The most popular brake for road and mountain bicycles is the caliper rim brake. The cyclist engages these brakes by pulling on levers which pull cables, forcing pads or shoes against the inner rim of the front or rear wheel. Caliper brakes are lightweight and inexpensive but they are not without problems. During wet weather it may take twice the distance to stop as it does in dry. The water acts a lubricant on the sides of the rims. During very long downhills the rims can heat up, even to the point of melting a hole in the tyre's inner tube!
When using caliper brakes, riders are advised to place gentle pressure on the brakes and modulate in a controlled fashion. Controlled modulation will help brakes perform better, particularly in wet weather, by removing some of the excess liquid from the rims. In addition, pumping the brakes will ensure the rider does not lock-up the brakes (when the tires stop spinning, the cyclist begins to lose control over the bicycle). Exploratorium Senior Scientist, Paul Doherty explained, "I balance the braking between the skidding the wheel on the ground and the skidding of the brake blocks. If I go into a skid so the wheels are spinning, I don't have control when I point the wheels of the bicycle. Just like the anti-lock brakes on a car, I want to keep that wheel rolling a little bit so I can steer and control the bicycle."

Balancing the braking between the front and rear tire is also important. Paul explained, "The most important things about stopping are that you want to stop quickly, in control, and not go over the handlebars. As I'm going along on the bicycle and I apply the brakes, my body has inertia and it still tends to go forward. That shifts my weight forward onto the front wheel. So, I do a lot of braking with the front wheel, but if I do too much braking with the front wheel, then I wind up going over the handlebars. So the idea of the braking the bicycle is to balance the braking between the front and the back to get the maximum braking."
 
U.S. Women's cross-country champion, Ruthie Matthes sees planning as a key to effective braking for many of the reasons that Paul cited. Ruthie told us, "We have the fortune in our racing to be able to pre-ride the courses so we can plan our braking." Ruthie continued to explain her technique for braking on sharp turns. "What I do when I'm racing, if I'm coming into a sharp corner I'll brake ahead of the corner, and as I'm going into the corner release the front brake and only use the rear brake."