Not that I want to fan the 15" wheel flames here but there are a few things
to consider when it comes to wheel loading and if a Audi / Passat wheel can
take the weight of a Vanagon or not.  So, not that I am pro or against the
Audi / Passat wheel, but here are some bonifide questions to ask about 15"
5x112mm wheels in general.

- Are the 15" Audi / Passat wheels the same part number as the Audi A6
wagon or the A8?  If so, what is the GVWR of these cars?  Is it the same as
a Vanagon?

- Most things are over engineered - it is the ultimate CYA.  When I was at
school to learn electronics we were always told to get a resistor or a
capacitor that can handle at least 20% more than you will ever throw at it.
 I would suspect the same is true for wheels if not more so... as it has
been pointed out on previous posts "would you trust your life with it?" -
you may, but Volkswagen sure isn't - read "law suit"!  This is why I think
the wheels are over engineered so there is NO chance of them deforming on
the car they were intended for (let go air born, hit a curb, massive pot
hole etc).  You may be getting closer to the "real" tolorances with the
Vanagon - is it a safe thing to do - perhaps, perhaps not.

Now on to my *guess* (usual friendly disclaimers apply here) to weather a
Audi wheel would be safe for a Vanagon:

Weights of my vechicles (measured at local truck scales)
1988 Syncro Double Cab GVWR = 2500kg
1987 Audi 5000S Quattro GVWR = 1960kg

Each wheel at rest on the Vanagon would support 625kg
Each wheel at rest on the Audi would support 490kg

625 / 490 = 1.275

So, if you had my Audi 5000 Quattro wheels on a fully loaded Vanagon you
would be over by 27.5% - Is this good?  Well you be the judge of that one.
It is also interesting to not the maximum axle weights:

Vanagon         1300kg = 650 each wheel
Audi            1040kg = 525 each wheel

650 / 525 = 1.238 or 23.8% greater load if installed on a Vanagon.

Personally, I would tend to think twice about putting the wheels from my
Audi on to my Vanagon unless I found out that they are the same wheels for
a heavier A6 or A8.  According to one web site the Audi A6 Avant (wagon)
has a curb weight (empty) of 1650kg, my Double Cab weights 1800kg.   If
they are the same wheels on all Audis then I would have to say that they
could be compatible with each other seeing that the curb weights are within
150kg of each other.

Just my $0.02 Canadian worth!

--   David Marshall -                    - Quesnel, BC, Canada   --
--    78 VW Rabbit, 80 VW Caddy, 84 VW Westie, 85 VW Cabriolet   --
--       87 Audi 5000 Quattro, 88 2.0L VW Syncro Double Cab      --
-- David's Volkswagen Home Page        http://www.volkswagen.org --
-- Fast Forward Autobahn Sport Tuning  http://www.fastforward.ca --
-- david@volkswagen.org (pmail) or vanagon@volkswagen.org (list) --