New F30 owner question

[Elliott1986]

Hi everyone,

New to xdrive, my current car is a 320i xdrive step auto. Had an E90 before this.

My car cane with Pirellis on the front and Bridgestones on the rear. Is this ok for the xdrive system?

Car has been stick at BMW for 2 weeks now for a problem not related to the transmission. Really miss driving the thing, on my second 1 series courtesy car.

[X5Sport]

Both brands are available as ‘*’ marked so as long as they have the mark that’s one less worry.

Do you have the same size all round, or different on each axle?  Less of an issue with needing ‘*’ marked tyres on ‘square’ set up wheels than on staggered, and as long as the tread depth is roughly the same front and rear then you are probably fine.

The real problems seem to occur with wide tread depth differences and staggered wheel setups.  It doesn’t affect everyone, and there are no definite no no’s other than avoiding ‘agricultural’ off road tread patterns or budget brands.

If the car has any odd noises from the transmission or jerkiness at low speeds on full lock then you need to worry.  If not then you don’t. 

Oh and to the Forum. 

[Elliott1986]

Thank you.

Off the top of my head they are equal or within 1% but with the car being stuck at BMW I can't even remember the sizes.

No abnormal noises or jerkiness at all. But haven't owned the car 5 minutes really, only done around 1000 miles in it.

[X5Sport]

Anticipation will make it all worth it 

[Elliott1986]

I have x4 winter tyres that I used on my E90. All the same tyre size etc.

With this 'square' setup do the tyres need to be star rated too?

Sorry for all the questions. Trying to learn about xdrive system

[X5Sport]

It’s less likely to be an issue. 

The problem is due to the different tyre sizes produced by some brands having widely different diameters meaning one tyre size has a larger circumference than the other so going further with each revolution.  This winds the transmission up and in the worst case, breaks it.  ‘*’ tyres are matched across the relevant sizes to ensure that the circumferences on new tyres are the same.

In all cases you need to keep the tread depths very similar.