Maximum wheels sizes

All the info you need to race E30's

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bigdry
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Thu Aug 11, 2005 5:18 pm

Hello all, can you tell me if 8 and 9" wide rims will fit under standard m3 arches or will they only fit under a sport evos arches. If so what is the maximum width that can be fitted to a standard m3? also what offset will be needed.
Manythanks

Rocco
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GermanGorilla
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Tue Aug 16, 2005 9:43 am

Hi,

Bit rude that no one has replied since you have only just recently joined.

I am no expert, but from my own experince I hope you find the following usefull.

E30 M3

1. The 'larger' Evo Sport Arches are for larger diameter wheels ie 18'', the flare on all M3 Arches for wheel width is exactly the same.

2. 17'' Wheels with offset of ET 13 - 22 for the front and 17 '' Wheels with offset ET 13 -25 for the rears are about right, ideal set up with 17'' wheels is ET 20 Front say 8'' wide, and ET 22 Rear 9'' wide.

3. Width of Front wheels can be anything up to about 8.5'' wide, any wider and you will incur rubbing issues on full lock.

4. Width of Rear wheels can be anything up to about 9.0'' wide, you can fit
10'' wide rears but you will run into tyre issues.

5. Tyre size and the important rolling circumfirance come into play with Tyres which is little understood.
For example if you run 225 40 17'' front and 245 40 17'' rears, your rear wheels are turning slower than your front as they have an overall larger diamater.
That is why if you look at most cars with wider rear tyres, the fronts will be say 225 40 17'' and the rears should be 245 35 17''. This sizing matches the overall diameter as close as possible.
A popular choice on the E30 M3 is 235 40 17'' all round.

6. When going to 18 wheels the tyre issues become even harder in maintaining the correct sizing, due to manufactures size range.
Also 18'' wheels with a 40 profile is very tight on the front, much rubbing, so if you go 18'' wheels with 35 profile tyres on the front, you are looking at 30 profile rears for the rear, if you require wider. Still its your money.

7. Last, the 'X' Factor, or the clearance between the calipers and the wheel spokes. If you have standard Calipers then most wheels seem to fit, the moment you switch to a Big Brake Kit, then clearance issues will most certainly occur.

Hope this assists with your research.

The Gorilla.
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karlp
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Sun Aug 21, 2005 11:16 am

I havbe just fitted a set of wide wheelsa to my M3 race car.

8J * 15 with ET7 offset. These will fit front ok but rear arches will need rolling.

If do not wish to roll arches then need larger offset probably et13.

Karl
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Sat Aug 27, 2005 10:40 am

You going to run the 225 tyre Karl?
please contact admin with regard to sig
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karlp
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Sat Aug 27, 2005 12:07 pm

At present got the 205 tyre on them. According to Kuhmo this is the max rim size that will fit these tyres AND I got the rims mega cheap (Compomotive MO).

Not sure about the wider tyre but still considering.

Karl
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Tue Oct 04, 2005 11:07 am

Ive have just fitted 8x18 M Parallel wheels et15 to my E30 M3

I got 215/35/18 on the advise of other forum users....they fit a treat with the small drop in ride height.
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lancelot
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Wed Oct 05, 2005 2:45 pm

If anyone is looking for some track wheels I have 4 Compomotive Mo's in 8x15 et0 that I have used on my e30 m3. They do fit but you need to have your rear arches fettled to get them to fit if you want to run really low. I know a lot of the Kumho guys use these as they increase the track a bit which majes the car very stable. I don't want to attack my arches as mine is a road/trackday car, so am reverting back to smaller wheels for track days. Pics of the wheels on the car here Image
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