hi Odie, I've just measured my spare Alpina 7x16 'E30' wheel. The hub-hole is ~57mm, & the offset is slightly more than 29mm. These guys fit the car "like a glove" and I've never had a rub. My suspension is rather stiff, and the tops of the wheel-arches are 24" (front) and 23-7/8" (rear) above the ground. Decent (heh!) amounts of 'negative camber' also help to keep the tops of the tires away from the wheel-arches, I've also tried to keep the f & r toe-in v. minimal, tho' this makes the car rather twitchy to road-conditions. It's been hard to find the best setup. But I've only ever used 205/45-R16 tires - my overall tire diameter is ~23-1/4". Your proposed 225/55-16 diameter will be ~25-3/4", so you'll need more clearance to the arch-heights, and perhaps a larger offset as well. IMO the 225/55-16 tire will be too wide & too tall for the car. Even w/ the 15" track-wheels, I only use a 205/50-R15 tire. The 225 width will give too much lateral grip, & the 55 sidewall will be too rubbery for precise turn-in. One prob I've had w/ both my +1 (track) & +2 (street) wheel/tire combinations is that the front is too grabby & the rear is too loose, when the tire-pressures are equal. So I generally run w/ 8psi (track) & 5psi (street) higher pressures in the front tires, which throws a bit more weight to the rear & makes the car much better-balanced. My point is, that making the change that you propose will *radically* change the handling abilities of your car. Having lots of grip, you'll be able to turn in at higher speeds, w/ much less 'push' than you're accustomed to. This'll be fine, so long as you keep the power on through the turn - but if you're ever (unexpectedly) req'd to lift throttle after a turn-in, you'll be traveling faster & will find the rear-end to be lots lighter than you're used to! This can be a prob in traffic, or in the rain.
15 wheels Tom, I just went through this exact excercise. I went with BMW 15" wheels from my local dealer, part number 36 11 1 179 066. The offset is correct and the bolt pattern is correct. They look almost exactly like the wheels you currently have on the car. Price after BMWCCA discount was around $220.00 per wheel, plus the center caps. You can also get some BBS wheels from Tirerack that are correct, but they are closer to $400.00 per copy. For the tires I went with Michelin Pilot Sport A/S 205/55. Yes it can be done for less money, but I plan to keep the car for a while and I really like the look of the original type wheel. Hope this helps. Almirinda
15" Euroweaves show up on eBay from time to time, but they aren't cheap. The Ronals are nice because they have locking center caps, but they aren't cheap either and are in limited supply. Another option are the Alpina Kopis that come in 15" and 17" IMO, 17" is a bit much for an E30 The 15" wheels are expensive, but they look nice. Google "Abrahams Motorsports" and check their web site. About $200.00 each. If they made them in 16", I would consider them, but if I go up to 15", I'll just go with another set of BBS Basketweaves or Ronals if I can find them. IMO, it's not worth spending $1000.00 for new wheels and tires for such a small size increase. I can think of better ways to spend that money on my car.
I agree that 17's are a little over the top, unless you're going straight to the track...kiss everyday ride quality goodbye. Just got my 15" Ronals today--they're beautiful! And not too hard on the wallet, either...grabbed 5 for about $990.
As an aside, I have a question for E30 Cabrio: did your car come with the rear headrests installed, or was that a DIY? My '87 doesn't happen to have any...
