Garmin vector: wrong crank lenght, how to compensate?

Triathlon Forum
1

i have had my crank length set wrong … does anyone know how can i modify a few of my files to see the correct readings?

or, roughly, the percentage up or down difference i might see between 170 and 172.5

thanks!

2

i have had my crank length set wrong … does anyone know how can i modify a few of my files to see the correct readings?

or, roughly, the percentage up or down difference i might see between 170 and 172.5

thanks!

Power is proportional to applied force X crank length X RPM, so all you need to do is scale your numbers by 170/172.5 (or vice versa, depending on which way you made the error).

3

Crap a whole 2-5 watts off depending on the power level. All your data is now crap.

Summary… I wouldn’t worry about it. Unless you it pushed you FTP over the 300W mark. Then it’s a big deal.

4

thanks for the info!

strange then, i’m seeing some major discrepancy between computrainer and bushido, and my vector. if i’m doing 300 on the trainer, the vector has me 325ish. at 400 it could be 430.

i thought it was crank length, but it seems it was set correctly after all. torque is right too.

5

Pedals are the first point of contact, tires on CT or bushido will be the last point.

There will be a difference between the two in terms of losses etc, not sure about 7%. Maybe though with the wrong crank input and measuring at pedal vs tire that might be 25 watts on 300.

Maurice

6

Bad data is still good data as long as you are consistent. Just fix the crank arm length and go for a ride. You should be able to get a close idea on how the two line up based on PE or Heart Rate vs watts.