1, the distance between front and rear wheels is widened and the chain is tightened.

2. Loosen the rear axle screw, then pull back the rear wheel to tighten the chain, and finally tighten the rear axle screw.

3. The bicycle chain is loose because the distance between the central axle and the rear axle is too close, so it is necessary to knock twice to open the distance.

Reason:

1, if the chain is loose or too long, it will fall off when riding;

2. Roulette roulette is unstable;

3. If the deflection angle between the toothed plate and the flywheel is too large, the chain will fall off;

4. The flywheel deviates from the rear gear angle, indicating that the chain is not straight enough;