Big_Chap

hello, as title really, does anyone have any proof or rough guide to the performance/speed benefits with upgrading to lighter forged alloys?

ie back to back 1/4 mile or any sort guide? must be a couple tenths to be gained?

thanks

Kriston

Its as simple as this. Less rotational mass = Less energy required to propel your car. Hence quicker acceleration and deceleration. a quality forged wheel can be several lbs lighter then your OE setup.

need2speed

Unsprung weight advantage of lighter wheels has virtually no effect on drag racing. The benefits are achieved in handling on road course situations. OTOH, "forged" is such a misused term, I wouldn't even assume they are lighter for a given size.

Diabolis

^ This. While there are huge advantages in terms of handling by reducing unsprung weight and in particular rotational inertia (think of a heavy spinning flywheel and how hard it is for it to change direction), the benefits are really only noticeable at a race track (circuit - not drag racing). The same goes for two-piece - or carbon ceramic - rotors.

zcct04

On-topic for the impact of lighter wheels:

Earlier this year Car & Driver had a flawed but interesting blog post about their attempt at a performance test of the CF wheels on Ford's Mustang GT350R.

They tested acceleration times on the GT350R with it's CF wheels, and then tested the same car with the aluminum wheels off the standard 350. They found the CF wheel/tire combo from the 350R to be an incredible 58 pounds lighter. In top gear, they clocked improvements of 0.9 seconds in 30-50 acceleration and 0.8 seconds in 50-70 acceleration. In 4th gear, they clocked a 1.2 second improvement in 30-130 times. VERY impressive gains!

But not all of the gain was from lighter wheels . . .
https://mbworld.org/forums/c63-amg-w...er-wheels.html

Diabolis

Didn't read the link - but was that the one where they used wider PSC2s on a lighter car and narrower, street Michelin rubber on the heavier car and decided this was somehow a valid comparison? Sorry, but the fact that it's C&D speaks volumes... about as relevant as Top Gear tests but only 1/1000th of the fun.

The CF wheels on the new 350R are freakin' awesome. I remember examining one closely at the auto show (they had one that was cut so you could see the cross-section of one of the hollow spokes) and wondering why premium European manufacturers don't offer something comparable.

Phil Chow

I find everytime I've gone lighter wheels, the car feels much nimbler and more responsive. Ergo, I will always get lighter wheels.

SupremePower

Better rubber should help in shaving off the tenths you're looking for at the track. Forged wheels will make your car feel like its much lighter on it's feet though as a whole. Every set we have put on a car, dependent up on size and tire of course, dramatically improve the cars turn in and feel.

Forged isn't the only option for lighter. There are some great companies that utilize flow form technology to shave weight while still maintaining extreme strength.

need2speed

I can't find fault with the stock Edition 507 wheels, super light and real forged. Well perhaps if they were 1/2" wider to fit bigger tires ;-)

zcct04

Yes. . . and I agree.

I wasn't aware that these were forged, or that they were lighter than the stock C63 wheels. Are these both fact?

need2speed

Here is a snip from MBUSA. The weight difference is very appreciable when I change over to winter tires mounted on standard 18" AMG rims.

zcct04

Thanks - I'd not noticed that! I'm now curious about how MUCH lighter they are.

Next time someone has their tires remounted, can you weigh the wheels and post the weight on the sticky called The C63 OEM & Aftermarket Parts Weight Thread ?