"Mike Mayer" > wrote in message
...
> The new '06 330xi comes with 225/45R 17" run flats. I don't want them.
>
> That tire by the way, is a 25" outside diameter tire.
>
> I would rather go with something more conventional for the rough NE Ohio
> winters - wider sidewall aspect to absorb the rougher roads is a good
> start, and even the Bimmer website mentions this warning:
>
> "Due to low-profile tires, please note: wheels, tires and suspension parts
> are more susceptible to road hazard and consequential damage. Performance
> tires are not recommended for driving in snow and ice."
>
> So, where does that leave us who live in wintry climates half the year?
>

It leaves you owning two sets of tires, one for summer and one for winter.




> Thinking along the lines of (don't laugh - I have my reasons :-) ), the
> Goodyear Asssurance Triple Tread, which the closest size fitment is the
> 225/50, but on a 16" rim (they don't make the 225/45 17" in that
> particular tire). A 225/50R 16 tire has a 24.9" outside diameter
> (identical outside diameter as you get with the 205/55R 16 on the 325xi).
> So, the difference in tire dia to the 25" dia with the 225/45R 17" on the
> 330xi is of no appreciable consequence.
>
> However....
>
> Question #1 is whether or not a 16" rim will even fit a 330xi (you get 16"
> on the 325xi). The difference is in brake rotor diameter between the
> 325ix (11.8"), and the 330xi (13.0" front /13.2" rear), so I don't know
> if I can even put a 16" on that 330xi.


Given the numbers you just used, 16" rims will not fit.


>
> But still, if the 330xi WILL take a 16" rim, that puts me closer to where
> I want to be, and leads to my next...
>
> ...Question #2: What to do about the spare for four conventional tires?
> Went to BMW and looked at that plastic tub bolted into the bottom of the
> trunk on the 330xi. Obviously that won't hold a tire (not even a space
> saver), so I am curious if one were to REMOVE that tub, if I'd be looking
> at the original tire well. It appears from looking at it, that this tub
> occupies a nominally large space underneath, but whether enough to fit a
> spare, I don't know. I didn't think to look from underneath the car -
> that would have revealed more.
>

Since the bodies of the two cars come off of the same stamping machines, I'd
guess that the tire well in the trunk is the same on both cars.