Just recently went to 155 cranks. I have read that pedal and crank based power meters can be adjusted somewhat …say 165 but below that is tough. Any suggestions on power meters that are accurate and can accommodate short cranks 150-155 would be greatly appreciated. Thanks
I can’t see why a pedal based power meter would be affected by receding crank length (and I can imagine issues with crank based ones - I had some mechanical engineering in my degree)
I think power is calculated at the bb, rather than the force directly on the pedal. Imagine if you have a stuck cassette or pedal etc if you have a longer lever arm (greater leverage) you need to apply less force to free it. Lol, I have heard of some folk extending their spanner using a scaffolding pole so they have more leverage.
Assiomas work great. You can adjust the crank arm length on your cycling computer and on the Assioma app to accomodate different crank arms. 155mm should be no problem.
I agree - I can’t see there being a significant accuracy issue using a pedal based power meter on 155 cranks as long as the software/head unit allows you to set a length that short.
For reference, here are some sources on power meter types and the basics of how they actually work.
It’s not really about the BB other than the length of crank arm used (relevant to pedal PM in particular, since they can be used on many lengths) and the cadence RPM along with force measured by strain gauges on the pedal spindle.
Power Meters Explained - Every feature, technology & function you need to know - Bikerumor