My chain is skipping on the rear sprocket, why is this happening?

A mid-drive motor places greater strain on the drivetrain than usual, which accelerates wear. When the chain skips on the sprocket, the issue is most likely due to using too high a gear. As the strain increases, the chain can create indentations in the sprockets, causing the chain to no longer sit properly on the teeth and instead skip over them.

The smallest sprocket (highest gear) is the weakest of them all, and when using it, the chain is in contact with the fewest teeth at one time. This is where the problem is most common, but depending on gear usage, it can occur with other sprockets as well.

Incorrect gear adjustment may also cause similar symptoms, but in such cases, the chain is searching for the correct position between the sprockets. Depending on whether the chain is trying to move to a larger or smaller sprocket, the gear cable must be loosened or tightened.

If the sprockets are worn like this, they should be replaced. It is usually a good idea to replace the chain as well, which can be confirmed by measuring the chain’s wear/stretch. For purchasing and installing spare parts, we recommend contacting the point of sale or our Helkama dealers.