Crank arm loose... falls off / cannot be loosened

Crank arm falls off

One problem that is less expected is the loosening or loosening of the left crank arm. It is not a Stromer-specific problem and also happens with other brands. The problem announces itself and does not happen immediately.

Cause

The cause is usually the assembly. The screw lock applied at the factory is not very tight, so that the crank can come loose even if it is fitted correctly. Furthermore, the screw connection is sometimes incorrectly greased (because this is sometimes the case with other cranks).

Repair

Crank arm cannot be released

Solution variant 1: Drive a few meters.

Solution variant 2: Video 1 | Video 2
The design of the crank arm is 'self-dismantling' (self-destruction system) and requires no special tools.

Solution variant 3Treat the crank from behind with a little rust remover (e.g. WD 40) and then leave to work for 24 hours. Alternatively you can use Coca Cola - no joke. Then lightly tap the crank arm around the bottom bracket axle with a rubber or soft-face mallet - the crank should then come loose.

Solution variant 4Heat the crank arm around the crank axle with a hot air gun - the crank should then loosen.

Solution variant 5Use a professional squeegee.