A good bicycle brake disk is designed to withstand high heat without impairing the braking effect. Brake disks for bicycles come in different sizes. The larger the brake disk, the better the braking performance. Especially if you're riding in tougher conditions such as a lot of downhill or in bike parks. Larger brakes also give you better control over your braking. If your brake discs become warped or damaged, make sure to replace them as soon as possible to avoid the risk of brake failure.