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[drwankel]

Hi all,

Making a dedicated thread on this in hopes of capturing insight from folks on this issue, and helping anybody who might hit this in the future.

The car itself is a 2012 e92 ZCP, stock suspension. it has a harrop supercharger installed, so there is a bit of extra weight in the engine bay.

The wheel upgrade as as follows. 19x11 + 25 rear, 295/30/19 tires, 19x10 + 25 front, 275/30/19 tires. Tires are Michelin PS4S tires.

Rear tires appear to be totally fine.

The fronts on the other hand appear to be rubbing in two places. The rear of the fender liner (pics attached) and some very slight rubbing on the inner edge of the bumper cover. The rubbing is identical on both sides.

Despite endless research claiming this shouldn't rub on stock ZCP suspension, it does. The fender liner rubbing occurs while stationary and turning the steering wheel greater than 60% left or right from center. The tires have about 20 miles on them, and I strongly suspect that if this is left unchecked, it will rub through the liner.

There are two things I am considering- and this is what I am trying to gather opinions on

Many people who are running this setup are lowered. Lowering the car would add some negative camber. Would pulling the alignment pins and adding a touch of negative camber give some additional clearance on the rear of the front fender liner? A more aggressive fix would be to lower the car with springs to induce some negative camber.

The second approach I am looking at is changing to a 265/30/19 tire in the front. I'm wondering if the Michelin PS4S may run a bit taller and wider at a given size than other tires which may be contributing to the rubbing.

Adding some negative camber would be the preferred approach if this is a worthwhile fix, as I don't have to go buy another set of front tires (again).

Thoughts?

[nycplumber]

That spot rubs worse on 255/35/19 as its diameter is .4" bigger, which is what most people run. Camber isn't going to change that, caster would. I'm guessing the rub isn't bad and will likely not be an issue. FWIW a 265/30/19 is only .3 smaller in diameter so it will only give you roughly 1/8th

[drwankel]

Originally Posted by nycplumber

That spot rubs worse on 255/35/19 as its diameter is .4" bigger, which is what most people run. Camber isn't going to change that, caster would. I'm guessing the rub isn't bad and will likely not be an issue. FWIW a 265/30/19 is only .3 smaller in diameter so it will only give you roughly 1/8th

Keep in mind that that rub mark is the result of only 20 miles of driving. So it doesn't look bad... yet. It only hits when turning the wheel in parking lot situations. Ive basically parked the car while I figure out my options, as I don't want to make it worse.

The thought behind adding a bit of camber would be that tilting the wheel up would pull the top of the wheel in a bit and reduce the area that can be contacted by the edge of the tires. It sounds right, but I may be understanding it wrong.

[nycplumber]

Strange because I just looked up stock diameter of a 245/40/18 and that's actually 0.1 larger than a 275/30/19. I had same issue with a bigger tire and it never became a problem. I think youre fine unless you're doing 50mph in your local Costco parking lot lol

[drwankel]

After doing a alot more reading I think this is the approach that I am going to try first based on some guidance from here:

https://support.apexraceparts.com/hc...revent-Rubbing

After scouring the forum- I can see a few reports of people rubbing but most of these reports are many years old. The people that say they dont have rubbing with this setup have one thing in common- they are lowered. Lowering the car WILL add negative camber.

Guidance from the link above states:

"Fender liner rubbing - The outer shoulder of the front tires rub the front plastic fender liners while making full-lock turns.

Solution-

1. Add front negative camber
2. Reduce tire size
3. Remove fender liners"

Based on this I will get an alignment this week and have the the alignment pins pulled to add some negative camber. The goal here is to add negative camber as well as make sure the rest of the car is aligned correctly. If this fixes it, great. If not I will test fit some 265/30s on the front combined with the negative camber from the alignment, and hopefully that will fix it.

Another thing that seems evident is that Michelin PS4S tires run a bit wider and taller than other brands of tires, which could also explain some of the variability.

