It might happen that the brakes degrade and wear at different rates on the front and rear axles of your car. What is brake bias and what to do about it? This article dives into the whys and hows of this phenomenon.
Some drivers who have driven a car for a reasonable period of time may have noticed their front brakes get used up faster than the rear ones. There are various reasons behind such brake bias. Knowing what happens when the brakes are used will help you better understand how and why various car parts, especially brakes, wear out at the rate they do.
Front-rear brake bias and tyre wear
It is worth noting that the rate of your car’s brake wear is often also accompanied by a similar variance in the wear of front and rear car tyres.
Of course, there are numerous factors that can influence the condition of your tyres including the steering system, angle of camber and car suspension. However, the use of brakes directly affects tyres so don’t be surprised if you notice greater tyre wear in front than in the back.
Weight distribution
The concept of weight distribution is one of the most important aspects. We’ve mentioned this before, as the right tyre pressure is needed to support the optimal weight of a vehicle.
While driving, however, the conservation of momentum ensures that objects in motion stay the way they are. Because everything is moving forward, the weight isn’t completely pushing down on the vehicle.
Favouring rear brakes
There are, of course, a few cars that favour rear braking, in an effort to prevent the vehicle from dipping forward which happens when favouring the front brakes. For better brake balance, some manufacturers, e.g. BMW, often choose to apply more pressure on the rear brakes, or at least shorten the difference in pressure between the two axles.
In these instances, brake wear more evenly matches the ratio of pressure applied. Of course, even an equal split will not remove the pressure. Because of inertia and momentum, a shift in energy and weight occurs that will still press the vehicle down. So as long as you drive forward, then the inertia must also shift in this direction and, consequently, move onto the front wheels.
Brake wear in electric vehicles
Due to differences in design, braking works differently on electric vehicles. First of all, many EV models simply cut power from the motor itself, instead of just relying on the braking systems. More important than this, however, is that electric vehicles typically come with regenerative braking.
Regenerative braking is a more advanced method of braking compared to the traditional methods - known as friction braking - and is often seen in train designs, as well as motor sports such as Formula 1. Simply put, regenerative braking works by converting this kinetic energy into its useful alternative, often storing it for later or using it there and then. This removes the momentum that would otherwise cause excess pressure, reducing the strain on the brakes.
To make the most of this system, therefore capturing as much energy as possible, regenerative brakes are applied to all four wheels in most car designs. However, it must be admitted that regenerative braking is not a perfected technology and there are a few issues.
Notably, this effect decreases at slower speeds and the amount of braking offered is still low. That’s why electric cars also have friction braking as back-up. Similarly, friction braking is still needed for the likes of hand-braking, which actually keep the car physically still on slopes.
Whether you drive an electric vehicle or not, braking still has an influence on your brake pads, rotors and car tyres. Due to the nature of inertia, there will always be some shift of kinetic energy towards the front of the vehicle.
That said, one way to avoid this is to not brake at full speed, unless in emergencies. If you can, bring the car to a natural stop, or slow it down as much as possible in this manner. This way, there’s less energy stored up. Similarly, this is also a useful factor in improving your fuel economy.