Re: Ur-Q wheels/Tyres

[audidudi@delphi.com (Jeffrey J. Goggin)]

>Increased diameter may be a problem...but increased width isn't going to
>alter the suspension geometry much...especially only an inch! And if
>the  castor and camber settings are right I doubt tramlining would
>suddenly become a much bigger problem.

On the contrary ... altering track width by "only" an inch can/will
seriously change suspension geometry!  As you probably know, Audi designs
its cars to have a "negative roll radius" (this helps maintain stability
when you have a difference in traction from side-to-side or a flat tire) and
on a 4k, which is basically the same, this goes away after you increase
offset by 12-14mm ... the greater track width also affects your roll center
location, both statically and dynamically, as well as change the motion
ratio on your springs and struts, and lower the effective spring rate.  Mind
you, the differences will be small but they're differences nonetheless ...
merely swapping on larger wheels & tires isn't an automatic guarantee of
higher performance.

>Having said all that I think Jeffrey might be right..A nine inch
>rim/tyre probably wont fit at the front without flaring the fenders more
>so I,ll probably stick with 8 inches..:)

I was crawling around under mine this weekend and can confirm that if you
pick your offset carefully (and are willing/able to work around the changes
as outlined above), a 9" wheel with a 225/50-15 can be made to fit at the
back of the car.  Up front, it'll be tight but I *think* it can be made to
fit if you roll the fender lip under like at the rear, choose your offset
very carefully (it will be different than at the rear, making tire rotation
a PITA) and possibly limit steering travel to prevent the tire from hitting
the firewall when you're at full lock.  Of course, seeing that the car's
turning circle is already too large as it is, this would be a real PITA to
cope with ... I can't believe how often I find myself making 3-pt. turns
these days!

In any event, I'll be sticking with the OEM 8x15s for play days and 8x17s
for street use ... although I saw a set of 18s that I think would look
mahhvelous, just mahhvelous, on my 200q with a nice 225/35-18 tire.  Hmmm,
I'll have to give this some thought the next time I rob a bank, win the
lottery or receive an inheritance...   
        
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