When should bicycle consumable parts be replaced

Many parts of bicycles will suffer from wear, aging, deformation and other losses during long-term riding. These undesirable phenomena will reduce the working performance of various mechanical components to varying degrees, thereby reducing the comfort during riding, and the loss of some components may also have a negative impact on riding safety.

The teeth of the brand new chainrings and flywheels are not too sharp, and their tops are generally flat or arc-shaped, which can be closely occluded with the chain.
The severely worn chainwheel, flywheel and rear dial guide wheel will become very sharp, which will weaken the degree of engagement with the chain, resulting in abnormal noise, weakness when exerting force, slow or inaccurate gear change response, etc. A bad phenomenon in the riding experience, and may cause "tooth skipping" (that is, the chain does not catch a certain tooth of the chainring or flywheel, and directly "jumps" to the next tooth" when exerting force, which affects safety consequences!
So, don't wait until the gear is worn so that it can pierce your fingers, and then consider replacing it with a new one!

I wonder if you know that the chain will be stretched after a long time! The elongated chain will affect the occlusion with the flywheel, chainring and rear dial guide wheel, and may also cause abnormal noise, weak force, slow or inaccurate shifting, and skipped teeth. And if you are a player with strong leg strength, then in a strong riding such as climbing, it is very likely that the aging chain will be broken, causing great danger!
Please go to the car shop regularly and use professional tools such as chain calipers (provided by the rider if you have conditions) to check the chain. Generally speaking, when the length of the chain exceeds 0.75% of the original factory, you should consider replacing it with a new chain.

Excessively worn brake pads (incoming pads) and discs will have a greatly reduced braking effect. If they are not replaced in time, they may even inadvertently cause the metal of the brake pad shell to directly contact the rim.
The edges of the rim (most road cars and mountain bikes that use V brake systems) will also become thinner after frequent friction with the brake pads. As a result, the lines that enhance the braking effect will be smoothed and the braking effect will be reduced. Secondly, the thinning of the edge of the rim will adversely affect the strength of the rim.
Generally speaking, when the wear remaining of the brake pads (coming pads) and disc brake discs is close to 2/3 of the original thickness, and the brake lines on the rim are almost worn out, replacement should be considered.

After a long period of use, the tires will be worn or cracked due to aging, which will undoubtedly reduce the grip of the tires and increase the possibility of punctures.
The same is true for the inner tube. If it is not replaced for a long time, it will easily cause a puncture due to aging.
According to the material and degree of wear of various tires, you should replace as much as possible every 2000-5000km. When replacing the tires, try to replace the inner tube at the same time. In addition, if the tire is repaired more than 2 times, please also replace it. Replace.

The pattern of the sleeve is easy to be smoothed in long-term use, which will undoubtedly increase the chance of hand slipping during violent movements such as rocking the car, which will bring danger. Moreover, many soft rubber grips will become sticky and uncomfortable to use in the long-term erosion of sweat and rain. Therefore, the grip is also a consumable that needs to be replaced regularly.
When these parts show signs of wear, aging, etc., please pay attention to them and check and replace them in time. If the bike becomes difficult to ride, it is a small matter. If there is a safety problem, it is really worth the loss!