Tire size question

[Fnb2121]

I'm looking to put a set of Dinan wheels I have on my M3. Their 17x 8.5 (don’t remember the offset) currently they have a new set of 235-45-17 on them and those tires will be a little too big for the car. From what I gathered 235 40 17 will work for the rear and 215 40 17 for the front. But I was thinking about 225 40 17 for the front. Any help or opinions would greatly be appreciated

(wheels were on my E34 M5 and was using a spacer for the fronts)

[02fanatic]

You don't want to run 235/45's...too fat. 235/40/17 rear and 215/40/17 front is what I run with E39 Style 5 BBS's
(17"x8")...and I run a 3mm spacer on the front to clear the caliper anti-rattle clips. Great set-up...although many don't like odd tires front to rear....I "DO"! :-) Fills up the rear wheel wells great and handles fine for me. I don't drive it enough to worry about treadwear/tire rotation. If you drive your car daily you should probably rethink staggered tire sizes.

Offset is "key" to fitment...mine are ET20 as I recall. Stock 15" E30 M3 BBS wheels are ET30 I think, and the upsized EVO BBS 16" wheels are ET27. The 16" E28 M5 BBS are exactly the same as the EVO style wheels but the offset is 20mm. Anything under ET20 will really start to push your wheels outward, so fitment with larger tires may be close to rubbing depending on your setup.

8.5" wide rims should be ok, but you need to confirm the offset before selecting tires IMO...it should be on the wheel somewhere. 225/40/17's may be fine too, but they will be tighter up front depending on the suspension setup and wheel offset.

Hope this helps,

John

[Fnb2121]

This was extremely helpfull. I just sold my 91 m5 and got the m3 so I have to start to learn more about this car. I have a good understanding of it but it's all the small things I have to learn.

[ALPINE_M5]

225/40/17 would be nice if you can find them. Good luck with that. Won't be easy if not impossible. Some people have a set or two they are keeping. But after 7 years I wouldn't trust new old tires. Some have successfully run 235/40/17 all around. Many resort to the 215 and 235 combo setup due to easier availability. I personally hate the stretched look of a 215 on an 8.5 rim even on an 8 inch rim.

225/40/17 would solve many of our problems. Too bad they don't make them outside of some track tires.

[e30s50dan]

I run 235/40/17 all around with H&R race springs...no issues!

[4DAFUN]

I run Falken 452's in 245/35/17's up front on 9"x17" BBS RS's with 302 centers and 2" lips and 6.5" barrels, and 10mm spacers on stock brakes and callipers, with 245/40/17's on the back on 9.5"x17's, 302 centers, 2.5" lips, 6,5" barrels, no spacers, stock brakes and callipers, and with GC coilovers all around. Yup... 17" 245's all around. They rub just ever so slightly in the rear only, on really hard bumps. Rolled fenders would solve that but I don't want to risk ruining the paint. On the fronts, I had to add the 16mm Steering Rack limiters, in kit form from Turner Motorsport for $30 bucks, to avoid rubbing fore and aft on the inside of the front wheel wells. Works like a champ if your willing to give up a bit of turning radius for...looks.