PROWHEEL Ebike crank arm replacement, One Pair Crankarm 175mm forged 6061 alloy, square-taper fit L/R

PROWHEEL's Ebike crank arm with a square-taper spindle is a forged 6061 alloy replacement built for electric bicycles, available in six lengths and marked left/right for correct installation.

This crank arm is a direct-fit replacement designed specifically for electric bicycles that use a square-taper bottom bracket. Machined from forged 6061 aluminum, it balances strength and weight for reliable pedaling support on motor-assisted bikes. Before ordering, confirm the crank length and square-taper interface to ensure a correct match with your e-bike's drivetrain.

How do I pick the right crank arm length?

Choose a crank length that matches your original crank or your riding preferences; PROWHEEL offers six sizes from 140 mm to 175 mm. Shorter cranks suit smaller riders or higher cadence styles, while longer cranks give more leverage for larger riders or lower-cadence pedaling.

• Available lengths: 140, 152, 160, 165, 170, 175 mm.
• Measure center of pedal to center of spindle on your current crank to match size.
• Confirm e-bike compatibility — this crank is for electric bicycles only.

What spindle type and torque are required?

This crank arm uses a square-taper spindle interface—verify your bike’s spindle is square before purchasing. Tighten the crankarm bolts to the recommended torque range to ensure secure mounting without damaging the crank.

• Spindle interface: square taper (square hole).
• Recommended bolt torque: 35–45 N·m; do not exceed 45 N·m.
• Keep left and right crank arms matched during installation for proper function.

How do I install and orient the crank arms correctly?

Each arm is marked L or R to indicate left or right side; installing them in the wrong positions prevents correct function. Follow the torque specifications and confirm both arms are seated fully on the spindle to avoid play or premature wear.

• Left arm labeled "L," right arm labeled "R"—install accordingly.
• Ensure full engagement on the square taper and tighten to 35–45 N·m.
• Check for binding or play after first rides and re-torque if needed.

When should I replace the bottom bracket when swapping cranks?

If you replace the crankset more than once, consider replacing the bottom bracket too, since repeated crank changes can accelerate BB wear. A fresh bottom bracket ensures proper fit and extends the life of the new crank arms.

• Recommended: replace bottom bracket after multiple crank replacements.
• Worn BBs can cause loose fit, noise, or uneven wear on new cranks.
• Contact support if you encounter fitment or installation issues.

Who is this product for: Riders and mechanics who need a durable, straightforward square-taper crank arm tailored for electric bicycles. It's aimed at e-bike owners replacing a worn or damaged crank or those upgrading to a forged 6061 alloy arm in the correct length. Verify your bike uses a square-taper spindle and select the proper left/right orientation and length for a safe, reliable installation. If you need help choosing the right size or encounter any installation questions, PROWHEEL customer support can assist with fitment guidance and solutions.