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Old 09-23-2012, 07:41 PM   #22 (permalink)
some_other_dave
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Quote:
Originally Posted by baldlobo View Post
you do know that proper braking technique can be learned for that; it's called threshold braking and steering...
I know about those, I've practiced them quite a lot. But you cannot brake hard and turn at the same time and stay in control. That's in part because when you hit the brakes, you are using the brakes on all four wheels at the same time. When you turn, the inside wheels are more lightly-loaded and will tend to lock up. Look at most race cars, especially those driven by less-experienced drivers, going into a corner. The inside-front wheel locks up.

Tires that slide on the pavement grip less than tires that are still rolling. Look up "static friction versus sliding friction". (Note those are incomplete models because tires do not use just friction to provide grip, but the models do partly apply.)

A modern ABS will monitor individual wheels and will back off the pressure on a wheel that starts to lock. So the inside wheel still slows you down because it is not sliding.

Threshold braking is the quickest way to bleed off speed in a straight line. ABS is the best if you are trying to slow down and turn the car at the same time. If you're trying for lap times, you are faster using threshold braking and then turning (using trail braking if your car really needs the help to turn in) and turning while not using the brakes at all. But if you're trying to avoid an obstacle, especially if you don't have a lot of training, "Stomp, Stay, and Steer" is the best way to go. You may not stop the car as early as you could in a straight line, but you slow it down and get around the obstacle.

Nemo has the facts in his post as well, but that does ignore turning.

-soD
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