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      11-06-2019, 01:16 PM   #40
Enlisted Member

Drives: 2017 BMW M2
Join Date: Oct 2019
Location: Michigan

iTrader: (0)

Originally Posted by toy4speed View Post
End of the season for me. Been fun with my '18 M2 LCI. Learn much about the car is available setup options.

In summary, for my B-Street class, I found I prefer the 19x10 oem rear wheel, with a 285/35-19 RE71 tire (40et offset). This is 0.5" taller in diameter than a stock tire, for slightly higher 2nd gear speed. The fronts I like the Apex SM10 wheel (30et offset) in 18x9, with a 275/35-18 RE71. This front setup cleared the fenders and strut body fine, but next year I would try to run a 8mm spacer for a wider front track. I have Apex extended studs.

Ran my Hotchkiss front bar full soft, can't see running it much stiffer as I fought understeer and mid-turn push most of the year. I will admit the car turned quite well when the RE71 front tires had good tread, but with such limited camber, the outer tire edges wore quickly, and by 50-60 runs the car turned noticeably worse. Rotating the front tires side to side did not improve the situation. Seems in B-Street, the rear tires will last an entire season easily, probably need at least 2 pairs of front tires.

On our last event of the season, my son and I ran the M2 in an SCCA STU class. Same rear whee/tire setup, but I installed GC front camber plates, home aligned approx. 3.5 deg camber, zero toe, had Apex SM10 18x10 wheels (et33 offset) with 275/35-18 RE71 in front, needing a 8mm spacer to clear the front strut body. The M2 is not currently officially listed in STU, but we entered under the NOC classing, at least for local event no issue. Anyway, the combo of wider front wheel, front camber, really transformed the car. Against some admittedly very excellent national caliber competition in well developed cars, our M2 was within 0.5 secs off top STU time (on a 71 sec course). I don't believe the M2 will ever be classed into STU by SCCA.

It was great fun driving the car, and experiencing exceptional turning ability. The car's weakness was the rear end was too loose. With this setup, I would try more camber in rear. Unfortunately, to enjoy the M2 with front camber plates, there is really no good class for the car in SCCA. Locally, my STU (light) car would be fun, but I probably would not run for points, but in BMW club events the car would be comfortably in AAA autocross classing.

Looking forward to next year!
I'm actually disappointed it wont go to STU. The Fiata is a real monster there, and the e92 M3 is also in the class which should have about the same performance envelope as the M2 since we are pretty limited on how much power can be eeked out of the stock turbo.

I have a letter into the SEB from earlier in the year about a STSS class for AS/BS/SS cars, so maybe theyll end up doing something like that and stuff the M2 in there.

Something to think about, a buddy of mine did the math and found that on a much smaller tire, the torque actually put to the ground ends up being similar to that of the M2C because its limited to the bigger rear. So unless you're banging off the limiter for really long periods of time, and arent comfortable with the heel toe downshift...its probably not worth it to run the bigger tire in the back.

Also did you change out the front steering knuckles for more camber? That might help with your push if you havent yet.

I'm also going to be playing with spacers on the front to see if I can get a wider tire up front. I know 285's have been done, but I'm not sure how much clearance that leaves up front.
2017 M2| I make poor decisions| ext 4197