YA911Fan

Think inertia -- both translational and rotational. More mass means more inertia. The lower the inertia, the easier it is for the suspension to maintain tire contact with the road surface, especially a bumpy one. The rotational inertia is more of an issue in small, low powered cars.

KeninBlaine

I understand and agree (being a mechanical/maniacal engineer) about the inertia thing. However, I still don't know how the theory of it translates into the experience of it. In a blind test, could the average driver distinguish between a set of Champions and a set of Sport Designs?

KeninBlaine

B911S: You hit it right on the head. Well stated. I agree 100% with finding other ways to knock off some car weight rather than spending $5000 to save perhaps 20 pounds (if that is the main objective of spending the $5000).

kauai_diver

One of the two main reasons Porsche has Ceramic disk brakes as an option. Lower rotational inertia and stable friction from high speeds and temperatures.

Forget the order of magnitude but isn't 5 pounds unsprung weight equivalent to 20 pounds of sprung weight?

jhbrennan

Yes - I'm an "average" driver and I switched from 19 inch OEM to 19 inch Champions and felt a noticable difference in handling and response on a C4S. I then changed to 20 inch (bigger wheel + bigger tires = more weight) and could feel that difference too. I'm sure you could tell the difference in a blind test.

CBnAT

Exactly, kick a bowling ball or kick a soccer ball? Try to stop a bowling ball or try to stop a soccer ball?

That being said I don't know how much weight change it will take to actually pass a seat of the pants test.

mdrums

OK... there is a mountain being built out of a mole hill here....

1-if you take your car to the track and are a pro driver you will be able to tell the difference in some of the wheels weights.

2-If you are just going to the track for DE then you will not be able to tell..maybe can tell with many years of track time.

3-If you are just driving around on the street you will not be able to tell any difference so just get what looks the best to you.

mglobe

It seems to me that the weight differences between the Porsche wheels is really nominal, and that if you are one who feels that wheel weight is truly important you should be looking after-maket rather than the relatively heavy Porsche wheels.

b911s

Bingo!

Edgy01

I have to say that I can feel the difference in having the PCCBs. Tires are extremely heavy in these sizes so the contribution of the wheel to all of this seems so minor. Here are the sizes again for this thread,--been saving them for awhile...

Porsche 997 Wheels

Porsche Factory Carrera S - 100 lbs, 0 oz.

8x19" 22 lbs. 4 oz.
11x19" 27 lbs. 12 oz.


Porsche Factory Carrera Classic - 104 lbs, 10 oz.

8x19" 23 lbs. 10 oz.
11x19" 28 lbs. 11 oz.

Porsche Factory Carrera Sport Design - 104 lbs, 12 oz.

8x19" 24 lbs. 3 oz.
11x19" 28 lbs. 3 oz.


Porsche Factory Carrera Sport - 106 lbs, 12 oz.

8.5x19" 24 lbs. 2 oz.
11.5x19" 29 lbs. 4 oz.

8x19 (987, 997 non turbo front) 23.4 pounds
8.5x19 (997 turbo front) 23.9 pounds
9.5x19 (987 rear) 25 pounds
11x19 (997 turbo rear) 28.8 pounds

Stock Turbo Wheels
8.5x19" 23 lbs. 8 oz
11x19" 27 lbs. 14 oz.

Factory 997 GT3
8.5x19" 24 lbs. 5 oz.
12x19" 30 lbs. 13 oz.

Tire Weights:

Potenza RE050A 24/32
ContiSporrtContact 2 21/29
Pilot Sport PS2 22/28
P Zero Rosso 22/28
Advan Sport 24/30