[fhlh]

Originally Posted by Polo08816

MPSS 255/40/18 (which is a wide tire) on 18x8.5 ET38 will clear the front struts.

I would go with 255/40/18 instead of 245/40/18 because you have a bit more sidewall.

I may end up with a set of 18x8.5 et38's for autox, but I'm digging this setup right now

[T4NZ4NIT3 335i]

2013 335i xdrive

tires: MPSS 255/40/18 on 18x8.5 35 offset.

Suspension: Bilstein B6 with AC Shnitzer lowering springs.

No rub at full lock or bumps.

[Adaptive]

The above setup looks pretty awesome. I have a 2015 328i xdrive noline. Is the suspension similar enough to the above that I would not have any issues running a 255/40-18 on an 8.5 ET 38 wheel like the Enkei Rajin ?

[nadthomas]

Originally Posted by Adaptive

The above setup looks pretty awesome. I have a 2015 328i xdrive noline. Is the suspension similar enough to the above that I would not have any issues running a 255/40-18 on an 8.5 ET 38 wheel like the Enkei Rajin ?

Yeah, you should be fine if you are looking at MPSS tires, other tires may run a little wider and may rub. I couldn't tell you if the new version of the MPSS run any wider.


BTW another update to my original post. I now have almost two summers on my 18x9 et42 w/ MPSS 255/40/18 with no issues. Even with the Eibach Sportline springs now on the car there is still no rub. Not even on a kind of rough AutoX course. This is with no spacers, or fender rolling, etc.

[Adaptive]

I looked on Tire Rack and it was interesting that there were 3 different listings for the MPSS in 255/40R18! I am interested in the RE-71R. Here is what Tire Rack lists for the tread widths...

Tread Widths from Tire Rack:
Pilot Super Sport 255/40ZR18: 9.2” [255/40ZR18, (99Y) XL, Star BMW]
Pilot Super Sport 255/40ZR18: 8.5” [255/40ZR18, (95Y) SL, Star BMW]
Pilot Super Sport 255/40ZR18: 9.5” [255/40ZR18, (99Y) XL]
Potenza RE-71R 255/40R18: 8.9”

I am thinking of putting these on an 18x8.5 rim with ET between 35-38 ...

[Adaptive]

nadthomas
Its so tempting to try and emulate this but virtually noone lists anything wider than an 8.5 [rim] working in the front and the only references that I have found to a 255 tire working in the front are all in this forum thread! Its so tempting to try it but, man, maybe you were just really lucky!

As an aside, it seems you are really happy with how it worked out. I have a 328 also, and it sounds like no issues with the lighter/wider wheels/tires slowing things down any. Obviously the extra grip is SWEET on the autoX course, but does it also drive well tooling around town?

Thanks so much for the help and feedback!

[alohasurftoad]

18x8.5 +35 or 18x9 +35 will work. the only thing that changes is 255/40/18 is a hair oversize (slight bulge) on 8.5" but perfect fit (vertical sidewall) on 9"

[Adaptive]

So I went with the Bathurst 18x8.5 with 245/40-18 RE-71R.



Link to pic cause I cant figure out how to do it inline...

[nadthomas]

Sorry for the late reply, I stopped getting notifications on this thread for some reason. For anyone else that is looking in the future. I did research this a for several weeks looking for others members that had the same setup, I did eventually find a few after scouring numerous wheel and tire threads. That was good enough for me to pull the trigger. Also, if push came to shove I was willing to put a small spacer on if it was needed, but in the end spacer were not necessary.

As for the different tire widths of 255/40/18 MPSS, as I recall the 9.5" width was a Mercedes(AMG) spec built tire. IIRC I went with the 9.2" width, I'll try to remember to check my sidewall tonight.

I have been extremely happy with this setup. My car is a year round daily driver, and the car just hit 50k miles this week. The car drives great on normal roads on this setup, frankly I like it better then stock. Until I installed this wheel/tire setup I always found the on center feeling of this car to be a little numb. The wider wheels and tires seemed to fix that. It does of course track ruts in the road just a little, but it has to be pretty uneven and even then I only notice it because I'm looking for it(and thinking if I could/should go even wider).

I have also been really happy with the MPSS they have surprised me in all driving conditions(except snow/ice obviously). Although I did keep them on the car into mid November last year. They still had confident traction on 40F wet roads. The BFG KDW2 that I used to run on my GTO were scary on dry roads at 40F. The MPSS have also held up well at autox events.

[ceedawg]

Originally Posted by alohasurftoad

18x8.5 +35 or 18x9 +35 will work. the only thing that changes is 255/40/18 is a hair oversize (slight bulge) on 8.5" but perfect fit (vertical sidewall) on 9"

Would it be a bad thing/unsafe for road racing if there were a slight bulge using the 255 40 18s on the stock 8.5 inch width rims?

