Cranks and crank arms for fitness equipment

What is a fitness machine’s crank?

The crank, also called a crank arm, connects the pedal to the bottom bracket axle or drive system. As you pedal, the cranks transfer your pedalling movement to the flywheel or drive system. Cranks are mainly used on exercise bikes and indoor cycles, but also appear in the drive systems of certain cross trainers.

When should you replace a crank?

Replacement may be needed if the crank is bent or cracked, no longer stays securely on the axle or has damaged pedal threads. Play, creaking or sideways movement while pedalling may also indicate a problem with the crank or bottom bracket axle. Stop training if the crank is visibly damaged or comes loose.

Left and right cranks

Many fitness machines use different left and right cranks. The side is indicated from the normal training position on the machine. Always check the designation in the product name or parts list, as a left crank generally cannot be used as a right crank. The pedal thread direction may also differ between sides.

How do you choose the right crank arm?

First identify the brand and exact model designation of the fitness machine. Then check whether you need the left or right side and compare the drive axle connection, crank arm length and pedal thread. For some products, a measurement in the name refers to the connection; this does not automatically make the crank suitable for every machine with the same measurement.

Are fitness equipment cranks universal?

Most cranks are designed for a specific machine or product range. Differences in axle connection, orientation, length and thread may mean that a similar crank still does not fit. Where possible, choose a component explicitly listed for your fitness machine.

Is the crank or bottom bracket axle faulty?

Play while pedalling is not always caused by the crank. The problem may also lie in the bottom bracket axle, bearings, fixing bolt or pedal. Check where the movement occurs before ordering a component. Damaged pedal threads are often in the crank arm, while noticeable play around the pivot may indicate axle or bearing wear.

Installing a crank safely

Fit the crank in the correct position on the drive axle and use the specified fixing hardware. Tighten the connection securely following the manufacturer’s instructions. Also install the left and right pedals on the correct sides to avoid thread damage. After a short test ride, check again that all connections are secure.

Browse our pedals and pedal parts or explore our full range of fitness equipment drive system parts.