Wheel offset question

[Taka Mizutani]

Let me just make sure I understand you- you have 0.25" clearance for your
brakes having test fitted the wheels you are buying?

If that is correct, then you are FINE. :-)

The 15mm offset difference will not be too much to worry about. It will
affect
your scrub radius (I don't understand this, but I'm sure someone can
explain).
Other than that, no big deal.

Two things to check, though- much heavier wheels will affect your ride
quality
significantly; and your alignment is the most important factor in proper
tire wear.

ET30 would be pretty common for front wheels for big MBZs- S-Class and the
like.
ET32 is the OEM offset for a bunch of MBZ wheels, I'd make sure that you
don't
have a staggered set (rear ET13 won't fit w/o modification and staggered
wheels
are really not right for an Audi in terms of handling and the look).

Taka


On 11/2/06, Chris Thorp <thorp at spacia.org> wrote:
>
> I was buying used wheels.  I did a test fit before buying and that's
> where I got the 1/4" number from.  I did realize that offset and
> spoke design are two different contributing factors to brake
> clearance.  The stock ET45's clear by about 1/2", but only because
> the spokes are really cupped in exactly the right way to clear the
> brakes.  (Go figure for stock wheels...)  The new ones are a bit
> flatter but also less offset, which cancel each other out.  The
> wheels were supposedly from an Audi, then run on a Passat.  They look
> like (and probably are) the Borbet CF wheels, as shown on the Borbet
> website.  What normally runs an ET30?  Maybe an MB?  (They're in 5x112)
>
> Since they were $100 for the set, in reasonable shape, I figured I
> couldn't go too wrong.  I was just wondering how much an effect 15mm
> less offset would have on handling as well as suspension and tire wear.
>
> -Chris
>
> On Nov 2, 2006, at 3:39 PM, Taka Mizutani wrote:
>
> > Chris-
> > I know this isn't well documented, but I cannot stress enough that
> > you cannot
> > determine wheel clearances by the offset.
> >
> > This is a mistake that is done over and over again on cars with big
> > brakes- I see it
> > all the time on NASIOC, quite a bit elsewhere as well.
> >
> > Wheel clearances are determined much more by the spoke clearance,
> > which is totally
> > dependent on the wheel design.
> >
> > I ran ET45 S4tt Avus on my car with bulky 996 calipers w/o any
> > clearance issues. I've
> > also run ET35 Oettinger wheels and ET30 AZEV wheels w/o any
> > clearance issues.
> >
> > If you're not sure if it will fit, you MUST test-fit before buying
> > or find someone who has
> > the wheels you're interested in and can verify fitment.
> >
> > If you're running the stock brakes, checking to see if a major
> > vendor (like Tire Rack) sells
> > the wheels you're interested in and sells them in a fitment for the
> > A6 2.7T would be a good
> > move.
> >
> > What wheels are you considering? ET30 is a bit unusual for an Audi
> > wheel.
> >
> > Taka
> >
> >
> > On 11/2/06, Chris Thorp <thorp at spacia.org> wrote: Yah, I know,
> > wheel offset has been beaten to death.  I searched the
> > archives and couldn't find anything conclusive.  Should I expect any
> > major issues going from a factory ET45 wheel to an aftermarket ET30
> > wheel on a '00 A6 2.7t?  Also, how little clearance is too little?
> > I've got about a 1/4" or so between the spokes and the calipers.
> >
> > -Chris
>
>