Just Me

Agreed. Used factory wheels ( "take offs") are often the best alternative.

Almost none will be forged. There are exceptions.

Be sure that they are round and true. I cannot tell you how many times sellers are "surprised" to find that their wheels do not meet spec - and vibrate. Maybe they are, maybe that's why they are selling. Either way, find out. Most specs for radial runout call for <= 30/1000"

Have them spun. Runout can be measured with a dial indicator or, frankly, seen while spinning with a straight-edge and the naked eye.

Grant

Just Me

Fair concern. I try hard never to do that. You are right that sometimes people measure what they can and extrapolate from there. That's called bad engineering, and worse science.

In science, we listen to those that have observed data that disagrees with theory. Its called testing the null hypothesis.

And in fact most drivers have observed what I pointed out, validating the theory.

Incidentally, a spinning wheel is NOT a particularly complex system. If it was, i'd be fuzzy about it.

Do you really disagree that heavier wheels slow acceleration, hurt ride? Or that smaller sidewalls lead to damage? Or do you just think its small enough that you suffer it for other benefits? I'd guess the latter.

Grant

ZCD2.7T

It's SO sad the amount of on-topic knowledge that AW and this forum in particular lost in the transition to IB. Sigh.

As the current/past owner of 3 C5s (2000, 2001 and now 2004 S-line), and having owned 7 sets of wheels between the 3 cars, I think I can speak to the OP's question.

18" wheels, properly chosen, will enhance most every aspect of your car. The ride will be firmer due to the shorter tire sidewalls, but with the C5s mushy stock suspensions, that may not be a bad thing. ;-)

My current setup is my favorite for this car: 18" x 8.5" B7 RS4 replicas from VMR wheels, shod with 18" Pirelli PZero Nero tires in size 235/40/18. The wheels are pretty light at about 23 lbs each, and they've stood up to everything our horrible Chicago area roads can dish out for 3+ years. No bending, no issues with the finish, no balancing problems - just really nice quality, especially for the money, which was ~ $150 each.

The offset puts the wheel edge right at the fender line, which improves the looks of the car, and the extra wheel width really makes a nice difference in the handling feel.



I bought the wheels through my local Discount Tire store so that I had local support, though I haven't needed it.

Velocity Motoring: http://www.velocitymotoring.com/

HTH.

joeq10

Thanks for the clarity. I'm a bit confused about the term "offset" though. You mention that the offset puts the wheel right at the fender edge (which is exactly what I'm looking for BTW). Do I need to do anything to add offset? Or is the offset simply defined by the differetial between my stock wheel size and the 18's I would be looking at?
Just to confirm, are you saying the 18" x 8.5" wheels will fit my car?

Thanks again,
Joe

ZCD2.7T

Check this link for an explanation of offset:

http://www.discounttire.com/dtcs/infoWheelOffsets.dos

Wheel spacers can add offset (so that a wheel clears a Big Brake Kit, for instance), but can also cause other issues, so getting wheels with the correct offset in the first place is the much better path.

My wheels are ET (offset) 38, and combined with the design of the wheel and the extra width, the stance of the car is hugely improved, IMO.

Though I can't <i>guarantee</i> that these wheels will fit your car, they <i>should<i>.

Just Me

That article is good - as far as it goes. It ends with a vague and ominous warning, btu no explanation.

As i noted above, an explanation si complex. But beware. Changing offset by more than a few mm has very negative implications. You likely wont notice much going from, say -40 to -35 (which pushes the wheel 5mm out) - but every mm distorts the design geometry of the suspension, especially the steering wheels.

It also adds strain and stress to the assembly.

Its really best to stay very close to OEM offset specs. if you need to make a large change for the wheel to fit, you have the wrong wheel.

Grant

joeq10

thanks