993RS

The French testers did mention that turn-in was much more precise with the 18" wheels and that it was clearly superior on the track. The only point they were making was the slower acceleration.

993RS

Sorry, I was unclear in formulating the wheel weights. The figures refer to wheel pairs, i.e. both front front wheels weighing 17 kilos, etc. That the BBS front and rear wheel pairs both weighed in identically was explicitly stated in the article.

Jim

I think those small wheels on CanAm and Formula One cars were on the front of the cars, and were there to reduce frontal area and subsequently the drag coefficient. Prior to the engineering of modern ground effects, they tried everything...remember the six-wheel Tyrell, or the Chapparal with the huge fans sucking the car down to the track? If we want to reduce the frontal area or our Porsches, we'd have to put 155s on our 11 inch wheels, too.

No thanks, I'll stick with my big fat 18s on my C4S, sorry for the pun.

Carlos

Two words, gear ratio.

Todd

Hmm. Mybe I should put 18" on the 73...
Would I even be able to turn a corner w/ 18" wheels and no power steering???

A.J. - 95 993

I'll wander a bit off topic here - why is it that the current F1 wheels are so small in diameter (13"?) and have such huge aspect ratios? Is it because of regulations, or weight savings? I don't understand why they don't use larger diameter wheels and low profile tires given the same circumference. Seems like the sidewalls would roll over being as tall as they are. Though, in the super-slo-mo's I've never seen a sidewall so much as flex. Those tires sure are optimized!

Greg Fishman

[quote]Originally posted by A.J. - 95 993:
<strong>I'll wander a bit off topic here - why is it that the current F1 wheels are so small in diameter (13"?) and have such huge aspect ratios? Is it because of regulations, or weight savings? I don't understand why they don't use larger diameter wheels and low profile tires given the same circumference. Seems like the sidewalls would roll over being as tall as they are. Though, in the super-slo-mo's I've never seen a sidewall so much as flex. Those tires sure are optimized!</strong><hr></blockquote>


AJ,
I think it was to limit the size of the brakes and to slow the cars down.
Greg

Ray Calvo

I think Carlos is right - "gear ratio". In other words, is the rolling diameter the same for both sets of tires/wheel combos? If not, your acceleration is noticeably affected.

Rotational inertia could affect things, but I have a feeling difference is down in the mud on a street car with any street wheel/tire combo - about similar to what you get in differences beween successive tests on the same car.

You trust the French to tell you the truth about a German car?

Buy what you want - but keep in mind differences between clobbering a pothole with a 17" vs. 18" Porsche-compatible wheel.