A search here didn't turn up a clear answer to this question. I've got a chance to pick up an OEM 18" REAR M3 wheel with stock size 245/40 to use as a spare. Will it fit on the front without rubbing and get me home in a pinch?

No they don't fit the front without several degrees of negative camber.

FYI, the stock size tire is 255 not 245.

Thanks. I probably just pick up an M mobility kit, which didn't come with my car -- and hope for the best.

supposedly, the 330ci spare fits on the m... i don't have any experience with it, but maybe someone else can chime in on the real deal here

supposedly, the 330ci spare fits on the m... i don't have any experience with it, but maybe someone else can chime in on the real deal here

I've been researching this lately. The 330 ci spare probably fits. Not sure of the cost there. Or you can get an M3 donut spare, jack, and wrench from Bavauto or Leather Z for about $320 shipped. Or you can buy the necessary pieces and get the tire mounted yourself. Here are the individual prices:

Continental T125/80/R17 99 M CST 108.07 Tirerack, shipped
36-11-6-750-007 Black Wheel 70.75 Dealer
71-12-1-095-406 E46 jack 66.80 Dealer
71-121-179-953 Lug Nut Wrench 12.20 Dealer
Mounting tire, probably 15.00

So that's about 250 with the CCA discount, or twice the price of a mobility kit (which I don't have). For peace of mind I'm thinking now that I'll get the donut and just strap it down in the trunk.

Found these pics:

I carry this in addition to the mobility kit.

http://www.parmidge.com/pokie/plug_files/flat2.jpg

I know this is an old thread, but...

I just got back from an autocross with a guy who has 18" rear wheels on the front with 265s, stock camber. He said it was fine but 19s would not work. No signs of rubbing.

I'm running 18" rears all around on my E46 M3. I use these as my "All Season" I don't remember the size but can look if needed. I use 10mm spacers in the rear for looks. Great set up with Kumho All Seasons.

Fred

I had my shop pull one of my rears to see if it fit on the front with stock camber (1.0-1.2degrees or so), and it did *not* fit.

It rubbed against the front wheel well liner, and the top of the tire was pretty close to the upper lip (metal bodywork). If I had the tires on there with stock camber, and I hit a big bump, my fender would have probably been in trouble.

I could see it possibly fitting with enough camber to move the top of the tire completely under the wheel well, and perhaps pushing the front plastic bit forward a half" or so.

It's too bad, too, because I already have a single extra rear wheel.

BTW, this was stock suspension with 52k miles on it, and bridgestone RE050A PP's in the stock size 255/45. Possibly a slightly less tall tire would help with the rubbing on the plastic.

--Carey