bluntandy wrote:
FindinFreestyle wrote:
I think it is a function of leg length / seat height, upper to lower leg ratio, foot size, preferred setback (which itself is a function of..?), strength (FTP) of the rider, degree of pelvic tilt, preferred reach, overall mobility, total lifetime duration of riding, and the "X" factor. If there is one angle that drives it, it would have to be knee flexion. I have found I can make pretty good predictions of what the rider will choose, or give good recommendations solely from seat height. I've also found that there is pretty much nothing really too short for steady state aerobar riding.Thanks.
It would be nice if I could take a few simple measurements. Let's say seat height, leg length, clear position, torso angle and then come up with a simple formula.
It won't be that simple as I'm sure that using shorter cranks will then enable a change in all of the other variables.
Aarrgh!
I've got two years to figure it out.
Ok, I am trying to be gentle with rroof, but to be honest, I think you can use seat height as your primary driver and never look back. Other than out of the saddle climbing, there is virtually no downside to going shorter. Drive by gloat time.....At a 79cm seat height, I went down to 155s and won the VA 40kTT overall, and then the fastest bike split award at AG Nationals in 2012. Knowing what I know now, if somebody put a gun to my head and made me ride 145s or 140s, I would not be the least bit nervous about reduced performance. I recommend erring on the side of shorter.
You are right though, crank length effects everything. Really everything on the bike effects everything else, but crank length is the rug that ties the room together.