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[Notwithstanding]

Having just failed an MOT on 2 cracked rear 313M's, thanks no doubt to the run flats but also the tiny profile of the tyres on UK roads, I'm wanting to protect the replacement ones as much as possible. It's been expensive to say the least.

Firstly, I'm definitely going non-RFT, Michelin PS4 ideally but I was thinking of also going up one profile increment on front and rear, do you think it would cause issue?

As tyres decrease approx 12mm in diameter over their life from 8mm to 2mm, wheel circ is never a constant thing, so tolerance wise (I know the speedo will read low), would an E92 m-sport accept

Front: From 225/35/19 to 225/40/19
Rear: From 255/30/19 to 255/35/19

tyre calculators show that the sidewall increases of 1/2", so an inch overall to diameter and a 3% increase in speed.

If it would cause rubbing or bottoming out I'll stick to current sizes and just go non-rft, but just want to do everything possible to stop these wheels cracking again.

I see E92 M3 wheels have not only a staggered setup, but taller wheels on the back (245/35 front, 265/35 rear), I might just do the same, as its the rears what are cracking

[Josh_G]

Originally Posted by Notwithstanding

Having just failed an MOT on 2 cracked rear 313M's, thanks no doubt to the run flats but also the tiny profile of the tyres on UK roads, I'm wanting to protect the replacement ones as much as possible. It's been expensive to say the least.

Firstly, I'm definitely going non-RFT, Michelin PS4 ideally but I was thinking of also going up one profile increment on front and rear, do you think it would cause issue?

As tyres decrease approx 12mm in diameter over their life from 8mm to 2mm, wheel circ is never a constant thing, so tolerance wise (I know the speedo will read low), would an E92 m-sport accept

Front: From 225/35/19 to 225/40/19
Rear: From 255/30/19 to 255/35/19

tyre calculators show that the sidewall increases of 1/2", so an inch overall to diameter and a 3% increase in speed.

If it would cause rubbing or bottoming out I'll stick to current sizes and just go non-rft, but just want to do everything possible to stop these wheels cracking again.

I see E92 M3 wheels have not only a staggered setup, but taller wheels on the back (245/35 front, 265/35 rear), I might just do the same, as its the rears what are cracking

i have changed to higher profile on the rear nonRF and the ride feels soooo much better, not done the front yet as i still have plenty of tread left. once the fronts wear down they will go nonRF and higher profile as the roads in Surrey are appalling! No rubbing on the rear with MV4s and MSport suspension.

[Andy198712]

and that was just going up 5 on the profile?

[Josh_G]

Originally Posted by Andy198712

and that was just going up 5 on the profile?

correct, it doesnt look as nice.. but it feels a lot better

[Notwithstanding]

Originally Posted by Josh_G

i have changed to higher profile on the rear nonRF and the ride feels soooo much better, not done the front yet as i still have plenty of tread left. once the fronts wear down they will go nonRF and higher profile as the roads in Surrey are appalling! No rubbing on the rear with MV4s and MSport suspension.

brilliant to hear, thanks. I'll be doing the same to the fronts too but am concerned with lock to lock rubbing. by the way, do you find the rears wear the inside shoulders quicker than the rest of the tyre?

[Josh_G]

Originally Posted by Notwithstanding

brilliant to hear, thanks. I'll be doing the same to the fronts too but am concerned with lock to lock rubbing. by the way, do you find the rears wear the inside shoulders quicker than the rest of the tyre?

on the new or the old RF? i noticed on the RF it was slightly more worn on the inside but not that bad at all realy.

[Notwithstanding]

Originally Posted by Josh_G

on the new or the old RF? i noticed on the RF it was slightly more worn on the inside but not that bad at all realy.

it's happened on 2 sets of potenzas, I also think the aggressive negative camber focuses a lot of the weight of the car onto the inner edge, just not a good thing, I'll be dialing out a bit of that negative camber to regain some balanced wear patterns.

[Notwithstanding]

Getting the higher profile tyres fitted today but I hope they don't cause any issues. I've gone for PSS which I know are quite a chunky tyre to begin with compared. Will just have to see, hopefully no rubbing. They're the same tyre widths as stock, just up 5 on both profiles

[rothwem]

Just FYI, the M3s have bigger fenders so they can fit more tire.

With that said, I'm running 245/45/17s, which are about 3/4" taller than stock with no problems. I'm not sure I'd want to go much bigger though.

[Notwithstanding]

Originally Posted by rothwem

Just FYI, the M3s have bigger fenders so they can fit more tire.

With that said, I'm running 245/45/17s, which are about 3/4" taller than stock with no problems. I'm not sure I'd want to go much bigger though.

Thanks, I've had them fit and so far no rubbing, but my main concern would be the taller tyre on the front when a large steering angle is combined with suspension compressing such as a small roundabout at speed, or the wheel coming down from a curb when on full lock. In that situation the tyre runs across the arch and when the car is stood still, on full lock, three only around an inch of suspension travel till they would collide