Wheels

["Lew Becker" <subecker@xxxxxxxxxxxxx>]

Chris G asked: " mmmmmh! This brings in options when I get around to new
wheels one day. So lets have feedback from those who have gone to the same
size wheel all around on 96+ models. Benefits and drawbacks please."

The following is based on personal experience with a 97 M3/2, with Dinan
Stage 3 suspension (Dinan's springs, custom valved Bilstein struts and
shocks, sway bars, and front camber enhancement -- swapped strut plates, for
negative camber similar to camber plates).

I'm running the 8.5 M Double Spoke 2 wheels with Yoko 245/40 AVS S1's all
around.  I have no fitment problems, whatsoever -- the offset on the
factory's 8.5's does not require any spacers, fender lip rolling, etc. for
clearance (and, I expect that all the factory 8.5 M3 wheels -- Double Spoke
2's, Contours, and forged -- have the same offset).  In contrast, the ever
popular  8.5 Fikses require fender lip rolling at the rear, especially with
a lowered suspension (even slightly lowered -- eg., 4 adults, with stock
suspension pieces); even Dinan's 8.5 custom wheels require spacers front and
rear.  I note, however, that there is not much clearance between the inside
tip edges of my front wheels and the struts -- this condition is exacerbated
by the negative camber I'm running, which places the tops of the front
wheels closer to the struts.

Aesthetically, the 8.5's all around look lots better than stock -- they fill
out the fenders better; and the car has a subtle, but noticeable, more
aggressive stance.  Perhaps best of all, however, is the ability to rotate
tires (so fronts and rears wear evenly), and replace 4 all at a time.  The
rear tires on the E36 M3's wear considerably faster than the fronts.  When
mine went, I was unable to locate 2 new 245/40 Pilots, and instead got the
AVS S1's (which I do not especially recommend).  Mixing tires front and rear
upset the car's balance (one of the M3's strong points); other Digesters
have experienced the same when replacing the rear Pilots with Bridgestone
SO2's.  I opted to get 2 more 8.5's for the front so I could run the same
size all around (and rotate) when it was time to replace my front Pilots,
largely for this reason.

The E36 M3's understeer.  Running the wider wheels/tires up front will
reduce this.  I was running the stock staggered tires (with my Dinan
suspension) at the same tire pressure all around -- 36 psi.  My Dinan
suspension was set up for neutral/slight understeer (lots less than stock).
However, when cornering, I felt the car had too much body lean (albeit less
than stock) -- the Dinan suspension is not overly stiff (although a bit
stiffer than stock) nor much lower (again, a bit lower than stock); and, as
a result retains some body lean (which I suspect the stiffer/lower sprung
cars do not -- eg., H&R's with Bilstein Sports and RD bars, another Digest
favorite; which all agree is stiff, and some have removed because the setup
is too stiff and/or low).

The Dinan sway bars are adjustable.  Although I could dial out some body
lean by stiffening up the front bar (the rear was already set at its
stiffest setting), I would have also dialed in more understeer (which I did
not want under any circumstances).  So, when I added the wider wheels/tires
up front, I also stiffened the front bar in the hope that the reduction in
understeer from the wheels/tires would offset the increase in understeer
from stiffening the front bar.  It didn't work as well as I would have
liked -- body lean was noticeably reduced (to an acceptable level); but,
there was still more understeer than I liked.  So, I started playing with
tire pressures.

With the stock staggered wheels/tires and the initial suspension setup,
Dinan recommended running the front tires 2 psi higher than the rears.  I
tried this setup with the 8.5's all around, and still had a bit more
understeer than I liked.  So, I went to a 4 psi differential (38 psi front,
34 psi rear).  This setup worked well -- slight understeer on fast sweepers
(the fronts tires start complaining just a very little bit before the rears,
so I'm unlikely to lose the back end first absent some significant brain
fade/red cloud); and, I can kick out the back end on tighter corners pretty
easily (so easily the first time, that I considered dropping down to a 3 psi
differential).  Initially, I ran 38/34 psi front/rear, but I've since run
37/34 and am happy with it (although I may go back to the 38/34 setup this
spring/summer (when dry roads are the norm).  (BTW, if you haven't since
outside temps have dropped, you should check your tire pressures -- lower
ambient temps result in lower tire pressures, even without any leak or other
problem; in SF Bay Area, the colder weather resulted in ~3 psi  drop all
around).

FWIW, if I didn't already have two 8.5 M Double Spoke 2's (stock M3 "sport"
wheels), I would have run BMW 8.5 forged alloys all around.  I have not
regretted for a minute upgrading the front wheels/tires; and, would do so
again knowing all that I do, without hesitation.  I sold my front 7.5's
(through the Digest) to defray the upgrade to 8.5's all around.  If you
can't find some good used 8.5's, you should be able to get new ones at 25%
off BMW's suggested retail price.

Lew Becker

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