[s-cars] Tires/Wheels

[Ray Tomlinson]

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Trevor,

The Toyo tire rep may have agreed with you that you need a stiffer sidewall
tire, a tire stiffer than the Sumitomo's, but you may be disappointed to
learn that simply going Plus 2 on the wheel size will not necessarily yield
a stiffer sidewall.  In fact, you may wish to discuss actual tire sidewall
stiffness with each manufacturer for a given size - example:  The sidewalls
on a 205/45/16 Dunlop 8000 are less stiff than on a 205/50/15.  You may find
that the answer lies not in decreasing aspect ratios, but in rim width and
tire choice.

Increasing swaybar stiffness, spring rate and dampeners may only exacerbate
sidewall flex.  If the suspension won't yield, your strut towers, wheels and
tires will.

Ray Tomlinson
Boston

-----Original Message-----
From: s-car-list-admin at audifans.com
[mailto:s-car-list-admin at audifans.com]On Behalf Of Trevor Frank
Sent: Wednesday, March 19, 2003 11:06 AM
To: TM; CyberPoet; s-car-list at audifans.com
Subject: RE: [s-cars] Tires/Wheels



On the Track I had real problems running 255x40x17's.  Way to much side
wall roll / flex.  This is why I have gone to 18's.  At 2.2deg neg
camber running Sumitomo HRZ2's with V8 springs in the front and koni
sports on full hard and adjustable spring perches in the rear with 400lb
I was still rolling the side wall to the point I was taking off the
lettering.  This was all while I was coming off of the track with the
tires at over 50psi.  I had the local toyo tire rep come and look at my
set up and he came to the same conclusion I did.  Stiffer front springs,
stiffer front and rear sway bar, and definetly stiffer side walls.  I
may have been able to get from here to there with stiffer springs, or
just a stiffer sway bar, or wider rims, but I figured either way I need
new rims and 18's are going to be stiffer than 17's.  For the rim's I
was looking at the difference in the tire and rim combo was about 3lb a
corner.  But I reduced it from my last set up 8lb a corner, that and the
Magnesium uprights should help out a bunch for unsprung weight.

-----Original Message-----
From: TM [mailto:t44tq at mindspring.com]
Sent: Tuesday, March 18, 2003 5:16 PM
To: 'CyberPoet'; s-car-list at audifans.com
Subject: RE: [s-cars] Tires/Wheels


Marc-
There have been quite a few discussions about wheel weight
and unsprung weight and how it affects handling.

Unfortunately, it is quite expensive to get a lightweight wheel in a
larger size.

As for the bigger is better thing, I've experienced significant
improvements in ultimate grip by going to a larger tire/wheel
combination. I'm much happier with my car shod with 255/40R17 rather
than the stock 215/60R15 and I've noticed a significant improvement when
going from my old 225/45R17 to 255/40R17.

I've also noticed significant degradation in ride quality when running
my winter 28lb. Avus wheels vs. my summer 22lb. wheels.

IMHO, you have very little to gain by going to a 18" wheel, although
unfortunately, there are very few aftermarket 16 and 17" wheels in a
5x112 bolt pattern and significantly wider than stock and currently
produced.

I think a 245/45R16 on a 16x8.5 or 16x9 wheel would do just as well as a
17x8.5 or 17x9 with a 255/40R17, but that is pure speculation on my
behalf.

For my next set of wheels I am looking to go to a 17x8.5 or 17x9 with a
target of sub-19lb. if possible.

Taka

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