The wheels on the racecar are supposed to go round and round all the way down the track, but how can you make them do it better without adding power? One way to improve the rotation is to make sure the front wheel bearings are set in the most optimal manner possible. Having wheel bearings that are free helps to eliminate ET-robbing drag and heat, so your car can reach its maximum potential on each pass.
By reducing the heat and drag produced by bearings that aren’t set correctly, a racer can eliminate poor handling, braking issues, and cut down on the parts wear. Avoiding wear caused by excess drag from tight bearings will let your rotor move freer inside the caliper and eliminate a drag brake effect while making your car safer too.
Randy Cotteleer from The Brake Man explains what this diagram from Timken means when you’re looking at setting front wheel bearings.
“The area that concerns us is the dark gray curve at the bottom of the chart. This curve represents the expected life of a bearing for a given preload spec. Following the curve, we see that a bearing will live the longest with a preload of .001-.002. While this is interesting, it has little to do with racecars where minimizing drag with minimal sacrifice to life is desirable. Looking at the chart, we see that there is a minimal change in life between +.002 (end play) and -.002 (preload), however, there is a significant difference in drag, and a significant difference in stiffness, which depending on your application, should be equally important.”
Cotteleer talks about what he has found that works best for straight line performance when it comes to wheel bearing settings.
“No matter the distance you’re racing, optimizing a car for straight line performance involves reducing drag wherever possible. For these applications where the car isn’t used on the street, we recommend a running end play of .000 to .001, this minimizes drag while keeping unwanted axial movement to a minimum.”
Cotteleer goes on to explain what you should look at if your car is seeing any type of street duty.
“As soon as we start adding corners to the mix, we have to take advantage of the stiffness that bearing preload will give us even though we pay a small price in drag. If the bearing/spindle/hub assembly isn’t sufficiently stiff, the unwanted movement will manifest itself in toe and camber compliance making the car less consistent and more difficult to adjust. Therefore, we will target .001-.002 of preload for street cars and those that race around corners.”
As you can see there’s some nice hidden horsepower and a way to improve how your car behaves at the track in setting your front wheel bearings. Make sure to check out The Brake Man’s website to get more tips on how to bring your car to a stop in a hurry!