Repairing a bicycle is a technical task. In the eyes of many people, repairing a bicycle is very troublesome, and the first choice for many people after any breakdown of the bicycle is still to go to the repair shop. But it's often just a small problem.
In order to avoid similar situations, I have sorted out several common faults of bicycles to help you judge the condition of bicycles:
1 ：There is a noise when pedaling
Reasons and suggestions：It may be that the three joints of the crank, axle core, and pedals are loose, or the sound is caused by friction. Take the loose crank bolt as an example. The crank bolt can be tightened. If the crank still sounds, remove it, apply a layer of grease on the shaft core, and then reinstall the crank.
2 ：The shifting line tube rubs against the frame and rubs off a piece of paint
How to solve: You can stick anti-friction silicone or rhino leather anti-friction belt on the contact place.
3 ：The flywheel is rusted
How to solve: If the rust is not serious, use more lubricating oil to prevent continued rust. At the same time, part of the rust will be removed from the chain during riding.
4 ：The rear derailleur keeps making a spiked noise
Reasons and solutions:
There has been a crash or collision that has caused the tail hook to deform. Check for deviation, if the deviation is serious, it is recommended to replace it directly.
The guide wheel has not been cleaned for a long time, and it is very dirty. Clean with detergent first, then drip lubricating oil for lubrication, wipe off excess oil.
The outer corner of the guide wheel is severely worn, and the obtuse angle is ground into a sharp angle, and abnormal noise may also be generated. In this case, it is recommended to replace the guide wheel.
5 ：Abnormal chain noise
Reason: The chain lacks oil, and it is caused by insufficient lubrication between the chain pieces.
Solution: Add chain oil or lubricant, and then wipe off the excess oil.
6 ：When using a certain gear ratio, the pedaling appears to jump teeth
Reason and solution: If there are foreign objects such as mud, weeds, leaves, branches and so on between the flywheels, dig them out. Because it will hinder the normal engagement of the chain and the flywheel. If not, the sprocket may have worn out, and the chain and the sprocket usually need to be replaced.