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[xQx]

I've run a number of crappy-brand 255/35R18 tires on the back of my E88 without issue; but (thankfully) upgraded to MPS4's recently.

Unfortunately, they seem wider than usual, and are rubbing on the outside whenever I go over a bump.

As a result, the outside shoulders of the tire are being torn to shreds by the body of the car.

I'm interested to know others' experiences; and especially what your recommendations are for a fix.

Should I get the guards rolled (and if I do - should I do the fronts at the same time and does it open up the possibility of even wider tires) - or should I keep a close eye on it and go 245's next time?

[Eyeman]

That's pretty bad. I'd take it to an alignment shop to have them increase your rear camber.

Rolling and pulling will help somewhat. But I bet you are mainly rubbing where the rear bumper connects to the fender and it's hard to do much with that area.

Michelin's don't so much run big as many cheap tires run small. Many of us have been through this but mainly because we have aftermarket wheels.

[dojk]

Are you on stock suspension?

I used to have Hankook S1 Evo2 in 255 for the rear. Couple months back I went for the new Conti Extreme ContactSport also in 255. The Contis were definately wider than the Hankooks but I have yet to experience any rubbing whatsoever.

[xQx]

Originally Posted by dojk

Are you on stock suspension?

Yes, stock m-sport suspension. I was a bit surprised, I've been running 255/40's at the back since I got the car.

MPS4's have been the first to cause any issues.

[Esteban]

You're speaking about the Michelin Pilot Sport 4, and not the Michelin Pilot Sport 4S, is that correct? I ask because I have just purchased Michelin Pilot Sport 4S 225/255 for my car (not installed yet), but I have the the Michelin PSSs in 225/255 that fit with no issues at all and I assume the MPS4Ss will fit the same as the MPSSs.

[c1pher]

Originally Posted by Esteban

You're speaking about the Michelin Pilot Sport 4, and not the Michelin Pilot Sport 4S, is that correct? I ask because I have just purchased Michelin Pilot Sport 4S 225/255 for my car (not installed yet), but I have the the Michelin PSSs in 225/255 that fit with no issues at all and I assume the MPS4Ss will fit the same as the MPSSs.

I run the same size Michelin AS3+ without any issues either. Maybe the shoulder isn't as rounded to give it more of a contact patch?

[MightyMouseTech]

Looks like you just need an alignment and increase rear camber to -2.2 or so.

Was having the same problem with my 265's on one side. Thought I had -2.0 on both sides. Turns out our alignment rack was off, and actually had -1.4 on one side and -2.6 on the other when I redid it on our new alignment rack.

[xQx]

Originally Posted by Esteban

You're speaking about the Michelin Pilot Sport 4, and not the Michelin Pilot Sport 4S, is that correct? I ask because I have just purchased Michelin Pilot Sport 4S 225/255 for my car (not installed yet), but I have the the Michelin PSSs in 225/255 that fit with no issues at all and I assume the MPS4Ss will fit the same as the MPSSs.

Yes, Not the 4S.

I've never had MPSS or MPS4S's on the car, so I can't compare. Essentially the only other 255's I've had on were some cheap shitty asian brand tires.

I'm in a convertible with M-Sport suspension, so I might be lower than the average 1er. It's less of a problem with -2.0 camber; but still not completely cured.

[Jason135i]

Why not just buy the right size tire for your car? I don’t get why people always buy oversized tires and wheels that don’t fit.

[Matt@EuroJerks]

Originally Posted by Jason135i

Why not just buy the right size tire for your car? I don’t get why people always buy oversized tires and wheels that don’t fit.

Scene "seen" points!!!!

[xQx]

Originally Posted by Jason135i

Why not just buy the right size tire for your car? I don’t get why people always buy oversized tires and wheels that don’t fit.

Well, to be fair, I wasn't trying to buy oversized tires that don't fit, I was trying to buy the widest tires that do fit. You can check if the tire fits on the rim here, and check the specs of your OEM rims here. There's also a helpful thread about what will fit without issues here. Finally, when I bought the car it was running 255/40r18's up the back, so you'd assume changing tire brands but running the same size tires wouldn't cause issues.

So, why do people bother running bigger tires than stock; well, for starters, BMW gave us shitty runflats, so you can't exactly say they chose the best possible tires for performance out of the factory. Now, simple physics tells us that running wider tires does nothing to increase the overall size of the contact patch between the wheel and the road; it just changes it from a long skinny contact patch to a wide and short contact patch - so, the amount of friction between your car and the road doesn't change. BUT, tires rely on adhesion to stick to the road, not just friction; so you're really not going to know if it does anything until someone does some real-world side-by-side testing on a track to see if wider tires mean faster track times or shorter stopping distances.

Oh wait, they have.

Now, I don't know about you; but in my little car, the biggest impediment to me accelerating faster below 100kph is my rear-wheel traction; and my personal preference is to have a car with the shortest possible stopping distances - so it seemed worthwhile to run better and wider tires than BMW shipped the car with from the factory.

[Matt@EuroJerks]

Originally Posted by xQx

Well, to be fair,......
Now, I don't know about you; but in my little car, the biggest impediment to me accelerating faster below 100kph is my rear-wheel traction; and my personal preference is to have a car with the shortest possible stopping distances - so it seemed worthwhile to run better and wider tires than BMW shipped the car with from the factory.

I enjoyed your TED talk. Will come again!!