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[asbrr]

Greetings all,

After getting a headache reading all the threads on tire fit and wheel combos, I only found a couple of people using the above mentioned setup for tire size. I realize the fronts will be taller by 2%, is there any downside with respect to DTC, TPMS, ABS or any other car systems?

The car is a 128i coupe running factory sport suspension and style 263 wheels. I am hoping to expand my tire selection by eliminating the weird factory front size. I have the Michelin pss as a fall back, but may consider re760s if I go with this sizing to save a bit of cash.

Also, would like the added benefits of less understeer with a more neutral setup.

Any thoughts on this? Appreciate the help.

Thanks in advance
Ash

[E82MSport]

I posted this about 4 posts down from yours. I assume these are the same factory sizes you have.

Food for thought when looking at tire sizes. I would recommend staying as close to OE overall diameter as possible, as it will give you less issues with rubbing. Tire width on the other hand is a bit more forgiving (given offset is reasonable) but on the 1-series it's still limited.

08' 128i stock with Sport Package - 205/50/17, 225/24/17 Bridgestone Potenza RE050A I RFT

205/50 = 25.1" overall diameter
225/45 = 25" overall diameter


Both the Michelin PSS and the Bridgestone RE760 in a 225/45/18 are 25.1" overall diameter.
http://www.tirerack.com/tires/tires....SSXL&tab=Specs
http://www.tirerack.com/tires/tires....60XL&tab=Sizes

The extra width up front will help with understeer but if you can max out your negative camber that will also help with turn-in. I'd imagine you can get about -.75-1.0 by pulling/drilling the alignment pins on the factory top mounts. If you go this route I suggest getting an alignment after, as camber effects toe. And in the case of our vehicles, more negative camber will cause toe out.

A 245/35/18 available in the RE760's and MPSS and the overall diameter is 24.8". The 2 tenths will not be an issue. If you want confirmation I would contact our Forum Sponsor TireRack.

[asbrr]

Thanks.

Actually, the car has the 18" style 263 wheels from the factory - that's how they came here in Canada when equipped with the sport package. So that means 215/40/18 up front, and 245/35/18 at the back.

So I was hoping to just replace the fronts with 225/40/18. I've been going through the various tire options, and in the RE760 the 225/40/18 is a 25.1" diameter, the rears in 245/35/18 are 24.8". Compared to the stock bridgestone RE050 RFT in the 215/40/18 front with 245/40/18 rear, those are 24.8" front and 25"

Basically I'm swapping that around - the RE760s will be .3" taller at the front than the rear.

That's what I'm really asking about, is 0.3" difference significant for any of the car's systems? I figured not since in OEM size the front is actually 0.2" shorter than the rear!

Thoughts? Thanks
Ash

[John_01]

The new BMWs such as F20 and F22 come with 225/40/18 front with 245/35/18 rear tire combination as a factory option.
There is nothing wrong with having 0.2" difference in diameter between front and rear. You won't be able to notice it visually.

[FactorX81]

I have a set of 225/40 R18 PSS in front with no issues to speak of.

[asbrr]

Alright, that's what I figured.

Thanks folks, I will likely go with a 225/40/18 front and 245/35/18 rear.

[BMWX1-35i]

I'm using 225/40's up front and 265/35's in the rear.

[weeeee]

I am installing 225/40/18 and 245/35/18 Continental ExtremeContact DW on 261m rims with m sport suspension tomorrow, I'll let you know how it goes, wasn't expecting any issues.

[Solo_M_Tech]

If tire height is a concern get 245/40-18 MPSS.

[weeeee]

Originally Posted by weeeee

I am installing 225/40/18 and 245/35/18 Continental ExtremeContact DW on 261m rims with m sport suspension tomorrow, I'll let you know how it goes, wasn't expecting any issues.

All is well

[asbrr]

Thx!