Of all the skills that a race car driver must master to go quickly around a road or street course, none is more complex or more critical than braking. In fact, braking is important enough and complicated enough to discuss that I plan to devote two of these articles to it, and I'll do a third article, later in the series, on the unique characteristics of antilock braking systems (ABS).

No racing skill is harder to execute perfectly or to learn than is slowing a race car at the limits of its braking performance. It occurs dozens of times each lap on the race track. Slow down too much, too slowly or too soon and you've lost critical lap time; slow down too little, too quickly or too late and you've lost your race car or more.

There are three factors that make braking so complex. First, virtually all braking during a race is done at the absolute limits of the car's performance -- at the limit of the brakes' ability to convert the car's kinetic energy into thermal energy and/or at the limit of the tires' ability to adhere to the track surface. Second, the car's braking characteristics are never the same for two stops in a row. Third, the act of braking induces changes in the race car's posture, its weight distribution and its handling characteristics, all of which make braking more difficult and complicated.

Because race braking is done "at the edge," race car drivers have plenty of opportunity to experience and to practice braking for maximum performance. The everyday driver rarely experiences braking at the limits. When we do, it's an emergency, and one for which too few of us are prepared. I'd like to see every driver have the chance to practice braking at least twice a year, coming to a full stop as fast as possible, without skidding, from 30, 45 and 60 miles per hour. If all of us knew exactly what that feels like and how much time and distance it takes, the streets and highways would be safer places to drive.

There's a television commercial on these days that says something to the effect that your brakes stop your wheels; your tires stop your car. That's actually a profound statement, for all that it's technically flawed. Tire characteristics such as pressure and tread depth have a direct impact on a car's ability to stop. Race cars are checked for tire pressure and condition dozens of times during a race or practice session. Do you know the ideal tire pressure for your passenger car? Do you know how to measure it? What's the tire pressure of your car right this very minute? If you can't answer these three questions, you are in increased danger of not stopping in time when you need to. Tire pressures should be checked every time you put gas in your tank, and you should take a conscious look at the tread on your tires every time you get into your car.

When you step on your car's brakes, whether gently or firmly, some of your car's weight transfers from the rear of the car to the front. You experience this in the front end's dipping down. Your front brakes and tires experience it by having to do more of the work of slowing. That's why your front brakes are probably larger than your rear brakes and why they will probably need maintenance before the rear ones will. Weight transfer happens as a result of the laws of physics and your car is designed to accommodate it.

However, if you "grenade" your brakes -- if you stomp on them -- it is possible, even likely, that your more powerful front brakes will lock before that weight transfer occurs. Your tires will be skidding well before your brakes have dissipated any energy, and most of your braking effectiveness will be lost. The race car driver learns, and every passenger car driver should learn, to squeeze the brakes on (rapidly) rather than to stamp or slam them on, and to maintain pedal pressure right at the brakes' limits. The panicky "Oh no....STOMP!" stop has no place on a track and no place on the streets or highways; when it occurs either place it's likely as a prelude to a crash.

Copyright © 1998 by Tim Moser of Silhouette Racing. All rights reserved.