In most cars, including street cars, pressing on the brake pedal applies a little more force to the front brakes than the rear. This is designed to take advantage of the fact that under braking, weight transfers to the front of the car. With lots of weight on the front tires, the brakes can be applied very hard without completely stopping the wheels from rotating. At the same time, the rear of the car tends to get lighter so the rear brakes must be engaged less strongly than the fronts to avoid locking the wheels and possibly losing control. In a racecar, brake bias is adjustable by the driver to compensate for changing conditions.