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      09-04-2014, 10:10 PM   #1
desmoto
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Z4M widest usable 18" fitment? (stock suspension + F camber)

OK, so I know there's a lot of discussion on this topic all over the forum BUT there's a bit of contradication and I'm hoping to compile some clear answers here.

So I'm reaching out to all you savvy ///M owners:

what's the widest practical fitment in 18" for our cars, assuming ~ -2.5 front camber via plates or washers and otherwise stock suspension?

I would like to run 255/275, 265 square or 265/285.
Within reason, the more rubber and less stagger the better, right?

Car will receive stud conversion with these wheels and I'm fine with spacers as needed.

Considering:
18x9 et 42 or 18x9.5 et35 Front
18x9.5 or 18x10 rear et??

Application will be occasional DD/autox/trackdays.

The car is running heavy-ass 19s currently and they need to go. Next year I'll buy some flossy street wheels and coils. Right now I want to buy a some sizing that I'll be able to run DD as needed without hassle but will eventually become a dedicated track setup.

Help me out with the details guys. Much appreciated.
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      09-05-2014, 12:39 AM   #2
seank
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I believe the widest within the camber you specified and not sticking out is 18x9 et35 with 245 front and an 18x9.5 et35 rear with 265.

18x9.5 et35 265 front will stick out 1/4 inch.
18x10 et35 with 265 rear will fit but 275 will stick out 1/4 inch.

As far as track set-up, i only know e30m3's. The very few with stock to super charger will debate the tire set-up. I even think the wise one, known as the The Hack, has had multiple posts disagreeing with himself over tire set-up. Regardless, we know it is the one that allows you to brake the latest and get on the power the soonest. When the weight is stripped out, you can add going through the corners fast too.
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      09-05-2014, 01:48 PM   #3
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Quote:
Originally Posted by seank View Post
I believe the widest within the camber you specified and not sticking out is 18x9 et35 with 245 front and an 18x9.5 et35 rear with 265.

18x9.5 et35 265 front will stick out 1/4 inch.
18x10 et35 with 265 rear will fit but 275 will stick out 1/4 inch.

As far as track set-up, i only know e30m3's. The very few with stock to super charger will debate the tire set-up. I even think the wise one, known as the The Hack, has had multiple posts disagreeing with himself over tire set-up. Regardless, we know it is the one that allows you to brake the latest and get on the power the soonest. When the weight is stripped out, you can add going through the corners fast too.
I agree with the front fitment, but not the rear. I run 18x10" rears with ET 32 and 265/35 tires. The wheels are slightly tucked (5 mm to be flush with fender) and the tires are minimally stretched. The wheels/tires as they are now clear the inner fender liner with 8-10 mm. The outer clearance is about 10 mm. I'm lowered about 35 mm though. If you go for 275/35 tires I would go with 18x10" ET 27.

Up front I have 18x8.5" with ET 38 and 235/40 tires. I could use a 10 mm spacer to be flush with the fender, but that might cause a rub on the outer fender liner under hard cornering (5 mm should be no problem). No tire stretch and the inner clearance I have no idea. This setup NEVER rubs. If you go for 9" fronts I'd recommend ET 35.

Stock camber front and rear. In your case I wouldn't run wider than 245/40 up front and 275/35 in the rear. It will most likely provide more grip than you'll dare to use anyway, if you buy quality tires.
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      09-22-2014, 08:12 PM   #4
desmoto
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Thanks for input guys!

I actually ended up with a fairly conservative setup because I came across a great deal on a set of 18x8.5/9.5 BBS RS-GT.

The wheels are higher offset than ideal for the M Coupe, but that allows me to play around with spacers to fine-tune the fit.

Current setup: et33 front 235/40/18 and et25 rear 265/35/18

With those offsets the rear is tucked slightly with camber around -1.2 (et20 would probably take it there but I want to fit 275 rear so I'm holding at et25) and the front was almost flush before adding camber washers, now I have tons of room w/ two washers fitted.

Notes:

265/35/18 on 18x9.5 rubbed fender liners at et40 badly, rubbed slightly under compression at et35, good clearance either way at et25. I think there's room for 285 under there but we'll see...

235/40/18 on 18x8.5 cleared the strut with no problem at et38, looks much better on stockish camber at et33. 5mm spacer + 2 camber washers fitted gives me about a fingers width between tire and strut, TONS of room to the fender. Easily another 8-10mm of room there before approaching contact with the fender.
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      09-22-2014, 08:28 PM   #5
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quick pic of the new shoes

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      09-22-2014, 09:58 PM   #6
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Very nice.
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      09-23-2014, 04:30 PM   #7
VMRWheels
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Congrats on the new setup!
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      09-25-2014, 02:56 PM   #8
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Quote:
Originally Posted by desmoto View Post
Notes:

265/35/18 on 18x9.5 rubbed fender liners at et40 badly, rubbed slightly under compression at et35, good clearance either way at et25. I think there's room for 285 under there but we'll see...
That's really wierd. My 18x10" 265/35/18 ET 32 have never rubbed and judging from your pictures I'm slightly lower as well.

That a side, really nice wheels!
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