Check out these wheels!

http://www.foxnews.com/leisure/2012/...ntcmp=features

 

How much do they weigh? I'm also trying to find out how much the 991 wheels weigh. That would help understand if $15k is worth the diff. Thanks for posting.

 

Curb one, that will be 4 grand please. Probably no refinishing a CF wheel.

 

The key value here is that carbon fiber isn'y only stronger/lighter/stiffer, but also- I would say especially - because carbon fiber is so effective at damping vibration:

The net benefit to automotive enthusiasts (or chassis engineers) is that you have a 40- to 50-percent reduction in unsprung mass—which can yield lighter, shaper steering, better handling, and even better acceleration, while reducing noise, vibration, and road harshness. They allow some natural damping from the material itself, which is what helps them achieve impressive gains in the 9-20 Hz 'secondary ride' frequencies that are especially troublesome for chassis engineers to tune out.

Read more: http://www.foxnews.com/leisure/2012/...#ixzz2GUXoqBZe

The 991 has already made great strides in melding the luxury experience and track performance realms into one amazing machine. The addition of carbon fiber wheels will be another great stride in itself. Given all that, and I really hate to say this but, seems like a pretty good deal.

 

I would like to hear from a mechanical engineer in regard to how much of a difference the weight of the wheel makes. The wheel is so far away from the crank, when you reduce the torque of turning the wheel's mass, what does that mean in power to the ground?

 

Its not the distance from the crank that matters, its the radius from the axle. Wheels are a lot larger diameter than brake discs, axles and other parts that spin, so the effect is greater even though a wheel weighs a lot less than, say, a crank. Probably someone around here has the chops to work out the math and come up with a number, which will probably be in the range of swapping over to a K&N air filter. Okay maybe more. Not much. That's why I think the improved ride comfort and noise levels will be by far the most noticeable benefits and reasons to get these things.

Ever ridden a carbon fiber road bike? Light and super stiff yet handlebar vibration drops tremendously compared to steel or aluminum bikes. Every component in my high end audio system sits on a carbon fiber Shelf, because the stiffness and damping properties results in an obvious reduction in noise and improvement in dynamics. I bet these wheels will feel simply amazing on a 991.

 

Cf wheels are fabulous. Considering what I paid for a set of zipp 404 these are a bargain. Www.zipp.com
Then again I'm staying with my classic 20 inch summer and my 19 inch stock winter wheels.

 

Working backward from the numbers in the article, the company is telling Fox News that our stock wheels range from 16 to 20 pounds apiece. I personally have no idea. Just doing the arithmetic.

Gary

 

There is not a hope in heck that the stock 991 wheels are sub 20lbs. I don't know exactly, but the 997 19" wheels were in the ballpark of around 23lbs for the fronts and 26lbs for the rears, I don't expect the 991 wheels are much different.

Mark

 

And your point? You think these guys are underselling their product? You could drop them a note.

Gary

 

Less weight is one thing. Less looks is another. Looking at these I can't say they would do justice on a 991. But each to his own. Im sure there are other wheel alternatives available that would achieve both results.

 

I have BST carbon fibre wheels on my Yamaha R1, it is hands down bar none the best performance mod you can do on a bike. Forget the Ohlins suspension, high spec brembos, more HP, etc, etc!! Reduction in unsprung rotating mass is king!!

Interesting to read the effect on HP, top speed, turn in etc:

http://www.blackstonetek.com/inertia.html

BTW: also the best thing you can do for the bike/rider combo is to get light and ripped - do P90X every night!!

 

https://rennlist.com/forums/997-gt2-...on-wheels.html

https://rennlist.com/forums/997-gt2-...-benefits.html

 

I'll get them if they ever make twenty-inch to fit the 991. All they have is nineteen-inch (to fit the 997 and others that use nineteens). Nineteens won't clear my ceramic brakes, or so I've heard.

 

I think the effect of any substantial reduction in unsprung weight in each wheel will amplify all the good effects of the suspension in doing everything it does - increasing performance in readily measurable ways- tire weight, construction and materials being constant.

But I would guess that unless one is removing very large amounts of weight or improving balance, "power to the ground" and "dampening" effects, if there are any, are likely to be far less noticeable.