From digest.v6.n243 Wed Feb 19 19:28:01 1997
Date: Wed, 19 Feb 1997 16:08:06 -0500 (EST)
Subject: M3 Tire/Wheel sizes (long version, sorry)
<<From: "J.T" <delmanjt_at_pacbell.net>
Date: Tue, 18 Feb 1997 22:59:01 -0800
Subject: biggest wheels and tires?!?
need help fast!!!!
What is the widest wheels and tires I can possibaly
put on the 1997 M3 without rolling the fenders.
*18x8.5+225/40 or 18x8.5+235/40 or 18x8.5+245/40*
Any information would be very appreciated.>>
I'm not sure what everybody's fascination is with 18" wheels, but it's your
money to spend. We only use and are familar with 17" applications, but
perhaps you can interpolate. We run 255/40-17's all around (despite the fact
that the Tire Rack swore they'd never fit). I know of people who use this
size tire with 17 x 9 rims, but since we only use 17 x 7.5/8.5 we can't tell
you exactly what offsets to use. You should be safe with the stock 41mm
offset in the rear based on the clearances of our application (we use 47 mm
with our 8.5's). One of the 17 x 9 companies is Forgeline. I'm sure that
they, or someone with them, can feed you info.
In the front, you're definitely going to have to space the wheels out through
offset to clear the front spring perch support, expect a minimum offset
change to 35 mm or slightly lower, unless you have your front spring perches
"squared off" in the tire area. This is a do-able modification for any
qualified shock fabrication shop (Truechoice). You can also convert to a
coil-over type arrangement to relieve the front spring perch clearance issue.
Send me a private e-mail with your fax # and we'll provide you with a small
sketch detailing the "squaring" modification.
You should also be aware that the 255/40 is taller than any of the M3's stock
tire sizes, so expect a slight drop in effective gear ratio. It won't be any
problem with the M3's torquey power curve, but will throw off the speedo
slightly. We just acquired a set of used 275/40-17 tires. It will be
extremely close, but they may just fit on the rear, but not likely. We'll
let you know.
Additionally, the stock M3 shocks are extremely(!) soft and are one of the
biggest hinderences to performance handling. If you think the M3 handles
well as-stock, you'll be amazed at the difference quality shocks can make.
But that opens up a whole can of worms that I'm not going to touch, because
what I'd recommend goes against the grain of BMW tradition and the only
available shocks are custom-made at this time. The aftermarket is close to
responding or just has, I hear.
Finally, what some of you guy's pay for brand name wheels is astounding.
There are several custom 3-piece wheel outfits that can set you up with
anything you need dimension-wise at a lower cost and lighter weight.
Granted, some of you aren't very technically inclined or informed, but most
of the wheel shops have experience with this car. Custom Wheel (John Purner
in Gainesville, FL; but heard he's moving to LA), Forgeline, and HRE are a
few. If you want a true ultra-light racing wheel without a centercap (but
you could probably fit a BMW emblem with a little machining) call David at
Monocoque Race Wheels in Santee, CA , (619) 448-2800. They can provide you
with a 3-piece 17" wheel that weighs less than 14 lbs. for under $500 ea; but
you'll have to give them your dimensional offset requirements and use extra
length non-stock lug bolts; the length you'll have to determine..
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