[pacificsky]

Hi,

Will I have any issues if I mount 225/40/18 (Michelin Alpin PA4) tires on the OEM rear wheels (which are 18x8) on a RWD M235i?

The staggered fitment of the OEM tires/wheels means that the winter tire choices are quite limited for the rear wheels. But according to http://www.tyresizecalculator.com/ty...dth-calculator I should be able to mount 225/40/18 tires on the rear wheels as well (so I'll have staggered wheels but identical tires across all 4 wheels). Note that this is only for winter tires, I'll continue to use staggered tires for spring/summer/fall.

I could get a separate winter tire + wheel set, but honestly I dislike the OEM wheels so I'm hoping to get a separate set of wheels for the Michelin PSS summer tires come spring, and use the OEM wheels as part of my winter set.

Thanks for your help!

[CanadianGatorBacon]

Rim width range for the 225/40/18 Michelin Alpin PA4 is 7.5-9"

[pacificsky]

Right, so it sounds like the 225/40/18 tire will fit fine on the OEM rear wheels. Is there any concern from a traction/handling/safety perspective given these are slightly narrower tires? And should I consider 245/40/18 instead of the 225/40/18 instead? (a wider tire, about the limit for the 18x8 OEM wheels).

[CanadianGatorBacon]

It will fit. 8" is actually considered the "right" size rim for a 225/40 tire. For a real winter tire that you're driving in the snow, usually narrower is better for cutting through the snow rather than floating over it. If you aren't driving in the snow, then you could go wider, but there is nothing wrong with a 225/40 square setup. BMW offers it for their all season tire option, though they supposedly restrict top speed for the all seasons (but that's because of a confluence of factors). You'll have a smaller contact patch with the 225s, but if you're not pushing the car, you shouldn't have an issue. You'll likely feel more planted with a wider tire, but then you're getting into personal preferences.

[shark715]

Originally Posted by pacificsky

Hi,

Will I have any issues if I mount 225/40/18 (Michelin Alpin PA4) tires on the OEM rear wheels (which are 18x8) on a RWD M235i?

The staggered fitment of the OEM tires/wheels means that the winter tire choices are quite limited for the rear wheels. But according to http://www.tyresizecalculator.com/ty...dth-calculator I should be able to mount 225/40/18 tires on the rear wheels as well (so I'll have staggered wheels but identical tires across all 4 wheels). Note that this is only for winter tires, I'll continue to use staggered tires for spring/summer/fall.

I could get a separate winter tire + wheel set, but honestly I dislike the OEM wheels so I'm hoping to get a separate set of wheels for the Michelin PSS summer tires come spring, and use the OEM wheels as part of my winter set.

Thanks for your help!

I did the same installation that you are contemplating just a couple days ago, and I even have xdrive and there are no issues.

I do have to say though, that I'm somewhat disappointed in the PA4 tires. I find that they have an unexpectedly vague on center feel. I've tried significant changes to the tire pressure, and it does not resolve the issue. I have had winter tires on plenty of other vehicles before, and have never experienced this.

It might just be that the super sport tires that I just took off the car are just so good, that is highlighting the difference, rather than there being any issue with the PA4's. I have the super sports on other cars also, and I think they are the best tire that I've ever owned...not exaggerating.

[esoulliard]

FWIW, I just had my staggered summer tires replaced with a square 225/40/18 winter tire setup on the stock wheels today. I was even able to get my dealer to mount the tires. They recommended going with a staggered setup, but I agree with what CanadianGatorBacon said about having narrower tires for the white stuff. I was also able to supply my own tires. Good luck.

[DanG]

I have four 18 X 8 wheels and I am running the stock staggered tires. As our Candian friend said, 225/40/18 is the optimum size for an 8 inch rim. When my rears wear out, I will mount 225/40/18s all the way around.

[Prazision]

i have 225 all around on staggered stock wheels. you're fine.

[TBURKE555]

I just did this 225/40/18 PA 3's on stock rims. No problems

[pacificsky]

Thank you all for the great responses. Sounds like 225/40/18 will be just fine for my winter setup.

Though, I am curious if 245/40/18 will fit well on the rears (seems to be about the limit for 8" wide wheels)

[Saab Story]

Originally Posted by pacificsky

Thank you all for the great responses. Sounds like 225/40/18 will be just fine for my winter setup.

Though, I am curious if 245/40/18 will fit well on the rears (seems to be about the limit for 8" wide wheels)

I Mounted the exact setup you are referring to, 225/40/18 PA4's all around last week. No Issues mounting. It handles pretty well and the PA4's have a decent amount of grip. Although, the 225's make me feel like I'm driving a civic.

I am also thinking about picking up some 245/40/18s for the rears so I'm interested in hearing some feed back and seeing pictures of this setup on OEM Wheels. Is anyone running this setup with dinan springs?

[pacificsky]

To close the loop, I ended up with 225/40/18 PA4's all around on the stock OEM wheels. I ordered the tires from costco.com, had them shipped to a local Costco tire center and they took care of it quickly.

[shark715]

Originally Posted by pacificsky

To close the loop, I ended up with 225/40/18 PA4's all around on the stock OEM wheels. I ordered the tires from costco.com, had them shipped to a local Costco tire center and they took care of it quickly.

I first tried to buy the same exact same tires from our local Costco.

I special ordered the tires, but when they arrived and I brought my car in, they refused to install them as they were concerned about damaging the Xdrive system as they are not the OEM size with staggered wheels. They were very apologetic and said they should have asked me if I had Xdrive before they ordered the tires for me. Apparently each individual tire center manager has decision making authority as to what they will or will not install.

I ended up reordering the tires from Tire Rack (who knew I have Xdrive, but still filled the order after what they termed a "technical review" process), and had them installed by a local Tire Rack installer that I've used before...the total installed price was almost $100 less than Costco.

[pacificsky]

That's unfortunate. Glad you got a good deal overall.

[shark715]

While being careful exactly what he said, the Costco Tire center manager pretty much admitted he knew the tires would not be a problem, but that their concern was that if I had problems with the car (such as with xdrive or DSC) that BMW and/or myself might try to blame them for installing tires that are not OEM size versus the wheels on the car.

What's notable (as others here have pointed out) is that with staggered wheels the circumference of the OEM front tires are about 1.2% larger than the rears.

I wonder why that does not cause issues. One of my friends installed different size tires on the rear axle of his Boxster that were only about 1% larger versus OEM and it caused the DSC system to indicate a failure, although interestingly it did not happen until he had driven the car a few hundred miles, so it didn't occur to him that the problem was related to the tires.

His dealer spent several hours on labor (with repeated calls to Porsche) trying to analyze the issue before they realized it was the tires, and wanted to charge him for the labor costs...he eventually agreed to pay 50% of the bill.

[pacificsky]

Tolerances perhaps? Both the staggered sizes and the square 225/40/18 size are part of BMW oem equipment for this car (ie you can order the car with either)

[MyM235i]

I am doing the the same. The only thing to consider is now you cant rotate the tires if they are directional as you cant put the rear rims on the front. This just occurred to me looking at my new X-ice.

[pacificsky]

Same problem with the OEM stock tires too.

[MyM235i]

I don't believe the PSS are directional so you can swap left to right at least.