Bump steer?

PostPost by: chrishewett » Wed Oct 24, 2007 4:35 pm

Coming back from norfolk on monday I noticed that the rear jumped about quite alarmingly when I hit a bump in the road at high speed. The car was well loaded up in the boot, rear seats and my son in the passenger seat.
Is this " bump steer"?
I havn't noticed this effect now the car is unloaded. I checked the obvious things underneath and could see nothing obviously loose.
Is this a normal effect?
Chris
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PostPost by: peterako » Wed Oct 24, 2007 4:58 pm

Possible shot rear shocks???

Peter, 1973 +2S 130/5...with possibly shot rear shocks....
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PostPost by: stuartgb100 » Wed Oct 24, 2007 5:08 pm

Rear bump stops .... ?

Regards,

Stuart
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PostPost by: 264889socal » Fri Oct 26, 2007 12:58 am

Chris,

Sounds like the rear spring/shocks bottomed out. When this happens, an abrupt change of direction can occur. On the front, I will manifest itself as understeer or "push" as the NASCAR boys call it. Bottoming out in the rear, will cause the rear to "step out" or get loose.

Rob Walker
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PostPost by: Tintin » Sat Nov 10, 2007 8:51 pm

chrishewett wrote:Coming back from norfolk on monday I noticed that the rear jumped about quite alarmingly when I hit a bump in the road at high speed. The car was well loaded up in the boot, rear seats and my son in the passenger seat.
Is this " bump steer"?


Bump steer usually refers to an effect which occurs if the track rod joints aren't positioned in the correct locations. It means that there is unwanted steering movements over suspension travel. Usually if the chassis designer understood what he was doing bump steer will be quite minimal over the full operational range of the suspension - and that should include "well loaded up".

If you really care about bumb steer you would need to measure the toe-in on the wheels for several different suspension settings aka ride heights.

In your case I would too assume a bottoming-out effect.


Tim
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1964 Norton Atlas - 1974 Lotus 130/5
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finest british craftsmenship
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