[peterwwillis]

You don't have to stick to the OEM tire. You can get a different, cheaper size, as long as it doesn't rub the wheel well or bottom out. And the exact tire and manufacturer you get, along with the conditions it was kept in, will determine the wear life of the tire. And when people complain about their tires wearing fast, it's often just badly aligned tires that could be fixed by going to a better mechanic. And buying tires online or from a warehouse is always cheaper, often by a lot.

So just because you have a certain kind of car doesn't mean you will always have the same tire wear or cost.

[gambiting]

>>You can get a different, cheaper size, as long as it doesn't rub the wheel well or bottom out.

In the UK you have to tell your insurer if you do that and it can impact your insurance significantly in some cases. The best one I could find was with Aviva they allow 10mm variation in width of the tyre from the manufacturer spec, so if the original size was 225/45 you could buy 235/45 or 215/45, but anything beyond that would require you telling them and have an impact on your premium. Chaging the rims to a different size always requires telling the insurer, even if they are the manufacturer's original rims(which is incredibly dumb, I bought my car with factory 20" wheels, I bought an original set of wheels directly from the dealership in 19" size but I still have to tell my insurer because it's a "modification" to the factory spec of the vehicle).

[peterwwillis]

Why would you tell your insurer? They don't go around checking tire widths, afaik

[gambiting]

Because if you have an accident and they find out you had tyres/rims different from stock they will absolutely either refuse to pay out the claim or reduce it significantly. Especially if you put on tyres of a different size than that approved by the manfucaturer, they can very easily say that a tyre that is too narrow/too wide affects how the car handles and it would have contributed to the accident.

[peterwwillis]

And then you take it to court, and you get a mechanical engineer and a racing instructor to say that a 215/45R60 is not going to cause an accident that a 205/45R60 wouldn't have caused, since tread wear, hardness, speed rating, structural design, and road conditions all are the most important factors in traction. Identical tires with a 10mm width difference will perform nearly identically, but the same size tire using different manufacturing processes will result in completely different traction. Tires of the same size rating but different manufacture can have comparatively narrower or wider (due to sidewall stiffness) or flatter or bulging (tread patterns) geometries.

But my bet is it's more a matter of following a contract than whether it actually caused an issue; either way I can see not wanting to deal with the potential hassle.

[bluGill]

BMW is known to specify weird size tires where nothing else will fit in the space allowed. I don't know about this car, but in general I would expect that you have a limited choice in tires.