What are the hairs on new tires really?

Written by hana

Why do your tires have rubber bristles?

car tire

Car tire – Source: spm

Many drivers are probably aware that tires have special markings in the grooves that provide a host of useful information. Including tread depth and date of manufacture or production. Thus, all the items mentioned on the side help to have a better view of the expiry date of the material.

However, you may have already wondered what those bristles covering your tires are for. No, it is not a manufacturing defect or sign of wear. On the contrary, according to specialists, it is precisely these hairs on the tire tread that are evidence that it is new and in good condition. In fact, their role is strongly linked to ventilation. It is also called “ventilation sputum”.

Rest assured, these bristles do not in any way disturb the operation of the wheel and do not pose any danger. Over time and miles traveled, it starts to wear off before disappearing completely. Moreover, even if few people notice it, almost all tires (whether bicycle tires or agricultural machinery) have similar felt.

How exactly are these filaments formed?

Car tire felt

Car tire felt – Source: spm

Frames are manufactured using molds that give them the desired shape. The process is done by injecting liquid rubber and air pressure that keeps it in each corner of these moulds. In other words, between heat and pressure, the rubber expands to fill the mold. Specifically, in order to allow the rubber to fill effectively, it was necessary to create evacuation or ventilation holes to allow air pockets to escape.

Because, when heat and pressure are applied, there is a risk of air bubbles forming between the mold and the rubber. If you keep anything inside, the frame may be defective. This is why ventilation holes are necessary to evacuate them properly. Also, during this deflating process, excess rubber also exits through these channels: hence those hairs that remain stuck to the tire. This indicates that the wheel is still new!

How long do they last on the tires?

It all depends on the type of frame and its use. Tires with softer tread shed those hairs faster. Likewise, they will wear out faster when it comes to high-pressure tires, such as those intended for race track or rain tires (with tread). As for slick tires, without a tread, they are made using a different technology and instead of bristles, they have a thin strip on the sidewall.

In general, in the case of normal car tires, these hairs can be seen even after 3,000 or 4,000 kilometers have been traveled.

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