[bmwr]

I am thinking about purchasing winter wheels/tires my summer wheels/tires are stock which are 19 x 8.5 and 245/45 R19 run flat all season. Would this set work 18 x 8 and 235/55 R18 run flat? Will this cause any issues with the vehicle warranty?

[Pinewood]

245/45/19=703mm Most tyre specialist advise deviating from this by +/- 2% as an absolute maximum.
235/55/18=716mm so i would say no, as a difference of 13mm will alter the speed and gearing, it may also foul on the cars undercarriage.
The only way you will know for sure is mounting them on the car and going for a test drive

[nyalpine90]

245/50/18

tirerack!

[malicem3]

I would also recommend using Tirerack.

On another note, you can go down to 17's.

[brissim]

Originally Posted by Pinewood

245/45/19=703mm Most tyre specialist advise deviating from this by +/- 2% as an absolute maximum.
235/55/18=716mm so i would say no, as a difference of 13mm will alter the speed and gearing, it may also foul on the cars undercarriage.
The only way you will know for sure is mounting them on the car and going for a test drive

I've been running similarly oversized tyres for 5 years and 110,000km without any issue. In my case its with 17" wheels where the OEM tyre size was 245/55/17 (701mm) and the replacement tyres have been 235/60/17 (714mm) - ie a similar difference of 13mm.

Yes it puts out both the odometer and speedo by nearly 2% - ie when indicating 100km/h I'm actually doing 102km/h (60mph/61.2mph). So just be aware of this around speed cameras.

Most importantly this does not break our local Australian laws where we are allowed up to a -26mm/+15mm variance from OEM tyre size. Therefore the car remains legally roadworthy and does not impact on either your car insurance or BMW warranty - again at least in Australia. Suggest you at least check what your local laws are.

Alternatively as suggested above, 245/50/18 is an OEM tyre size almost identical in overall diameter to your existing 19" tyres.

Tony

[bmwr]

I am only deviating +1.8%. There are more tire options available with 235/55/18 vs 245/50/18

[malicem3]

I am running 245/55/17 with no issues. I'd imagine that a slightly larger wheel wouldn't make too big of a difference. I opted for that tire because of options as well.