[khj24]

8.5 ET 39 245/35/18 Star PSS with maybe 5/32nds left. Stock suspension and ride height. Everything I read said this cant work without camber, but I took it for a shakedown on some crap roads, over speed bumps, aggressive braking and there are absolutely no signs of rubbing on the fenders and ET39 clears the strut by some distance. Has anyone else tried something similar?

*Reposted in correct subforum*

[khj24]

Just to add onto this, the 245's in the front are absolutely INCREDIBLE. The turn in grip gives so much confidence and quick transitions from left to right and right to left are so immediate. If I had to choose a staggered fitment with the stock sizes I think I would get more enjoyment from 245's in the front and 225's in the rear. Rear traction is always an issue, but with the amount of power these cars have I think that's more of a function of not having a factory LSD. I guess you could band aid it with a more aggressive compound, but tire width isn't helping too much out back- different story up front. Long story short I think I will go 245/35/18 8.5 ET39 square unless I have any issues pop up with that fitment and would highly recommend it.

[Mark.h]

Currently running 19x8.5 +35 square. 245/35 tires. I rub on the fender with big dips. So +38 or +39 up front would be good to avoid that.

[TrboMike]

From what I've read 40-42 front offset is perfectly centered between fender and suspension and many people are running 245. So your 39 should be fine (and it is?).

[PeterWT]

I have 18x8.5 ET40 with 235/40 Michelin A/S 3+ on the OE suspension and there's no rubbing on the strut or fender liner.

If someone can confirm that 18x8.5 ET40 with 245/35 Michelin A/S 3+ (or PS4S) doesn't rub the strut or fender liner, I'll switch.

Anyone tried this combo or willing to?

TIA!

[khj24]

Originally Posted by PeterWT

I have 18x8.5 ET40 with 235/40 Michelin A/S 3+ on the OE suspension and there's no rubbing on the strut or fender liner.

If someone can confirm that 18x8.5 ET40 with 245/35 Michelin A/S 3+ (or PS4S) doesn't rub the strut or fender liner, I'll switch.

Anyone tried this combo or willing to?

TIA!

You were my reference point for putting 235/40/18 in the front so its funny this has come full circle. You will definitely clear the strut no problem, I would say there's comfortably 3mm extra clearance there. From my research the stock 245 MPSS BMW spec are quite a bit chunkier than the regular MP4S 245's, but when you replied to my other thread it looks like A/S 3s are a little bit bigger still.

I have put 70 miles or so on it with these in the front and have tried everything with the sole intention of getting them to rub and it hasn't. The ONLY thing that might be unique in this situation is that these 245s maybe have about 40% of their life left and have obviously worn away some tread depth that might have rubbed. With all of that said, considering no situation has manifested in any rub I think the WORST case scenario would be occasional rub with brand new treads on those all seasons.

[khj24]

Another observational thing- I think a lot of people that care about camber and wheel/tire mods in general lower their car immediately and talk about fitment issues on a lowered car. I dont think there is a large amount of people trying these things on the stock suspension.

[PeterWT]

Originally Posted by khj24

You were my reference point for putting 235/40/18 in the front so its funny this has come full circle. You will definitely clear the strut no problem, I would say there's comfortably 3mm extra clearance there. From my research the stock 245 MPSS BMW spec are quite a bit chunkier than the regular MP4S 245's, but when you replied to my other thread it looks like A/S 3s are a little bit bigger still.

I have put 70 miles or so on it with these in the front and have tried everything with the sole intention of getting them to rub and it hasn't. The ONLY thing that might be unique in this situation is that these 245s maybe have about 40% of their life left and have obviously worn away some tread depth that might have rubbed. With all of that said, considering no situation has manifested in any rub I think the WORST case scenario would be occasional rub with brand new treads on those all seasons.

Thanks for following up.

Here are the specs on these Michelin tires from Tire Rack:
My current tire:
Michelin PS A/S 3+, 235/40: Sect. width: 9.5 in, Tread width: 8.2 in, Dia: 25.4 in
Tire I'd like to use:
Michelin PS A/S 3+, 245/35: Sect. width: 9.8 in, Tread width: 8.8 in, Dia: 24.8 in

OE BMW Star tire in 245/35:
Michelin PSS, 245/35: Sect. width: 9.7 in, Tread width: 9.2 in, Dia: 24.8 in

Other options in 245/35:
Michelin PS 4S, 245/35: Sect. width: 9.8 in, Tread width: 8.4 in, Dia: 24.8 in
Michelin PS A/S 4, 245/35: Sect. width: 9.9 in, Tread width: 8.7 in, Dia: 25 in

I was very surprised to see that the A/S 4 has the widest section width and second widest tread width of the 4 tires I compared. And, that the PS 4S had the narrowest tread width.

So, in 245/35, the A/S 3+ has a 0.1 in (2.54 mm) wider section width and 0.4 in narrower tread width compared to the OE PSS that you tried.
But, if I compare the 2 sizes in the A/S 3+, the 245/35 has a 0.3 in (7.62 mm) wider section width and 0.6 in (15.24 mm) wider tread width compared to the 235/40.

