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Similar to the "how much reach is too much reach ?" thread, how steep is too steep ?
I have a Honzo ESD with a 77.5° seat tube, which turns to about 79° at sag, and I really like it. Of course you're not gonna beat an endurance record with such a geometry but it's pretty great for going up and down (and really not so bad to wander around).
Reach (size L) is 490mm and +-505mm as sag.
Coming from a 2013 26", it felt really weird at first, the pelvis being more forward, close to vertical to the BB means that the upper body weight is much more spread between the saddle and bars (while with a 73° seat angle most of the weight is on the saddle, arms are just holding the bars with not much weight on them), and I'd get numbness in the hands. To feel comfortable I had to rise the bars quite a bit (to compensate for the fork sag as well) and with about 25mm of spacers and a 50mm rise bars (and 12° back sweep), it feels great, like driving a truck, with a very upward position (I don't like the hunched XC position).
Still, I'm thinking it could just be a bit better with a slightly more upward position and shorter toptube.
My theory (which may suck^^) is that by steepening the effective seat angle to 80° without modifying the reach this would make the toptube about 15mm shorter, and so if the back gets straight enough to hold the upper body weight by itself then there would be no weight on the arms. You'd may end up with pretty much a urban ride position for the upper body but still with a very long reach.
So all in all a pretty good position for climbing, and still a very long reach for going down.
Btw, despite the 77.5° seat angle, my saddle is as forward as possible. When I bought it I hesitated with the M but the reach is 465mm so I got the L.
I know a few bikes have a 80° steep seat tube (Privateer & Pole I think), but these are full suspended bikes, so the dynamic is quite different from a hardtail.
Anyone's got an idea on this theory ?
Said differently, do you think at 80° (or more) you can reach that spot where upper body is holding itself ?
Does anyone has experience with 80° seat angle ?
Is it too much ?
How much is too much ?
I have a Honzo ESD with a 77.5° seat tube, which turns to about 79° at sag, and I really like it. Of course you're not gonna beat an endurance record with such a geometry but it's pretty great for going up and down (and really not so bad to wander around).
Reach (size L) is 490mm and +-505mm as sag.
Coming from a 2013 26", it felt really weird at first, the pelvis being more forward, close to vertical to the BB means that the upper body weight is much more spread between the saddle and bars (while with a 73° seat angle most of the weight is on the saddle, arms are just holding the bars with not much weight on them), and I'd get numbness in the hands. To feel comfortable I had to rise the bars quite a bit (to compensate for the fork sag as well) and with about 25mm of spacers and a 50mm rise bars (and 12° back sweep), it feels great, like driving a truck, with a very upward position (I don't like the hunched XC position).
Still, I'm thinking it could just be a bit better with a slightly more upward position and shorter toptube.
My theory (which may suck^^) is that by steepening the effective seat angle to 80° without modifying the reach this would make the toptube about 15mm shorter, and so if the back gets straight enough to hold the upper body weight by itself then there would be no weight on the arms. You'd may end up with pretty much a urban ride position for the upper body but still with a very long reach.
So all in all a pretty good position for climbing, and still a very long reach for going down.
Btw, despite the 77.5° seat angle, my saddle is as forward as possible. When I bought it I hesitated with the M but the reach is 465mm so I got the L.
I know a few bikes have a 80° steep seat tube (Privateer & Pole I think), but these are full suspended bikes, so the dynamic is quite different from a hardtail.
Anyone's got an idea on this theory ?
Said differently, do you think at 80° (or more) you can reach that spot where upper body is holding itself ?
Does anyone has experience with 80° seat angle ?
Is it too much ?
How much is too much ?
Or just cuz' it probably wouldn't work because of the limited tilt range and lack of offset on most droppers, like my Reverb.
And I'm not yet willing to spend 110€ on the Fair Drop Best.
Study on seat angle
Anyone's got experience with 80° or +80°seat angle ?
Brilliant for going up hills, not the most comfortable on flat due to pressure on my hands. I have my saddle just forward of half way on the rails.
I'd say 80 is about the limit of seat angles, and really only suitable for enduro bikes that are going up steep climbs, where the seat angle helps keep you centralised. For a trail bike I think I'd want slightly slacker, or to move the seat back on its rails
Yes that's why I'm thinking about pushing it to 82° while keeping the same toptube length and enough stack so as maybe to alleviate weight on the hands, I don't know.
Toptube length could be around 610mm while reach could go close to 520mm.
The tricky thing could be that the steeper the seat angle, the higher the stack if you want to keep bars kinda level with saddle. But such a high stack could then be bad for the standing (descending) position, or maybe the long reach would make up for it.
I'm just worried such a steep seat angle could make the knee joint more acute and put more strain on it (the quad/spatula tendon) but I've done a quick simulation in a 3D software and it doesn't seem to change much from a 73° seat angle, it's mostly the hip joint that's opening (the thigh/leg angle goes from about 71° to 145° with both 73° or 82° seat angle, though my simulation is probably quite inaccurate and you've got to be careful with such dynamics as it's often what happens in the first few degrees that really matters, like LR in a kinematic).
So it seem ok but maybe i should ask for a physio opinion before getting any custom frame udnerway^^.
I had a custom HT being made with 77° SA static with a 625mm Stack static which gives respectively 78.2° and 616mm at SAG. Currently with a 40mm stem and 35mm rise bar I find the position to be quite a bit on the hands both up and downhill as I clearly overlooked the change in Stack with SAG. I planned my SA, HA and Reach at SAG but missed that one -_-
Anyway, I am waiting on a 35mm stem with a 60mm rise bar which should fix both issues. But I wouldn't go much further than a 79° at SAG because even without considering the current hand pressure thing, I like to sometimes ride without my hands or only grabbing the grips with my fingertips to change position during long climbs. Both are already kinda awkward with a 78.2° dynamic SA. Maybe the high rise will help with the fingertip grip but it won't change the no hand position. For a full suspension the dynamic of the frame is different so to achieve around 78/9° you need an angle between 79 and 81° depending on your travel and SAG.
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