I disappeared down the internet rabbit hole looking for an answer
EWS professionals ride surprisingly short bikes – for good reason [https://enduro-mtb.com/en/enduro-race-bike-mtb-review/,](https://enduro-mtb.com/en/enduro-race-bike-mtb-review/,) [https://www.stevehoggbikefitting.com/](https://www.stevehoggbikefitting.com/) , [https://www.renehersecycles.com/myth-5-an-upright-position-is-more-comfortable/](https://www.renehersecycles.com/myth-5-an-upright-position-is-more-comfortable/)
^ with sites like these for a start
some of my observations
1\. The forward leaning torso angle of a road cyclist is not all about aerodynamics. Many of our muscles are used to keep us upright in a running and walking position; however, when those muscles do not have to do the work of supporting us upright, it spares energy and movement within the torso to breath deeper (such as you see when people squat over to recover their breath after running up stairs, or are having trouble because of some health problem)
2\. When standing on the pedals, if the front centre is too long, your body has to do extra work to weigh the front tire adequately. Ideally, when standing on the pedals in neutral position, you can lift your hands and still be balanced over your feet and not tip forward, or use other muscles to maintain balance (partially reducing range of motion)
3\. Riders have all different pedaling styles (heel droppers, toe tippers, flat footers, plus mid foot or ball over spindle variations) and seated postures (upright, leaning forward from the top of an upright pelvis, to a leaning forward pelvis with extended horizontal torso...). All these variation affect seat behind BB placement, seat angle and seat to BB length, but ideally, as with standing, you should be balanced enough to lift your hands off the bars without straining pelvic and torso muscles to maintain balance (tri-bars are an exception, but there still needs to be balance and lack of muscle strain to maintain position).
4\. Road bike races can have steeper climbs than IMBA/North Shore trail standards. There are even road races that are just hill climbs, or up and over a mountain pass then plummet back down to the valley in a tuck. So mtn biking is not as much of a special case as many think.
5\. As Tehllama42 already posted. There is a compromise between reducing tendency to endo vs front tire grip (for me after experimenting with an angle adjust headset, I chose front tire grip, since for an endo I can usually see it coming and anticipate; whereas, for cornering at the limit there is often no warning)
6\. Road sprinters use a steeper seat tube than road tour-ers, since the sprinters need to reduce the transition between seated and standing (triathlon is even more extreme, but it is not about being dynamic on the bike).
So, even if my climb angle is 10 to 20 degrees, I don't think a 83 to 93 degree seat tube angle will be a good idea.
March 30, 2021, 8:41 a.m. - taprider
I disappeared down the internet rabbit hole looking for an answer EWS professionals ride surprisingly short bikes – for good reason [https://enduro-mtb.com/en/enduro-race-bike-mtb-review/,](https://enduro-mtb.com/en/enduro-race-bike-mtb-review/,) [https://www.stevehoggbikefitting.com/](https://www.stevehoggbikefitting.com/) , [https://www.renehersecycles.com/myth-5-an-upright-position-is-more-comfortable/](https://www.renehersecycles.com/myth-5-an-upright-position-is-more-comfortable/) ^ with sites like these for a start some of my observations 1\. The forward leaning torso angle of a road cyclist is not all about aerodynamics. Many of our muscles are used to keep us upright in a running and walking position; however, when those muscles do not have to do the work of supporting us upright, it spares energy and movement within the torso to breath deeper (such as you see when people squat over to recover their breath after running up stairs, or are having trouble because of some health problem) 2\. When standing on the pedals, if the front centre is too long, your body has to do extra work to weigh the front tire adequately. Ideally, when standing on the pedals in neutral position, you can lift your hands and still be balanced over your feet and not tip forward, or use other muscles to maintain balance (partially reducing range of motion) 3\. Riders have all different pedaling styles (heel droppers, toe tippers, flat footers, plus mid foot or ball over spindle variations) and seated postures (upright, leaning forward from the top of an upright pelvis, to a leaning forward pelvis with extended horizontal torso...). All these variation affect seat behind BB placement, seat angle and seat to BB length, but ideally, as with standing, you should be balanced enough to lift your hands off the bars without straining pelvic and torso muscles to maintain balance (tri-bars are an exception, but there still needs to be balance and lack of muscle strain to maintain position). 4\. Road bike races can have steeper climbs than IMBA/North Shore trail standards. There are even road races that are just hill climbs, or up and over a mountain pass then plummet back down to the valley in a tuck. So mtn biking is not as much of a special case as many think. 5\. As Tehllama42 already posted. There is a compromise between reducing tendency to endo vs front tire grip (for me after experimenting with an angle adjust headset, I chose front tire grip, since for an endo I can usually see it coming and anticipate; whereas, for cornering at the limit there is often no warning) 6\. Road sprinters use a steeper seat tube than road tour-ers, since the sprinters need to reduce the transition between seated and standing (triathlon is even more extreme, but it is not about being dynamic on the bike). So, even if my climb angle is 10 to 20 degrees, I don't think a 83 to 93 degree seat tube angle will be a good idea.