Wheel offset question

[H]

On Thu, 2 Nov 2006 12:32:36 -0700, Chris Thorp wrote:

>Should I expect any  
>major issues going from a factory ET45 wheel to an aftermarket ET30  
>wheel on a '00 A6 2.7t?

I'd think that's enough of a difference to affect directional
stability noticeably. Check for bump steering and the tendency to pull
out of ruts in the road. It is a true PITA to drive a car that does
not want to go straight.

>I've got about a 1/4" or so between the spokes and the calipers.

The clearance between calipers and spokes is not directly related to
the offset. Offset describes where the tyre is located relative to the
hub (and caliper). When you check for fit, remember that the caliper
may move outward when the pads get replaced (I don't know how your
particular calipers are designed, so this might not be an issue).

You will be looking for clearance between tyre and sheet metal (you
are moving the tyre outwards). Imagine a tight corner at high speed.
The outer suspension will be compressed and the wheel angled, so the
tyre may rub. Not only will the tyre be ruined, but also your paint.
Maybe that's how the current tyres got the way they are?