Some thoughts:
If the rear end was hitting the bump stop in the "before cut"
condition, the out side tire load would be much greater than in the "after cut
condition", if the axle is now not hitting the stop. Once the chassis hits the
stop, that point becomes the roll center, give or take the flex of the bump
stop. In the "after cut" condition, the loading is more or less shared
between the rear tires as long as nothing touches. the tires will "corner
better", generating less slip angle and so "over steer" less.
By cutting the stops, and if the axle does not hit the stops, you have
effectively softened the roll resistance rate at the rear end, until something
hits that is. This should cause the car to "under steer" more.
Adding a stiffer rear anti-roll bar would be indicated. You need to get weight
off the outside front tire!
I would prefer to reprofile the bump stops for more progression that to cut
them. A cut "spring" is stiffer! So with a cut bump stop, you have nothing,
then bang! to stiff!. This abrupt transition could be the cause of the bad
behavior as well.
Regards
Calvin Grandy
Vermont
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> From: Daniel Neuman <dneuman@stars.sfsu.edu>
> To: datsun-roadsters@autox.team.net
> Subject: 'Pushing' the front end??
> Date: Friday, December 03, 1999 1:35 PM
>
> Hello All,
> I have a handleing question for everybody. Sense I redid the rear end
> and cut my rear bump stops to the 'improved street version' from Bob Sharpes
> manual I have noticed a change in how the car goes around corners.
> I have the comp springs and swaybar upfront with the stock bumpstops.
> Now when I go around corners it feels like the rear end is 'pushing'?? the
> front end of the car and causing the car to turn wider than before or in
> extreme cases the front tires lose traction and slide where before pulling
> the same stunt they would not??
> Is there a name for this condition?/ Oversteer?/ Understeer??? I am
> hoping that cutting down the front stops will fix this??
>
> Daniel 69 2000
> SF CA
> Its the big weekend.. old engine getting pulled out....
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