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Old 11-03-06, 02:56 AM   #67 (permalink)
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Russ Noble
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Re: Rear suspension bump steer

Quote:
Originally Posted by ross nicol
Chris
I can't go along with a lot of this. Just a couple of points I have a problem with. When you near a corner at the end of a straight and throw on the brakes the car's weight transfers to the front, the rear goes light and if brakes are biased too much to the rear they will lock up the rear wheels. In an extreme case you will spin.
Ross
If you turn in on the brakes as is often done in racing and have too much adjustment on the back you will get tail happy or spin LONG before the rears lock up! If the rears are locking you've got miles too much on the back. Under racing conditions you should wind front brakes on until they just start to lock at maximum straight line braking then back them off slightly. That way you are getting maximum braking effort and can go deeper into the corner under brakes. IMHO of course and every racer has different preferences.

If you are running too much rear brake and start screwing more onto the front you will find that the harder you brake the more weight transfer to the front you can get and hence more grip at the front meaning you can run even more front brake. Of course you can't get this same weight transfer in the wet which is why you have to back off the front brake adjustment on a wet or slippery track. This is why road cars generally are set up with too much rear brake so you don't get the fronts locking so easily in the wet. With dry bias a race car just won't slow down in the wet, the front wheels will lock and one is left with the impression of accelerating to one's impending doom!

Cheers
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° Scratchbuild. Spaceframe Mk1 wide body. Dry sumped, forged, 351W. LSD930. 10's & 14's.
Most parts now sourced. Body 80% done. Chassis, rollcage 95% finished. Suspension 70% built. Engine starting to build, and trans in a million pieces.

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Last edited by Russ Noble; 11-03-06 at 03:08 AM. Reason: clarification
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