Ideal wheel/tire size

[Colinoscopy]

I know this has been asked. I've searched all the threads and there doesn't seem to be a solid consensus, so I'm asking again. I'm looking for a combo with more straight line grip as I spin off the line almost every time. I'm currently running (18 x 8) 225 40 18 all around. I have a 2010 M sport 135.

From thread researching it seems that 235 40 18 on the front and 265 35 18 on the back seems to be the largest we can fit on the stock M sport suspension. Is this true? Also, I've heard you can get bad under-steer when the front and rear tire discrepancies are large. Thoughts on this?

Thanks so much.

[Accrual_World]

Originally Posted by Colinoscopy

I know this has been asked. I've searched all the threads and there doesn't seem to be a solid consensus, so I'm asking again. I'm looking for a combo with more straight line grip as I spin off the line almost every time. I'm currently running (18 x 8) 225 40 18 all around. I have a 2010 M sport 135.

From thread researching it seems that 235 40 18 on the front and 265 35 18 on the back seems to be the largest we can fit on the stock M sport suspension. Is this true? Also, I've heard you can get bad under-steer when the front and rear tire discrepancies are large. Thoughts on this?

Thanks so much.

When I first bought my 1 it had 225s on all four corners as well, I didn't enjoy it, as spinning tire was too easy and grip wasn't great.

What I ended up doing was keeping the 225s up front and throwing 255s in the rear with 18x8+45 wheels. Big difference it has made, especially launching and/or hitting WOT in a lower gear. If there was any added under-steer, it has not been noticeable at all during spirited driving, it is still pretty easy to get the rear end to kick around.

What will fit depends on a few factors, wheel dimensions and offset and tire size. There are quite a few combinations that would fit just fine with tire sizes over 225. For example, with the right wheels and offset you can definitely fit 235s up front and 265s in the rear (although you will likely be running the max size tire for a given wheel width, maybe even one size bigger). I'd just recommend going the 225/255 combo route.

If you check out the "OFFICIAL Wheel/Tire Fitment Thread" you can find a lot of good info.

[Soterios]

I'm running 235 up front and 265 in back and rub tires. I have NITTO NT05 tires which do have blocky shoulders, but even with some fender rolling I rub. (negative camber coming soon)

So tire matters with regards to max width. Not all tires are created equal.

As Accrual pointed out, the Wheel/Tire thread is where you should check out what will and won't work. Not every wheel/tire combo is in there, but you'll get a good idea.

[beattiecj]

I ran the following without issue on stock M-Sport suspension and no rubbing, the offset of the rim itself can cause issues with rubbing as well. The RS4 is a 200TW tire that runs slightly larger as well.

Front:
Rim: Apex EC-7 18x8.5" ET45
Tire: 235/40ZR-18 HANKOOK VENTUS R-S4

Rear:
Rim: Apex EC-7 18x9.5" ET58
Tire: 265/35ZR-18 HANKOOK VENTUS R-S4

In my opinion you really shouldn't be worried about too much understeer for daily driving at the track yes, stock form its terrible. Running a staggered setup is fine, square is nice for rotating tires.

On stock wheels I did fit a 255 Michelin Pilot Super Sport with plenty of space on the rear.

[Colinoscopy]

Originally Posted by beattiecj

I ran the following without issue on stock M-Sport suspension and no rubbing, the offset of the rim itself can cause issues with rubbing as well. The RS4 is a 200TW tire that runs slightly larger as well.

Front:
Rim: Apex EC-7 18x8.5" ET45
Tire: 235/40ZR-18 HANKOOK VENTUS R-S4

Rear:
Rim: Apex EC-7 18x9.5" ET58
Tire: 265/35ZR-18 HANKOOK VENTUS R-S4

In my opinion you really shouldn't be worried about too much understeer for daily driving at the track yes, stock form its terrible. Running a staggered setup is fine, square is nice for rotating tires.

On stock wheels I did fit a 255 Michelin Pilot Super Sport with plenty of space on the rear.

Thanks everyone for the replies, they've been super helpful. beattiecj do you think you were able to fit those 265's purely because of the 58 offset? I ask because I think Apex might be out of my price range, but I found some VMR VB3's 18 x 8.5 ET35 up front and 18 x 9.5 ET45 in the back that I'm wondering will fit your same tire setup?

[beattiecj]

I believe it's because of the offset, but also know people run VMRs with no issue. Worse case contact VMR and tell them what you want to do and I'm sure they can help you out. Apex is also very helpful.

[ShocknAwe]

I'd save up for Apex wheels. Can easily fit 275/35 MPS4S on their +58 18" offerings. The front is more tricky but you can fit a 245-255 up there with some camber mods and a 9" wheel.

If you want to keep it simple, I'd stick with 225/255. Square, do the front work and run 245.

Wheel offset is the most important factor to fitting rubber under the fenders of these cars.

[smi2710]

09 135i Stock wheels running a bilstein B12 suspension and i am running 255 indy firehawk500 in the rear and 225 up front, no rubbing what so ever rear grip is great however i do get understeer running autocross but for daily driving and even a track day it has been great with this set up.

[MightyMouseTech]

Running 245/265 MPSS on Apex wheels with zero rub.

Gotta pay to play.