I'll have to go measure to confirm, but I don't think I have 8 mm clearance on the strut right now. I think I have more like 2-3 mm. So, I don't think the A/S 3+ in 245/35 will fit in the front on an 8.5 ET40 wheel.

[khj24]

Originally Posted by PeterWT

Thanks for following up.

Here are the specs on these Michelin tires from Tire Rack:
My current tire:
Michelin PS A/S 3+, 235/40: Sect. width: 9.5 in, Tread width: 8.2 in, Dia: 25.4 in
Tire I'd like to use:
Michelin PS A/S 3+, 245/35: Sect. width: 9.8 in, Tread width: 8.8 in, Dia: 24.8 in

OE BMW Star tire in 245/35:
Michelin PSS, 245/35: Sect. width: 9.7 in, Tread width: 9.2 in, Dia: 24.8 in

Other options in 245/35:
Michelin PS 4S, 245/35: Sect. width: 9.8 in, Tread width: 8.4 in, Dia: 24.8 in
Michelin PS A/S 4, 245/35: Sect. width: 9.9 in, Tread width: 8.7 in, Dia: 25 in

I was very surprised to see that the A/S 4 has the widest section width and second widest tread width of the 4 tires I compared. And, that the PS 4S had the narrowest tread width.

So, in 245/35, the A/S 3+ has a 0.1 in (2.54 mm) wider section width and 0.4 in narrower tread width compared to the OE PSS that you tried.
But, if I compare the 2 sizes in the A/S 3+, the 245/35 has a 0.3 in (7.62 mm) wider section width and 0.6 in (15.24 mm) wider tread width compared to the 235/40.

I'll have to go measure to confirm, but I don't think I have 8 mm clearance on the strut right now. I think I have more like 2-3 mm. So, I don't think the A/S 3+ in 245/35 will fit in the front on an 8.5 ET40 wheel.

Correct me if I am wrong, but I think it would only be half of that section width, not the full amount. If you compare what I am running to the AS3 in 245 it would be 1.27mm closer to the strut, which there's plenty of room for. I think we both have the 437m OEM concept wheels so I would say we are most likely both at ET39 or ET40. I wouldn't worry about tread width with regards to strut clearance, section will be the one for that. Another thing to keep in mind with converting from inches to MM are rounding implications since every .1 in is 2.54mm.

[PeterWT]

Originally Posted by khj24

Correct me if I am wrong, but I think it would only be half of that section width, not the full amount. If you compare what I am running to the AS3 in 245 it would be 1.27mm closer to the strut, which there's plenty of room for. I think we both have the 437m OEM concept wheels so I would say we are most likely both at ET39 or ET40. I wouldn't worry about tread width with regards to strut clearance, section will be the one for that. Another thing to keep in mind with converting from inches to MM are rounding implications since every .1 in is 2.54mm.

Yes, you're correct. It was late last night when I typed that. ;-)
The the 245/35 A/S 3+ would be 3.8 mm closer to the strut than the 235/40 I have now. I'll have to measure how much clearance I have now, but I don't think it's 4 mm. And, the 0.6 in wider tread width could result in a rub on the fender liner. :-(

Don't get me wrong, I still think it might be possible, but I'm skeptical that I have enough clearance on the strut for the 9.8 in section width of that 245/35 A/S 3+ and that the wider tread width won't rub the fender liner.
My front tires only have ~8K miles on them, but if I knew for sure the A/S 3+ 245/35 wouldn't rub and I could still get them, I'd order them right now.
Tire Rack has them on clearance for ~$150 ea. I'm tempted...

Also, I don't have the OEM concept wheels anymore. I have APEX EC-7 8.5 ET45, w/ 5 mm spacers. So, the effective offset is exactly ET40.
Yours are ET38-39, depending on the starting offset and how much they machined. I measured mine when I had them. They were approximately ET39.

[khj24]

Originally Posted by PeterWT

Yes, you're correct. It was late last night when I typed that. ;-)
The the 245/35 A/S 3+ would be 3.8 mm closer to the strut than the 235/40 I have now. I'll have to measure how much clearance I have now, but I don't think it's 4 mm. And, the 0.6 in wider tread width could result in a rub on the fender liner. :-(

Don't get me wrong, I still think it might be possible, but I'm skeptical that I have enough clearance on the strut for the 9.8 in section width of that 245/35 A/S 3+ and that the wider tread width won't rub the fender liner.
My front tires only have ~8K miles on them, but if I knew for sure the A/S 3+ 245/35 wouldn't rub and I could still get them, I'd order them right now.
Tire Rack has them on clearance for ~$150 ea. I'm tempted...

Also, I don't have the OEM concept wheels anymore. I have APEX EC-7 8.5 ET45, w/ 5 mm spacers. So, the effective offset is exactly ET40.
Yours are ET38-39, depending on the starting offset and how much they machined. I measured mine when I had them. They were approximately ET39.

I think this is clearly why black and white fitment info is basically non existent for us on the F2X platform. It seems as if fitment is just something one does and others follow when they get the all clear. When you talk about a reasonably large investment to get new tires installed without certainty of adequate fitment most wont take that leap.

If only you had 245's on the rear you could play around with like I was able to, that's really the only reason why I know it fits.