Will report back.

[m3boost]

Just swap the tires to the correct size, all that work, and you will still have a tire too big with affects how the car performs. Negative camber will eat those tires for breakfast too.

[M43S7RO]

I had rub at rear liners only up front on 19" 275/30 ad08r at full lock. I was -2 camber. My solution was not make full lock turns. Given my experience, i dont think adding camber is gonna help.

I imagine you are also rubbing at front is because the ps4s are prob bigger than ad08r.

I now run 285/30 re71 up front on 18" wheels with no rub, same camber (smaller total diameter).

[drwankel]

Originally Posted by m3boost

Just swap the tires to the correct size, all that work, and you will still have a tire too big with affects how the car performs. Negative camber will eat those tires for breakfast too.

To be clear here- the goal isn't an insane amount of camber, just to replicate a similar amount of camber as one would get from installing lowering springs. Pulling the alignment pins seems to net a max possible gain of 0.5 additional camber.

Tons of people that have lowered their car here leaving the alignment pins in tact, and I don't see rampant or really any reports of that bit of camber negatively affecting handling (some say its a plus) or destroying tires.

People that slam the car and add camber plates, that's a totally different story and not the goal.

There is the other issue where I have a very slight amount of rubbing on the edge of the wheel well on the bumper cover, so a touch of negative camber will help that as well.

I have no guarantee that a 265/30 is going to fix it, so I'm going to explore alignment first. If the end result is something that ruins handling and destroys tires, I absolutely wont do it. I'd rather go back to the stock wheels before I end up with results like that.

Again- the intention here is to see if a bit of negative camber will resolve the issue, if not try 265/30s, and if none of that solves it, I would unfortunately have to remove the wheels entirely. It rains alot in the seattle area, and holes in the fender liners simply wont fly here if you expect the car to last.

[drwankel]

Originally Posted by M43S7RO

I had rub at rear liners only up front on 19" 275/30 ad08r at full lock. I was -2 camber. My solution was not make full lock turns. Given my experience, i dont think adding camber is gonna help.

I imagine you are also rubbing at front is because the ps4s are prob bigger than ad08r.

I now run 285/30 re71 up front on 18" wheels with no rub, same camber (smaller total diameter).

Useful information- thanks for the input. What was the ride height when you were running the 275/30/19s? Stock, zcp, dropped? Did you ever try a 265/30/19? The more I read, ot seems the PS4S tires do seem to run larger than others, and I think this is definitely a piece of the problem.

I would suspect there would be a difference in fender lining rub pattern if you added camber while being dropped vs adding camber at stock ride height as well. (granted my car is a ZCP car, so it is a bit lower than others from the factory)

[M43S7RO]

Originally Posted by drwankel

Useful information- thanks for the input. What was the ride height when you were running the 275/30/19s? Stock, zcp, dropped? Did you ever try a 265/30/19? The more I read, ot seems the PS4S tires do seem to run larger than others, and I think this is definitely a piece of the problem.

I would suspect there would be a difference in fender lining rub pattern if you added camber while being dropped vs adding camber at stock ride height as well. (granted my car is a ZCP car, so it is a bit lower than others from the factory)

I was lowered a bit, not a lot, just closed the gap up front to about 1 to 1.5 inches. Didnt try the bigger tires before lowering and adding camber so cant add data there. I never tried 265/30. I did run 255/35 ad07r before moving to 275/30. No issues with the 255 from what I recall, been a while.

I agree that PS tires run big, i had 295/30r19s in back and they are much wider than the 295/30r18 toyo r888r that I run now.

[drwankel]

Updates. Switched some 265/30/19 PS4S tires in the front and it looks like they do not rub.

I suspect the wider shoulders of the PS4S tires was to blame here. Hopefully this information helps out someone in the future if they pursue a similar setup.

I will update this thread if I notice any issues.

Have not touched alignment yet- but will get the car aligned soon to ensure everything is as it should be.