Wheel size suggestions needed ASAP for my 1990 Audi Quattro Coupe....

[Grant Lenahan]

At 09:59 AM 8/25/00 -0700, ACAdelhoch wrote:
>I am ready to purchase 8x17 wheels for my Audi, but am not 100% certain of
>the offset needed. I think the factory offset for the 7x15 speedlines are
>37mm, but should I change the offset if I go with larger wheel width?

For most neutral handling, you want to maintain the *smae* offset, since 
that keeps the steering center where it was intended to be.

The fly in this logic is that some cars need to set the wheel further out 
to avoid rubbing a suspension component, but you didn't specify the car, so 
no one knows (except those who have your stable memorized :-))


>Please let me know what the correct offset should be on an 8x17 wheel.

See above.

>I am going with 215/45 r17 tires if using 8x17 wheels. Does this sound
>right? I used the aspect calculator and found this tire size to give the
>closest match to PLUS 2 upgrade.

geometry solves this one.
effective radius = wheel Radius + sidewall height
sidewall height = width * aspect ratio
circumference = 2*pi*r

Grant
==========================================
Grant Lenahan
glenahan at telcordia.com
gfl at erols.com
gfl at alum.MIT.edu