[alohasurftoad]

Originally Posted by ceedawg

Would it be a bad thing/unsafe for road racing if there were a slight bulge using the 255 40 18s on the stock 8.5 inch width rims?

most max performance summer tire sidewalls are pretty stiff. i suppose if you are a seasoned track or professional driver you might notice a hair slower turn in. you want some sidewall flex to maintain maximum contact patch and slower breakaway, unless you're drifting.

oem 8.5" rear wheels come with 255's. each tire bead of a 255 on 8.5" is being squeezed in 1/4" to the bead seats, which causes the bulge. it's not much but that is the max width oversize at this profile.

255 on 8.5 is fine

[ceedawg]

Originally Posted by alohasurftoad

most max performance summer tire sidewalls are pretty stiff. i suppose if you are a seasoned track or professional driver you might notice a hair slower turn in. you want some sidewall flex to maintain maximum contact patch and slower breakaway, unless you're drifting.

oem 8.5" rear wheels come with 255's. each tire bead of a 255 on 8.5" is being squeezed in 1/4" to the bead seats, which causes the bulge. it's not much but that is the max width oversize at this profile.

255 on 8.5 is fine

Sadly I have a bad feeling the width on my Xdrive with Msport rims, maybe 8 inches wide but I cannot confirm ,will that still be a problem with 255 40's though you Think? Not a professional but will roadrace at NJMP. Car presently has 225's all around. I am hoping the rears are 8.5 and fronts are 8.0 I have the 400M style rims

[alohasurftoad]

Originally Posted by ceedawg

Sadly I have a bad feeling the width on my Xdrive with Msport rims, maybe 8 inches wide but I cannot confirm ,will that still be a problem with 255 40's though you Think? Not a professional but will roadrace at NJMP. Car presently has 225's all around. I am hoping the rears are 8.5 and fronts are 8.0 I have the 400M style rims

if you have 225 square then your 400m are 18x8 square. you can do 245/40/18 square which will be fine and way better than 225 square.

http://f30.bimmerpost.com/forums/sho...d.php?t=831520

[ceedawg]

Originally Posted by alohasurftoad

if you have 225 square then your 400m are 18x8 square. you can do 245/40/18 square which will be fine and way better than 225 square.

http://f30.bimmerpost.com/forums/sho...d.php?t=831520

Perfect thankyou man I am going to order some 245 40's all around then . I am also under the belief that maybe the fronts are 8.0 wide and the rears are 8.5 ,only means I will have a rotation issue. So that will perhaps mean I will have to keep replacing the front tires more often like I do on my AMG.

[ceedawg]

Originally Posted by alohasurftoad

if you have 225 square then your 400m are 18x8 square. you can do 245/40/18 square which will be fine and way better than 225 square.

http://f30.bimmerpost.com/forums/sho...d.php?t=831520

Ahh in reading that thread the guy is saying the rims are 8 inches all around Kool BEANS

[AZ-M007]

I have seen few Bmw 335xi with square setup of 255 40 18 with no issue, as in this forum few have done with same setup without any mod.
Interesting thing is that, I am running 245/45/18 with no issue. Yes 245/45/18 but these are my winter tires on Oem wheels. I didn’t install purposely but I had 4 tires in my garage from my previous car that I sold, so thought to try it. And it works. They are bit taller but no rub or any issue, so if they are ok not perfect then 255 40 18 can be installed. Trust me.

[RbBugBitMe]

Resurrection! I'm not seeing many pictures in this thread for 18x9's with 255/40s. Who has some?

What I'm still looking into is with say an ET30 or 35, do the front and rear end up flush looking or do I need a spacer for one end or the other?

[carseatdelete]

Originally Posted by RbBugBitMe

Resurrection! I'm not seeing many pictures in this thread for 18x9's with 255/40s. Who has some?

What I'm still looking into is with say an ET30 or 35, do the front and rear end up flush looking or do I need a spacer for one end or the other?

Check out the post I just put up here:


https://www.bimmerpost.com/forums/sh...php?p=27022773

[RbBugBitMe]

Originally Posted by carseatdelete

Check out the post I just put up here:


https://www.bimmerpost.com/forums/sh...php?p=27022773

Link no worky. Found it here. https://f30.bimmerpost.com/forums/sh...&postcount=162

Thanks for posting, that is some meat!

[carseatdelete]

Originally Posted by RbBugBitMe

Link no worky. Found it here. https://f30.bimmerpost.com/forums/sh...;postcount=162

Thanks for posting, that is some meat!

Glad you found it!

Road quality around here is abysmal. I tried 235/40/18 based on Apex fitment guide last year and ride quality was horrifying.

Very happy with 255/40/18 and also same diameter as my winter spec 225/45/18 so easy to swap with aesthetics / suspension setup unchanged.

[TheJungatron]

245 square, been running it on 18's for about 2 years.

[clemsonf31]

Originally Posted by RbBugBitMe

Resurrection! I'm not seeing many pictures in this thread for 18x9's with 255/40s. Who has some?

What I'm still looking into is with say an ET30 or 35, do the front and rear end up flush looking or do I need a spacer for one end or the other?

18x9 et31 Apex EC-7 with 255/40/18 MPAS3+
Xdrive and no rubbing whatsoever

Max