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How Brake Calipers Work


Motorcycle Brake Calipers
Motorcycle brake calipers may be smaller than the brake calipers on other vehicles, but they provide plenty of stopping power for the relatively lightweight bikes.
Motorcycle brake calipers may be smaller than the brake calipers on other vehicles, but they provide plenty of stopping power for the relatively lightweight bikes.
Peter Finnie/iStockphoto

Motorcycles are smaller than automobiles and therefore need less stopping power. Nonetheless, the ability to slow down or stop is in some ways even more important on a motorcycle than in other vehicles. How so, you may ask? Well, since the driver is largely unprotected, even a small fender-bender can be potentially fatal. Accident avoidance is critical when you're riding a motorcycle. But what kind of brake calipers does a motorcycle need?

­The answer is relatively simple -- small and light. Unlike the larger calipers used on some cars and trucks, motorcycle brake calipers must be kept small to avoid weighing down the bike and getting in the way of the rider. Motorcycle brake calipers are commonly made of lightweight materials such as aluminum, which also has the

added advantage of being rustproof. Some motorcycles are bigger and more powerful than others; obviously, those bikes need more stopping power. Many smaller,

less-powerful bikes still use drum brakes, but most of the larger bikes now have disc brakes -- especially on the front wheel. To increase the stopping power, calipers on more powerful motorcycles typically have multiple pistons. Some have two or even four pistons, while others may have as many as twelve pistons in a single caliper. With their relatively light weight, most motorcycles actually have more stopping power than is absolutely necessary -- but like we mentioned earlier, that's not a bad idea when you're riding on a fast, unprotected vehicle.

On a motorcycle, the front caliper attaches to the fork -- the metal assembly that holds the front wheels and suspension in place and supports the handlebars. Until recently, the calipers have been attached to the forks using bolts that run at right angles to the rotor. In recent years, with the growing popularity of radial disc brakes (a technology that began on racing bikes), calipers have been attached farther away from the fork using bolts that run parallel to the rotor's surface. These radially mounted calipers reduce the amount of vibration in the fork caused by traditionally mounted calipers.

Because they tend to be more exposed than automobile calipers -- and because the caliper is probably the most conspicuous of all of the motorcycle brake parts -- the appearance of a motorcycle caliper can be important to many riders. In fact, brake caliper paints are available from auto stores and can be used to customize your motorcycle calipers. Of course, the same paint can also be used on automobile calipers, too. Experts advise against putting chrome on the calipers, though. As attractive as it may be, the chrome can cause the caliper to retain heat, which will produce unwanted brake fade.

Next, let's find out what characteristics make for a good truck brake caliper.

 


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