I’ve been experimenting with different crank lengths on my 24" muni, and have come to believe that I need to change the seat height whenever I change crank lengths. Is this a normal thing? Do you do this? It makes sense (to keep leg extension roughly the same), but it just never occurred to me before.
Here’s the rub: Say you go to shorter cranks and raise your seat proportionately. If you’re not highly skilled, this makes mounting noticeably harder, raises your center of gravity, throws off your balance, and generally makes makes you fall on your face a lot more often.
You are correct. If you change (for example) from 150mm to 125mm, you will need to raise your seat approx 1 inch to make up for it (to keep your riding rotation the same). Yes, this affects other aspects of riding as well. Takes a little getting used to. This is one thing that has kept me from getting dual-hole cranks – I don’t relish the idea of changing my seat height all the time.
Yup. My seat height change is generally slightly greater than the change in crank length. I make graduated markings on my seatposts to make it easier to know how far to raise/lower the seat when changing the cranks.
I recently went from 145mm to 125mm Qu-Ax cranks (on a 29er) and yeah, I had to raise the seatpost up about an inch. At first I was worried I’d notice the difference when mounting, but well, I didn’t I noticed the weirdness of having no leverage to control the wheel more.