June 16, 2003. Copyright, 2003, Graphic News. All rights reserved

Getting the best from Formula 1 brakes
By Joanna Griffin

LONDON, June 16, Graphic News:  Anyone can step on the accelerator, but itÕs knowing when to slam on the brakes that makes the difference in Formula 1. In racing, good braking is as vital as a powerful engine to get the fastest lap times, and then there is the safety aspect. Of course, road traffic doesnÕt test a carÕs ability to stop in quite the same way, but the systems have similarities Š and both need practice.

In Formula 1 the quest is to simulate ABS braking systems, where an onboard computer calculates the rotational speed of each wheel to prevent it locking under braking. Formula 1Õs governing body, the FIA, rules out ABS, which would result in minimum stopping time for the given mechanical grip, so technologists must find other ways to get the same results.

The disc brakes fitted to racing cars are similar to those on passenger cars, but there are key differences. The FIA requires drivers to use aluminium brake callipers, and a maximum of six pistons and two brake pads per wheel. Since the early 1990s brake discs and pads have been made of a high-tech composite carbon lighter than the steel used in brakes in ordinary cars.

Nothing strains brakes like Formula 1, where a car may slow by up to 200kp/h in a few seconds and a driver may be subject to deceleration forces equivalent to several times his own body weight. A key concern is overheating Š brake discs are heated up to 1,000 degrees celsius within a second Š and most teams now use specially drilled brake discs that allow cool air to pass through. But there is more to good braking than high-tech, durable brakes.

Tyres play a part, too. Since 1998 the FIA has required drivers to use grooved tyres, which provide 20 per cent less in bearing surface than previously used slicks. By reducing the grip the FIA hoped to reduce cornering speeds and lengthen braking distances, but manufacturers Bridgestone and Michelin got round this with new rubber compounds. Their softer tyres provide better grip and therefore higher speeds, but they are also quickest to wear out.

Formula 1 drivers can also enhance their braking performance by adjusting their wing set-up. Steeply set wings provide more aerodynamic downforce, thereby increasing cornering speeds and shortening braking distance. Here, the stronger engines have the edge because their cars are still faster on straight stretches, where a steeper wing setting might decrease speed.

In Formula 1, the brakes must be changed after every race. But on ordinary passenger cars, too, brake pads and discs can wear out and need to be checked to see whether they should be replaced. Similarly, brake fluid may need replacing if its boiling point has been lowered through absorbing water from the air since this can cause a breakdown in the system. 

However fast a car is moving, good braking technique is vital for safety. Only rarely does road traffic require a full slam on the brakes, but motorists still need to know how to stop in an emergency situation. In cars without ABS, for example, the steering can go if the front wheels lock. And it might surprise some to know that drivers need to press harder on the brakes in cars with ABS than in those without it. They also need to keep up the pressure if the system is to work.
/ENDS