Don't run high speed immediately after changing the brake pads

The surface of any object cannot be flat, and the same is true for discs and tablets. Generally speaking, only when the contact area between the two reaches more than 75%, can the braking force be large enough and the braking effect can be fully exerted; if the contact area between the two is too small, the friction between the two will be compared during braking. If it is small, the braking force will be insufficient, and the braking distance of the car will be extended. In general disc brake systems, close to 100% contact can be achieved between the pad and the disc, but for drum brake systems, 80% of the contact surface is quite good.

For the old disc and the brake disc, the surface impressions between the two are consistent with each other because they are in contact for a long time and rub against each other. For example, if there is a groove on the brake disc, there will be a bulge in the corresponding position of the disc; if the brake disc is eccentrically worn for some reason, it will also be eccentrically worn. The two are almost 100% in contact, ensuring that sufficient braking force can be generated when braking.

But after replacing it with a new one, the situation is different. The new surface is relatively flat, while the old brake disc surface may be uneven. After assembly, the contact area between the two may be small, and some may not even reach 50%. In this way, when braking, because the contact area is too small, sufficient braking force cannot be generated, and the braking distance will be extended, and there is even a danger of being unable to stop the vehicle. After some people change, the brakes are not as good as before. That’s why (many people don’t understand this reason and think it’s not good, but it’s not the case)

Some people say that my films and discs are new, so this should be fine. No, even if it is a new disc and film, due to machining errors, the two will not be in 100% contact. In addition, there is an oxide film on the surface of the new disc and film, which will reduce the friction coefficient of the two. Motivation will also drop. Therefore, after the new car leaves the factory, the brake system will be run-in in the instruction manual. Generally speaking, it is said that the film and the disc can achieve the ideal run-in and combination state after 500 kilometers. Please drive carefully within this mileage.

So, what should we do after replacing the new brake pads?

One way is to drive cautiously within the first five hundred kilometers and keep a sufficient distance from the vehicle ahead when braking. In the driving, the brakes are often consciously stepped on, so that the film and the disc often contact and rub, so that the surface impressions of the two are matched as soon as possible, and the contact surface is larger.

Another method is to find an open area, increase the speed of the car to more than 100 kilometers, and then apply the brakes with a moderate force to slow the car until it stops. Repeat this many times until the braking distance meets the requirements. In this process, you must be careful not to overheat the brake system. If it is overheated, stop and rest, and continue to run in after the brake system has completely cooled down. This method is suitable for long-distance running vehicles in a hurry, and can achieve the purpose of fast running-in.