# FSA 155mm crank arms.



## 2SLOFATASS (Mar 26, 2020)

Ordered a set of 155mm crank arms for winter riding, way to many pedal strikes on single track stopping the ability to reach the crest of the hills.

Anyone using 155mm on their e bike?


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## x-force (Jan 20, 2021)

i got my wife 150mm, but i would only go for it if you love pedaling at high cadance or have really short legs 
i can easily reach 140rpm with them and can clearly feel the e8000 loose power at that cadence. you also feel the loss in torque. comming from 175mm you need like 1 additional gear to compensate, but gain top speed like going from 11 to 10 sprocket, if you have the power.

clearance is definitly a plus. be aware that your seat height will also raise by 10mm, if you have 175mm currently. this is the way to get a longer dropper(200mm+ is genius).


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## PierreR (May 17, 2012)

Unlike gasoline engines, electric motors reach their maximum torque at near zero speed and their minimum torque at high rpm. At 140 rpm the motor will produce just about nothing for torque. Slowing the rpm a bit will give more torque from the motor. 
The torque that you produce with the 155mm cranks will decrease by 11% for the same effort you put into the 175mm cranks. The motor controller will match this so, one gear difference is about right. Your top end speed may or may not be affected. The motor will still reach maximum watts at some point.


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## 2SLOFATASS (Mar 26, 2020)

It seems the drive side arm has a clearance issue. It would hit the rear frame on rotation. Is it possible to bend the arm, and reshape the crank arm to fit? Or will the alloy crack or break?


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