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Date: Wed, 25 Nov 1998 23:42:39 +1100
From: Byron Forbes <hosh@ar.com.au>
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Subject: Re: BUMP RUBBERS by Steve Blank -------------
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Recently, I changed my setup at Spa from a ride height of 1 to 1.25 and the difference
was dramatic as you travelled down the start/finish straight ie the car was bouncing much
less and was far more controlable at 1.25. This tends to indicate to me that the car is
riding on the bump rubbers at the minimum ride height. This is also suggested by Doug
Arnao in his interview with Randy Magruder at Digisports. However, as you all probably
know, it is possible to have ride height set to 1.00 and bump rubbers to 2.50 so once
again I am at a loss. I might go and see if I can see a difference in handling between
bumps of 1.00 and 2.50 at very low ride heights. Or maybe I'll just go and read the manual
right thru this time :)

SteveBlank wrote:
> 
> >How exactly does one determine how much suspension
> >travel is available before hitting the bump rubbers?
> 
> Good question.  Not an easy one to answer, though.  GPL (the Lotus, anyway) has
> at least 5 inches of positive wheel (not shock) travel (see my post on low
> riding and bump rubbing).  Even at max ride height and spring rate , there are
> a few inches of sag, or negative travel  left in the suspension. Go flying over
> a hill and you'll see it extend. At ride heights below 5 inches, you have to
> either stiffen spring rates and/or fit longer bump rubbers (supplemental rubber
> springs, actually - they're not "stops") to keep from bottoming.  How much of
> each depends on the track and your preferences as to ride/handling qualities.
> Since we don't know the suspension geometry, we don't know how much shock shaft
> we're working with; thus the quandry.  I'd say if you run the full 2.5 inches
> of bump rubbers, they'll come into play pretty early, but gradually so,  in the
> travel, allowing you to run softer springs for a more progressive rate.
> 
> Opinions, anyone?
> 
> Steve B.

-- 
 Byron Forbes
 Captain of Team Lightning Bolt

 http://members.tripod.com/~HOSHUMUNGUS


    and

 http://www.frontiernet.net/~godsoe/bolt/home.htm
