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[///M Pow3r]

After lots and lots and lots of thought I've settled on these wheel/tire sizes for HRE P40s and PS2s, please tell me what you think. Specs are courtesy of Tire Rack. Also, I bought H&R springs but after much internal debate I ultimately decided not to put them on. Maybe eventually I'll do a coilover but I'm keeping the suspension stock otherwise. As a note, I'm going to go the supercharger route (but probably not for another year or two I think) so I wanted big rears to accomodate the power. I'm not a baller so when I do get wheels I want them to be sized accordingly. I probably won't get wheels until the fall, but maybe we can get a discussion going since I know I'm not the only one wondering about wheel sizes for 600+ whp M3s.

Stock:
Front - 8.5 x 19, 245/35/19, 25.8" diameter, 807 revs/mile, 47.5 lbs
Rear - 9.5 x 19, 265/35/19, 26.3" diameter, 790 revs/mile, 50.5 lbs

My Plan:
Front - 9.5 x 19, 275/30/19, 25.6" diameter, 814 revs/mile, 50ish lbs
Rear - 11 x 19, 305/30/19, 26.3" diameter, 788 revs/mile, 55ish lbs

First of all, I'm not sure if 9.5" front and 11" rear will fit. Some people think it will, some say 9.0" front and 10.5" rear is the biggest you can go. Can anyone confirm this? Also, I'm not sure what offsets to go with.

This setup is very very close to stock in terms of diameter so rubbing/speedometer issues are practically void. Even lowered, with these sizes I don't think there will be rubbing. My main concern is are these tires too big? Am I going to get understeer? The difference in width increase is 0.5" (+1" front and +1.5" rear) so that shouldn't be too bad right? I haven't tracked my car yet but I do enjoy some (or much ^__^) spirited driving so I don't want to mess up the handling, which is another reason I'm not going to just arbitrarily lower the car.

I don't have exact weights on the P40s in that size so it's a rough estimate. I've read discussions on rotational mass which is one of the reasons I'm sticking with 19s (and the tire sizes for 20s aren't as close to stock in these widths). I really love the Advan F7s but I feel like they're too small (9" front, 10" rear).

Thoughts?

[FrankieP]

9.5" is too wide for the front. 9" max unless you want to rub when turning.

[///M Pow3r]

[swamp2]

Originally Posted by Frank@CEC

9.5" is too wide for the front. 9" max unless you want to rub when turning.

What is a good offset to use with a 9" wide front wheel to have the same appearance as a stock wheel with a 15mm spacer? Can you show me the "calculation" for this as well?

[Big Windy]

Originally Posted by swamp2

What is a good offset to use with a 9" wide front wheel to have the same appearance as a stock wheel with a 15mm spacer? Can you show me the "calculation" for this as well?

swamp, stock offset up front is ET +29. With 15mm spacer, the offset becomes +14. If you wanted to keep the outer edge appearance, you'd want to go with an offset of ET +20. By doing this, though, you sacrifice 12mm of inner clearance.

Why calculate when a webpage will do it for you???

http://www.1010tires.com/WheelOffsetCalculator.asp

Throw in 8.5 and 14 up top, and then put 9 inches in the bottom and mess around with the offset until you get what you want for inner and outer position below.

[Radiation Joe]

Originally Posted by Frank@CEC

9.5" is too wide for the front. 9" max unless you want to rub when turning.

How can you say this? Even the e46 easily fit 18 x 9.5 in the front with 265/35-18 PSCs. I run 18 x 9.5 in the front on my e90 M3 and it doesn't rub with 18x9.5 et23 and 265/40-18 (stock rears). I don't even have the optimum offset for clearance. An 18x9.5 with et28 - et30 will clear even on the inside.

[lucid]

Originally Posted by Frank@CEC

9.5" is too wide for the front. 9" max unless you want to rub when turning.

As RJ said above, this seems off. I've seen the TMS car running a 10" square setup at the track with 275s. I'm pretty sure the fenders were stock.

Front & Rear: 18x10" 5x120mm - 275/35/18

http://www.turnermotorsport.com/html...L-TIRE-PACKAGE

They are also selling the following setup for street use:

Front: 20x9.5" 5x120mm - 27mm offset (255/30/20 tire)
Rear: 20x11" 5x120mm - 31mm offset (305/25/20 tire)

http://www.turnermotorsport.com/html...ct_e90m3.shtml

I doubt that they would offer setups that result in tire rubbing.