Shorter E bike cranks

[Bowedw]

I would welcome advice on E bike crank lenght. I use 165 cranks on my normal cycles but have access to a Cube E bike with 175 cranks.
I have only ridden it once and feel the cranks are to long for me. Would swapping to 165 crank arms be a good idea? They are just about available as most places have sold out.
Any advice would be welcome.

[Jdsk]

Length seems to have less effect on power that we used to think.

So I'd be guided by comfort.

Jonathan

[brumster]

Ride what you're used to. 165mm very common on e- MTBs. Bosch ebike software at a dealer can reprogram the motor for use with shorter cranks if you make the change.

[PT1029]

I would go by comfort too, adding 10mm to your usual crank length brings the top pedal position 20mm closer to the saddle - 10mm at the top and 10mm at the bottom, so the saddle will always feel too low when your foot is at the top of the pedal stroke.
Don't forget if you fit shorter cranks, the bottom of the pedal stroke will be 10mm higher up, so you will be wanting to raise the saddle by 10mm. This may or may not cause issues for you when you want to stop and put your foot down. Some people get round this by always hopping off the saddle when they stop (say at traffic lights).

[Bowedw]

Thanks all for your input. I have changed the crank arms for 165mm ones now. Not ridden it yet but should be ok.

[swscotland bentrider]

I use 165 on my Ribble e bike. I normally rode 172.5. Absolutely fine. Any losses more than countered by motor. (And I have a Tiagra set for sale in bits and pieces )

[Jamesh]

Length seems to have less effect on power that we used to think.

So I'd be guided by comfort.

Jonathan

Power is torque X speed.

Longer crank more torque...

Longer crank tales foot longer to get round the crank so less power.... ???

[rogerzilla]

I think Jfsk was talking about biomechanical efficiency. If you put me on 100mm cranks or 200mm cranks, I'd probably develop less power as I couldn't use my muscles effectively.

[Jdsk]

I was talking about power output. The literature for road cycling is pretty consistent.

Jonathan

[swscotland bentrider]

I believe Wiggins rode 165 for the hour record.