NetManiac

I'm going to be picking up a spare set of wheels for track use in the next month or so. There are a lot of people in our PCA that use Kinesis. Barring any major arguments to the contrary I'm probably going with the K5's. However, I would like the learn a little more about them (and wheels in general) before making a final decision. I notice they have Forged vs. Cast. What the major difference?

I'm also curious about the sizes. I know the wider the better so I plan to maximize the width for my car, class, and tire. But I'm unsure about the diameter. I have the stock 17" on now, and was planning to stick with 17's so I can swap tires back and forth (at least until I start using slicks). But there seems to be a lot of chatter about 18's. Are they THAT much better? How so? If its just the footprint and it's only a few millimeters than I think I'd rather have the ability to swap tires.

Also, if I get these wheels for my Boxster now, will I be able to use them on something like a 964 later?

Thoughts? Opinions?

Bill Gregory

Mike,

Read the Kinesis web site, where they describe cast vs forging the centers of the wheels. Although there have been major advancements in the strength of cast centers, I believe forged are still stronger.

With 18's, the sidewall is shorter and thus stiffer. Your Boxster can easily support 18's as long as the offsets are correct. The Boxster offsets are very similar to 964's (around 52mm-55mm). Note Porsche has never approved 18" wheels for non-Turbo 964's, although some 964 owners do drive and track with 18" rims.

As your wheels/tires get wider, offsets get more important. For example, on 964's, the factory offsets, front and rear, are 52mm. Larger wheels in the back, like 9.5" or 10" require smaller offsets, ranging down towards 47mm, to run without spacers.

NetManiac

Cool, thanks Bill. Now all that talk about offsets makes sense.

So 18's with a stiffer sidewall means less understeer? Woohooo!! I'm sold. 18's it is.

I have been to Kinesis' web site a number of times but never notice the description of Cast vs. Forge until you mentioned it. Again, thanks.

Danno

"So 18's with a stiffer sidewall means less understeer? Woohooo!! I'm sold. 18's it is. "

No because both your front and rear wheels will pick up traction, so the F/R balance will remain the same. The shorter sidewalls give less lateral flex so you'll have more responsive and quicker turn-in. But maximum grip shouldn't be that much greater than any other tire of comparable tread width. Tire compound makes a bigger difference in cornering-grip than wheels, or suspension mods.

Bill Verburg

I use K5s and love them. The Supercup is the only cast center Kinesis that I know of.

Cast will be weaker than forged. That said I have seen plenty of cracked forged Fuchs & Fikse wheels as well as cracked Supercups, never a cracked Kinesis forged ctr(I am sure that it is only a matter of time though)

The current advantage is w/ 18s as there is a greater selection of lower profile tires. That appears to be changing as I am starting to see 35 series 17s as well. Lets hope the tire manufacturers continue to expand their lines in this area.

For track use I would prefer an 18, but for dual purpose I would rather have 17s only because potholes are that much worse w/ 18s.