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Old 07-27-2012, 12:23 PM   #40
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Originally Posted by BetaDnB View Post
I hate to bring this back up, but I tried something. If you pull the ebrake the rear of the car squats. What would make this any different than using the hydraulic rear brakes only?

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Good question. That's the torque from the rear brakes being trasmitted up through the suspension and frame. The parking brake doesn't exert enough torque to decelerate the car very rapidly, so the weight shift of the car is minimal and doesn't overcome the apparent effect of the brake torque on the suspension/frame.

Another way of putting it, if you were driving forward at 50 mph, and you made a panic stop with the pedal, those rear brakes will "pull" the rear of the car down slightly, but you've shifted so much weight off the back end of the car that the rear springs "push" the rear end up even more than the pull from the rear brakes, and the net effect is that the rear end will rise.

As proof, try driving backwards (slowly and carefully ) and then yank the parking brake. The rear of the car will actually lift up because the rear brake torque is in the opposite direction versus when driving forward.

And if you want to go crazy, build up some speed in reverse and stomp the pedal--the rear end will drop, as expected.

You could make the car nosedive driving forward with rear brakes if there were a way to activate only the rear hydraulics, ori if you had a ridiculously powerful parking brake.
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