward a few cm, and having that change to like 12% or even 15% shouldn't be a meaningful change.

I also am not really loading my core; my tummy is pretty relaxed. I do think there is bias towards fitter riders, but at this point it's more about self-selection. Connected to this point, I am increasingly thinking that this fit offers pro-like results in muscle recruitment and aero without requiring a pro's physiology, rather than being a significantly better option for folks at the highest end of racing. In other words, it's a way to get closer to a fit a WT pro would use when you lack the fitness and physiology of a WT pro.

It's a small thread to grasp, but if your body is hurting all over, is that obviously a bad thing? Or is that a sign that you are using different muscles? Worth figuring out, especially since you seem to be a Colby Pearce fan and his whole thing is about using the whole body on the bike.

P.S. I think there is plenty of video of people crashing over the bars in supertucks to suggest that doing that might contribute. Not sure there is even any analysis out there that suggests that riders who are on forward fits crash more than those that don't. Let's not conflate the two here.

[crazyravr]

Reading about this saddle forward and descends, I just have to chime in. There is a big difference descending at 4-5% vs 10-15% when doing the steep downhills, I have to slide myself all the way back nearly off the seat, otherwise and especially when I try to brake even slightly, I get a major frame shimmy. Took me a while to discover how to stop this, so now I have more confidence.
And that photo of Froomie, he would not be doing this on a steep descent. His center of gravity is very low and thats all good for the nice fast flowing downhills.

Also, to find the right fit, slam your saddle forward and then ride at a hard tempo. Can you remove your hands and not collapse? If you cant, move the saddle back slightly until you can. IF you cannot remove your hands and not collapse at any time, you have a wrong frame.

[jfcb]

I don't think I remember a single crash in the super tuck. Much like a lot of the UCI's "safety" rules, it's not really about safety.

And my point about the super tuck is that they are so much further forward than you're getting with a progressive fit. The super tuck is safe, and that's 20cm further forward than my position. Your claim that a progressive fit is dangerous is wildly inaccurate. And that's proven by the super tuck which is even further forward. If you think a forward saddle is dangerous, that's a skill issue, not inherent with the position. The position in itself isn't any more dangerous or compromising than a rearward position. The position doesn't make one safer than the other, the rider does. If a rider makes the forward position unsafe, the same rider will be unsafe with a rearward position. What's unsafe is going beyond your personal skill level.

The thing with the progressive fit is that it's still pretty rearward. You're at most, equal with the BB. I'm still 5cm behind. You seem to think this fit puts you in front of the BB or somehow shifts your weight forward enough to make it unstable, neither of which are true. You're still behind the BB. It's more about opening your hip angle to allow higher power output and more comfort. Like any fit change it'll take some getting used to. But to say it's unsafe or dangerous is just wrong. You're fear mongering.

I don't agree with this at all.

First, the supertuck didn't cause crashes because riders only used it solo or in tiny breakaways when they felt safe doing so. No pro was ever supertucking down a steep, twitchy descent in a group.

Second, any fit or position that shifts too much weight over the front wheel is dangerous by default. Unloading the rear tire ruins rear-brake traction, making quick emergency stops in the peloton way harder. It also ruins control—MTB riders lean behind the saddle on technical descents for this exact reason.

Also, rider height matters here. A tall rider creates much more leverage than a small rider, so a progressive fit impacts their weight distribution far more.

To avoid the front-end weight distribution, the actual solution is extending the front-center length of the frame to maintain stability without forcing poor rider posture. This is a must for the modern frames who want to make this solution possible.

[Sakizashi]

Reading about this saddle forward and descends, I just have to chime in. There is a big difference descending at 4-5% vs 10-15% when doing the steep downhills, I have to slide myself all the way back nearly off the seat, otherwise and especially when I try to brake even slightly, I get a major frame shimmy. Took me a while to discover how to stop this, so now I have more confidence.
And that photo of Froomie, he would not be doing this on a steep descent. His center of gravity is very low and thats all good for the nice fast flowing downhills.

Also, to find the right fit, slam your saddle forward and then ride at a hard tempo. Can you remove your hands and not collapse? If you cant, move the saddle back slightly until you can. IF you cannot remove your hands and not collapse at any time, you have a wrong frame.

Two things.
1. Regarding the front end "shimmy." This is not normal at all and is a totally different issue. I recommend you find a bike that doesn't do this, as it's not really something you hear about with modern road bikes built up correctly. If your bike is built correctly, what you are experiencing is exiting the stable condition of the bike-rider system and entering a state where energy is stored in the system. This happens with most modern road bikes at a suitably low speed that the rider can easily manage it. This could be an issue on slacker bikes (e.g., taking an MTB on a high-speed road descent, maybe a gravel bike too if it's super slack and high trail), but is relatively unheard of on modern road bikes.
2. We covered the myth of balancing on a bike on a trainer a page back. It's a dated and unrealistic test, built on unreasonable assumptions.

Also, rider height matters here. A tall rider creates much more leverage than a small rider, so a progressive fit impacts their weight distribution far more.

To avoid the front-end weight distribution, the actual solution is extending the front-center length of the frame to maintain stability without forcing poor rider posture. This is a must for the modern frames who want to make this solution possible.

Agree with the solution. The rider height, though, isn't an inherent problem; it is a result of the UCI rules restricting wheelbase. The effective STA is still moving the rider proportionally back relative to their height, so assuming the same back angle the COM of the system also moves proportionally back. You just need to manage the wheelbase to keep everything balanced. If you are worried about stability in the forward/rear direction you need to scale both the CS and the FC too...so the bike gets even longer...

[hubba]

As I've moved my fit forward I've gone up a bike size. The old pro trend of downsizing a bike and running a very long stem is not ideal with this fit. But if you choose the frame geometry for it I see no handling compromises. It's obvious not only the seat tube can change you need a longer front center too. I wouldn't mind seeing a bit slacker head tube angles too on road bikes.