Date:         Sat, 20 Sep 2003 12:55:05 EDT
Reply-To:     BenTbtstr8@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ben T <BenTbtstr8@AOL.COM>
Subject:      Re: Are Audi wheels unsafe on a Vanagon?
Comments: To: brettbaer@HOTMAIL.COM
Content-Type: text/plain; charset="US-ASCII"

In a message dated 9/19/2003 11:46:56 AM Pacific Daylight Time,
brettbaer@HOTMAIL.COM writes:
How would one find out which Audi Wheels are cast alloys and which are
forged?  Would this info be on the wheel somewhere; what should one look
for?
Not very many Audi wheels are forged. The greater majority are cast; so
chances are you are getting cast wheels.

One way to tell cast from forged is by looking at the bare alloy surface with
a magnifying glass (best with jeweler's loop used for checking out
gemstones). Anyway, forged aluminum will look tight and less porous to their more common
counterparts. The pores are airpockets left from casting. Forging the wheel
forces most of these airpockets out or makes them very small resulting in a
stronger wheel.

Forged wheels are also generally much lighter than a comparable cast wheel.
Since forged wheels are stronger, manufacturers will often use less material to
accomplish the same thing. In one example, I found a 15" X 7" forged alloy
wheel weigh 50% less than a cast wheel in the same style and size. Furthermore,
the weigh capacity of the forged wheel was 33% higher than the rating for the
cast counterpart.

Unfortunately, forged wheels are much more difficult to make. As a result few
designs are available. Some due to lack of demand (due to cost), most because
the forging process limits (aesthetic) designs. So there are more
good-looking (yeah, I know it is a relative term) cast wheels available vs. forged
wheels. Forged wheels tend to have flatter dish and spoke designs.

To make identification even more difficult, cast wheel manufacturers will
often make wheels identical in appearance to a production forged wheel. The most
common example I have seen of this is the Porsche 5-spoke alloy wheels
specified for the early 911's. There's a brand called Maxwheel which to the casual
observer looks like the Fuchs. I have a quick way of testing them. Oh yeah, most
cast wheels are painted. That makes them even more difficult to identify.

There you have my 2 cents on the matter. More detailed information available
via pmail.

BenT
Vanagon Cafe Alternative Wheels