[200q20v] V8 vs old S4 - tramming

[Linus Toy]

At 12:20 PM 3/2/2001 -0500, Glen Powell wrote:

>The follow-the-grooves problem (also know as 'tramming' I think) is mostly a
>function of tire and wheel width and tire profile. As width goes up and
>aspect-ratio goes down tramming becomes more and more of a problem. Two
>otherwise identical cars but with substantially different tire/wheel widths
>and tire aspect ratios will behave very differently. This is a trade-off
>manufactures have to make based on the target cusomer and his expectations.

I think the "problem" is more an issue of alignment.  On my '91 200q, I've 
had stock size 215/60-15, '92 S4 size 225/50-16, and my favorite, 
235/45-17.  The most significant tramlining I've experienced was with the 
15" wheels & tires, before I had the suspension realigned.  The alignment 
factor contributing most to this effect is camber--too much negative 
camber, to be exact.  While more negative camber helps the car "point" 
(turn-in) better or helps wider tires clear the fenders, the result is more 
tramlining effect.

Remember that on our cars with mac-strut fronts, lowering the car beyond a 
certain point often means you cannot reach alignment specs for camber.  One 
"trick" to minimize the tramlining effect of too much negative camber is to 
increase your toe-in.  This can't be too good for tire wear, though.

--Linus
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*  Linus Toy                      Insanity is doing the same thing   *
*  Mercer Island, WA              you've always done and expecting   *
*  linust at mindspring.com          different results                  *
*                                      - Roger Milliken              *
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