[Weeknd]

Hi
i own a M235i
im thinking of changing the back tires from 245 to 255 wide
did anyone do it?
what are the advantages ?
what do u recommend?

[XutvJet]

FYI, 255s technically don't fit the OEM 8 inch wide rims.

[B58togo]

I did it, but I have 18x9.5" wheels. Wouldn't personally do it on the 8" OEM wheels. I will say the 255 PSS is markedly wider than the 245; closer to 20mm wider, rather than the 10mm you'd expect. Gonna try 265's next year.

[emtrey]

if tires are too wide for wheels, sidewalls will flex more and make handling worse. Only go to wider tires with appropriate width wheel.

[Zwei]

If you do get wider wheels don't stop at 255, 265's fit with no spacers required.

[CP911]

I went from the stock PSS to 255 rear/235 front PS4S on 19" rims. Ride quality, grip in both dry and damp road conditions (did not try full wet roads), and road noise were all improved for sure with the new setup. I know a lot of that could be from the improved PS4S tire compound, but I actually believe putting more rubber on the ground as well provides that much more suspension between you and the ground and therefore a more supple feeling ride.

Btw, I wouldn't go more than 255, personally. 265 is probably past the point of diminishing returns for a car of this weight and HP if we're mainly talking street use. My 255s poked a bit more than I was hoping for even though function was perfect with no rubbing or issues and the wheel offset was almost ideal for this car. I imagine fitting 265 in the rear would be difficult unless you like the ultra-poke look.

[Zwei]

My 265's in the rear are no pokier than my 235's in the front.



Onto the subject of ride. Increasing the wheel diameter shortens the sidewall which makes it less compliant. It also decreases the volume of air in the tire which makes it less compliant (you could go to a lower pressure but that will put your rim at more risk). For both reasons if you want a better ride quality you want to stay on your 18's.

No doubt 19's have the look. On smooth roads their tires will squirm less and grip better. On not so smooth roads their lower compliance will not grip as well.

There is no better or worse, just compromises and likes.

[B58togo]

Originally Posted by CP911

I went from the stock PSS to 255 rear/235 front PS4S on 19" rims. Ride quality, grip in both dry and damp road conditions (did not try full wet roads), and road noise were all improved for sure with the new setup. I know a lot of that could be from the improved PS4S tire compound, but I actually believe putting more rubber on the ground as well provides that much more suspension between you and the ground and therefore a more supple feeling ride.

Btw, I wouldn't go more than 255, personally. 265 is probably past the point of diminishing returns for a car of this weight and HP if we're mainly talking street use. My 255s poked a bit more than I was hoping for even though function was perfect with no rubbing or issues and the wheel offset was almost ideal for this car. I imagine fitting 265 in the rear would be difficult unless you like the ultra-poke look.

My PSS 255's are still tucked with 5mm spacers on 9.5" et58's. Wheel offset is really what dictates poke. I'll barely be flush with 265's. More worried about strut clearance than fender issues.

[CP911]

Originally Posted by B58togo

My PSS 255's are still tucked with 5mm spacers on 9.5" et58's. Wheel offset is really what dictates poke. I'll barely be flush with 265's. More worried about strut clearance than fender issues.

Your spacer brings you back down to an offset of et53 (stock rear is et52) and then you are 1.5" wider at the rim compared to stock. So I calculate ~18mm of poke. I was at 21mm of poke and outside edge of protective tire bead on PS4S tires was exactly flush with top of rear wheel arch. So yes, yours are probably as aggressive as I'd go without starting to look too pokey, which I felt mine were on the verge of being too much at only 3mm more poke than yours. Nevermind the poke though - I'm honestly more surprised there is enough inboard clearance with your setup even with the more stretched 255s. 265 rear still seems like trouble to me unless someone can show me a setup that exists where there is ~20mm or less poke and at the same time no inboard rubbing. Talking stock suspension and no fender rolling here.

[Zwei]

If anyone cares, I'm on 58 offset, no spacers and 265 PS4's. No mods to fenders or struts and no issues. I too was concerned about rubbing but my wheel source sent me a convincing picture of a similar setup.

The square 225 All Season runflats are now the cold weather wheelset.

[CP911]

Originally Posted by Zwei

If anyone cares, I'm on 58 offset, no spacers and 265 PS4's. No mods to fenders or struts and no issues. I too was concerned about rubbing but my wheel source sent me a convincing picture of a similar setup.

The square 225 All Season runflats are now the cold weather wheelset.

Interesting. What are wheel specs?

[Denk]

I really like a 255 on a 9" wide rim in the back on this car. Looks and feel improved. et 48-50 would be nice. My BBS CHR's are 9", et44 in the back and I had 255's on them. The wheel is totally flush with the fender but the tire does poke a little as CP911 has mentioned. I put 245's on and no more poke, all is flush and looks better to me. I'd run 255's if these BBS's were at least et48. No experience with 265's on this car but totally doable with proper offsets in regards to wheel width.

[RotorOver]

I'm on Dinan springs/bump stops, 18x9 et 50 rear running MPS4S in 265 with no poke and no rubbing.

[Zwei]

Originally Posted by CP911

Interesting. What are wheel specs?

This is from the email with my wheel source:

"I would be glad to put together a package for you. The wheel selection sizes you have are semi correct but I would go with a different size. I would do a 18x8.5 et 45 and 18x9.5 et 58. That size will allow you to run a 265 rear with no rubbing."

The wheels are Apex EC-7's. Roads are bad where I live so 18's are the only choice.

Once mounted I realized that I was going to have to determine what tire pressures to run. 33 up front was good. More bounced, less was squirmy. In the back I tried 38, 33 and then settled on 35. 38 was too much for potholes. 33 wouldn't let the back end move out on turns.

[BarryB]

245/265 fits perfect. 5mm spacer in the rear. I have a thread on this.