[njdan]

I have a 2010 328i xdrive coupe running 235/40/18 kumho tires, I need to get new tires and I was wondering if I would be able to run either 235/45/18 or 225/45/18 without any problems. Stock OEM is 225/45/17 I am looking to get a little more rubber to deal with the crappy roads after this winter.

[Nossic]

If you want more rubber, stick with 17s, or it will throw the speedo, and mileage counter off. But... There are people who fit 19s on their car, which are bigger than the stock sizes and thus throwing the speedo off. But with that said, I guess those could work.

I'd personally rather stay on the safe side with 17s. (cheaper tires and wheels)

[njdan]

I already have VMR V710 18x8.5 ET35 5x120 72.6 Hyper Silver just want to make the ride better for everyday driving. the roads here are crap.

[dpaul]

I have 225/40-19 and 255/35-19 Conti DW mounted on BMW 230 wheels. The diameter of my setup is the same as the 225/45-18 that you are contemplating, which is ~1" greater than E9x stock (but equal to the diameter of the tires fitted to the F30s 3 series). There is no rubbing whatsoever at full lock and I've had no indication of any rubbing at speed over bumps.

Thus, the ride height is increased about 0.5". Now I don't scrape on every driveway entrance and speed bump. Nossic is wrong about the speedometer, which now reads correctly. BMW set it to be 5% high to insure their cars will always meet TUV (there are many threads on this issue).

The tires more fully fill the wheel wells and look better to my eye (sorry I don't have a picture to post right now). The ride is slightly more comfortable than the 225/40-18 square setup I ran previously. However, the big improvement in ride came from replacing the stock structs with Koni FSB - if you have stock suspension I would urge you to consider some type of upgrade.

One downside of increasing diameter is a negative impact on acceleration (i.e. you've changed the gearing slightly). I don't notice it in everyday driving with my 335xi but it might be more of a factor with the 328.

[njdan]

Thanks, for the input. I saw a 328i today at the dealer and it had 255/35/18 rear and 225/40/18 up front

[njdan]

Could I run 255/35/18 on 8.5 inch rims?

[dpaul]

Yes - that is an E9X standard wheel width/tire size combination. Allowed widths for that tire 8-9.5" for most manufacturers. 8.5" is the design width for that tire

[njdan]

trying to decide on running what I saw today or just getting 225/45/18 all around

[ludwigkarl]

I changed from staggered 17" on my 2010 e91 xdrive touring to OE 18" (Type 193) with OE tires (PS2) 225/40/18 front & 255/35/18 rear. The tires were not new but still OK. However, when I changed to my winter tires this season after about 10K Kms, I found the rears had worn down to the steel mesh on the inside?? I was not sure if there was a problem due to the wheel size or offset when it came to cars with xdrive?? I know the 18's were an option on non xdrive models (I owned one in 2007 -pre LCi) but I'm not sure about xdrive models???

[dpaul]

I know that 18" staggered was an option on pre- and post-LCI 335 xdrive E90/92/93 and that 193 wheels have the standard offsets (34 and 37mm fr/rear) recommended by the factory for 225/40 and 255/35 tires. I don't know of any reason why the 328. xdrive or not, should be any different. I wonder if the problem might be a different geometry in the E91?

[equ]

You cannot run 235/45-18 or 225/45-18, those are simply too tall for the design spec of this car.

[dpaul]

It is not the design spec but it works perfectly well and there are some advantages

[ludwigkarl]

Like I said, in Germany I had a pre LCi e91 that I ordered new with the optional 18" staggered wheels. However, it was not an xdrive. I also ready somewhere around here that the LCI has different geometry on the rear? Is that true?? The dealer said it would not be an issue but I should get an alignment done.

[dpaul]

My understanding is the LCI has a wider track but only by a few millimeters and that the rear suspension/drive is identical (except for shock valving and spring rates) in E90/92/93 AWD and RWD vehicles. It is hard to believe that OEM toe/camber settings could be different enough between models to account for the wear you experience. Perhaps your rear camber setting is for some reason way,way off - the suggestion to at least have the alignment checked is a good one just to rule out that possibility.

[aadum]

Originally Posted by ludwigkarl

I changed from staggered 17" on my 2010 e91 xdrive touring to OE 18" (Type 193) with OE tires (PS2) 225/40/18 front & 255/35/18 rear. The tires were not new but still OK. However, when I changed to my winter tires this season after about 10K Kms, I found the rears had worn down to the steel mesh on the inside?? I was not sure if there was a problem due to the wheel size or offset when it came to cars with xdrive?? I know the 18's were an option on non xdrive models (I owned one in 2007 -pre LCi) but I'm not sure about xdrive models???

check your camber. It should be set to - 0.55 if I am not wrong.
If you really want you could put it to something like -2.5 degrees but that would still not eat your tires quick as it happened to you