To judge whether the pulling force is appropriate, hold two steel wires in the palm of your hand and squeeze them hard. It's like putting an egg in your palm and squeezing it. If the steel wire is not deformed much, the tension should be ok. Of course, you have to pinch the steel wire of the whole wheel to know.

Generally, it takes a little experience to correct the rim. The more inexperienced people correct the rim, the greater the swing. So don't correct it easily. Find a mechanic to come to school.

Calibration requires a corrector, which is an iron ring, and then there are several gaps on it, which just match the copper head of the steel wire (the thing that connects the wheel and the steel wire).