[Dr Thrillride]

Gentlemen,

What a fiasco with the stock Bridgestone Potenzas on the M850i.

Literally 2500 km on car, wife drives from Kelowna to Calgary (750 km), first time she's driven it...leaky tire...limps to dealer, dealer says tires are temperature abused and cracked and shouldn't be driven on the Hwy...wtf? whatever, how to get her back in the car?

Michelin PS4s four days out, wife needs to leave Calgary, we put winters on...end that story.

BMW Canada comes back and says they'll pay for 3 of the 4 tires...I'll take it...

Now have to pick size...

Given the allowances, in terms of size, may be different from M850 to M8 (otherwise, I defer to you knowledgeable folks), what is the widest you folks have gone? Can't find much using search option.

I will keep the winters on the stock rims. Had the Vertini VS1.1s on the M6 and loved them...different bolt pattern has me selling them and buying a new set, so wheels aren't limiting factor. Don't want a bolt pattern adapter.

Any ideas folks? Thanks in advance!

Doc

[LSM]

Your car is awd you need to keep the overall diameters close to same front and back as they were stock

That may not answer your question exactly but you cannot simply get a wider rear without adhering to overall diameter for front and rear

[Dr Thrillride]

Originally Posted by LSM

Your car is awd you need to keep the overall diameters close to same front and back as they were stock

That may not answer your question exactly but you cannot simply get a wider rear without adhering to overall diameter for front and rear

yes definitely got that much. Thanks for checking...

[FBMWWINS]

With M8 wheels on the 850i the rear wheels would stick further out by some 4 cm and 3cm in the front. Also on the rear you would have a positive scrub radius of some 6mm. Not sure what the tolerance is but some say it could affect handling. Not so easy I would say - technically they should fit but the question remains - is it a"driveable" setup especially considering the xDrive part?

Here you could do some tire/wheels calculations yourself:

https://www.wheel-size.com/calc/

[Dr Thrillride]

[RJC-1]

Stick with stock sizes or it may blow your warranty...

[Dr Thrillride]

Originally Posted by RJC-1

Stick with stock sizes or it may blow your warranty...

Great advice for newbs, which I am not. Seems another newb gave the same advice above

[Superjackson]

With the correct offsets, you can most likely use the stock m8 tire sizes of 275/35/20 285/35/20. The rear offset definitely must be higher than m8 but the front should be almost the same offset, you'd have to do measurements to make sure tho.

[Dr Thrillride]

went with:

Front: 245/30/20 9/35
Rear: 285/25/20 10.5/45

All good, no issues.