I have been doing a lot of research into crank length, I have a 172.5mm crank which I find my knees come up too high, and sometimes I get a bit of back pain. I have a Scott Speedstar 2017.
I am 175cm tall, and an internal leg length of 78cm. I looked at the following video:which was invaluable but, I find I am around 164mm for a crank when using the 9.5% of my height.
should I go down from 172.5 to 165? or just move down to 170mm? as was said at the end of the video, "Modern bikes are designed around 170 to 175mm long cranks"
- should I goto 165mm or 170mm long cranks? I know I need a shorter crank, just how much shorter is the question :)