The stock wheels (style 159) that come with the '06 330xi are 17"x8", 34mm
offset.  That's for the tire size the car comes with, 225/45 17.  Car won't
be delivered for another month or so, thus I don't really have a car to try
wheels on for size.

Got a good price on Borbet TS rims from TireRack for same vehicle, which
I'll use for snow tires, same size as summer tires (225/45 17).  The rims
they sold me are 17"x8.5", 40mm offset, so the sizing is different - but
they say they were fitted specifically for the car.  Live in NE Ohio that's
the reason for the snow's eventually.

TireRack says check for fit before mounting tires. So I took 1 of my
Borbet's to BMW and they kindly put a new 330xi up on the rack.

Keeping in mind the suspension is fully lowered, the stock BMW wheel had
about 3/4" clearance between the edge of the stock wheel rim and the
shock/strut.

When he mounted the wheel to the hub (no tire, just the wheel), the
clearance was only 1/4", maybe less.

To me, that's too close for comfort.  I called TireRack with the intention
of returning the 8.5 width Borbet's to exchange for one's not so wide.  The
person at TireRack said it will fit fine, as long as there's clearance, and
to not worry about it (plus they have a fit guarantee, even after tires are
mounted and on the car - return at their expense).

I got to thinking later that he was probably correct - since at BMW I did
not have a tire on the wheel thus we couldn't see how the clearance would
change once the suspension is back to a normal resting position with full
weight of car on it (couldn't lower it, no tire).

I'm thinking that as the strut compresses, and the geometry of the control
arms/hub/strut changes as the car settles onto the ground, that the gap will
actually grow and not be a problem.  The "wheel size calculator" on E90.com
showed I'd be LOSING 12mm of clearance at the strut, but that the outer edge
of the wheel would be same.  That's going from 17"x8", 34mm offset to
17"x8.5", 40mm offset.

It's just that the gap seemed to close.

Anyone else know if that clearance widens as the car goes back on the
ground?

Thanks, Mike