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[JimD]

My 2009 128i cabrio is one of two vehicles I drive so it just got 4 new tires - mileage was about 24,400 and rears were at the wear bars. I went with Michelon Pilot Super Sports in 225/45/zr17 all the way around. I've only driven them a couple miles home so far but the ride seemed to be a little better. My car has the sport package - you had to get it in 2009 to get 17 inch wheels. I'll try and add something when I've driven them more and have a better feel for the ride.

My front wheels are 0.5 inch narrower than my rears and you can see the sidewall bulge a very little bit on the fronts but I think it looks good. The place I got them gave me a price lower than tire rack's so I was out the door for about $850 (tire rack was $782 with shipping but without mounting or balancing). They provide free rotation but said they wouldn't do front to back. I guess I'll have to do that myself. I don't know why they didn't want to go front to back but I tend to do things myself anyway.

I carry a compressor and may get a plugging kit. I've gotten very few flats over the years so I'm not real worried.

Besides rotation the reason I went square is to reduce understeer. I'll need an autocross session to get a good handle on that.

Jim

[bmw1racer]

Congrats... I'll most likely go square when I'm due for new rubber as well.

Hmm, maybe they won't rotate front to back because the front wheels are 0.5" narrower than the rears....?

[JimD]

My guess is they think the offsets are different. But I looked them up and they are the same.

My car will be past it's warranty next summer before I get 5K miles on the new tires. I was already thinking of changing oil at 5K intervals. I know it's quick but that's about 9 months for me and it's easy to remember. Maybe my routine will be to just put it on stands all around and rotate the tires at the same time. I already have to lift one end for the oil. I could rotate the tires while waiting for the oil to drain.

Jim

[JimD]

I have a hundred miles or more on my tires now and wanted to comment that the ride had definitely improved and I like the feel of the new tires a lot. I don't consider the ride difference a night and day difference but it is better. It seems more like the difference between the sport and non-sport suspension. My girlfriends 128i has the non-sport suspension and mine has the sport. Her's is new with run flats and seems to ride about like mine now. I am still looking forward to trying my new tires out in an autocross.

Jim

[bmw1racer]

^ Nice... The Michelins will definitely be on my short list.

[Kim Schwartz]

Originally Posted by JimD

My guess is they think the offsets are different. But I looked them up and they are the same.

My car will be past it's warranty next summer before I get 5K miles on the new tires. I was already thinking of changing oil at 5K intervals. I know it's quick but that's about 9 months for me and it's easy to remember. Maybe my routine will be to just put it on stands all around and rotate the tires at the same time. I already have to lift one end for the oil. I could rotate the tires while waiting for the oil to drain.

Jim

The offsets are the same but the wheel widths are different. I remember17"x 7" front and 17"x 7.5" rear with the sport suspension. I have the same and went to a square setup and also prefer it. I got different wheels that are also the same in each corner.

[bmw1racer]

Here's a question: Since you went square, did you maintain the same recommended F/R tire pressures of 32/35 or switch to something different?

[bozola]

I got these tires as well (Although staggered) and for me , the difference between those and the original NCT's was night and day.

My only complaint is that 30k and the rears are gone.

But now.. I am thinking of doing what you did... but maybe with Conti DWS's...

[JimD]

I run a little over stock pressure. I did with the stock RFTs too. During an autocross I run 40psi cold.

[SteveAZ]

I just switched from a 17" square RFT setup to these in 18s, a little smoother even with the bigger wheels. The weight loss was huge...46#s of sprung weight. I don't feel near as much of a "thud" when I hit a bump in the road...wife also noticed that right away as there is a set of traintracks we cross regularily. Haven't had a chance to see if they understeer more in the corners yet. Hoping they'll hook up a bit better and give good feedback in the corners. I'm running 40F/42R

[bmw1racer]

Originally Posted by JimD

I run a little over stock pressure. I did with the stock RFTs too.

Any advantage in doing that?

[SteveAZ]

Originally Posted by bmw1racer

Any advantage in doing that?

For me, I was having problems with traction and was told to look at my tire marks. If they were a couple of lines (inner and outer edges of tire) to increase tire pressure so there was a better contact patch.

[simianspeedster]

I'm piggybacking on this thread because it's directly on point with my question.

I'm very likely to order a 128i in a couple months and, if BMW allows the combination of M-Sport and the upcoming 1 Series Lifestyle Edition (hate the name of that package but love the brown leather), the car will likely come with 18x7 fronts and 18x7.5 rears. I'd plan to ditch the runflats right off the bat and go square (225/40-18 all around).

Is there any problem/risk/disadvantage with the difference in wheel width or is it largely immaterial with that tire size?

Thanks in advance!