[Aufwuchs]

I bought a CPO 2015 M235i last week. Just noticed that the new tires installed by the dealer are 225/45 rather than the specified 225/40. They are the Pirelli run flats. Any reason to be concerned or raise the issue with the dealership? I absolutely love the car so far. Thanks!

[hwntime]

Originally Posted by Aufwuchs

I bought a CPO 2015 M235i last week. Just noticed that the new tires installed by the dealer are 225/45 rather than the specified 225/40. They are the Pirelli run flats. Any reason to be concerned or raise the issue with the dealership? I absolutely love the car so far. Thanks!

The overall diameter of the 45's will be slightly taller than the 40's.

225/40 = 25.09"
225/45 = 25.97"

So there is a 0.89" difference in height equaling 3.5% unless the dealer recalibrated your speedo which I doubt. If you're driving 60mph, your actual speed with the taller tire will be 62.12mph. No concern really.

[Aufwuchs]

Originally Posted by hwntime

The overall diameter of the 45's will be slightly taller than the 40's.

225/40 = 25.09"
225/45 = 25.97"

So there is a 0.89" difference in height equaling 3.5% unless the dealer recalibrated your speedo which I doubt. If you're driving 60mph, your actual speed with the taller tire will be 62.12mph. No concern really.

Thank you! Maybe it will provide extra cushion for our notorious potholes.

[aerobod]

Originally Posted by hwntime

The overall diameter of the 45's will be slightly taller than the 40's.

225/40 = 25.09"
225/45 = 25.97"

So there is a 0.89" difference in height equaling 3.5% unless the dealer recalibrated your speedo which I doubt. If you're driving 60mph, your actual speed with the taller tire will be 62.12mph. No concern really.

On my M240i, the GPS verified stock 245/35-18 rear tyres are 4% high reading at 100km/h (speedometer reads 104km/h), 225/45-18 winter tyres are a lot closer to accurate, reading 1% low at 100km/h (speedometer shows 99km/h).

[Aufwuchs]

Explains why I’ve been passing everyone since I got this car. Speedometer is off. ;-)

[Maynard]

I thought all our speedos read about 3-4% high in stock form, so this would just bring you up to accurate? Or have I just been deluding myself that I have a few extra mph of safety margin for the radar gun?

[skievl23]

Originally Posted by Aufwuchs

I bought a CPO 2015 M235i last week. Just noticed that the new tires installed by the dealer are 225/45 rather than the specified 225/40. They are the Pirelli run flats. Any reason to be concerned or raise the issue with the dealership? I absolutely love the car so far. Thanks!

Odd question but I have a 228i m sport THP that i just bought winters for, and was curious if the 225/45/18's fit well??

[aerobod]

I run 225/45-18 Sottozero 3 winter tyres on our M240i on 18x8 ET45 OZ Omnia wheels, no rubbing at all.

[skievl23]

Originally Posted by aerobod

I run 225/45-18 Sottozero 3 winter tyres on our M240i on 18x8 ET45 OZ Omnia wheels, no rubbing at all.

they didnt fit my car because its ET30 offset lmao