Gearhead Jim

I've been told that the chrome Gumbys are forged, and then also told the polished Gumbys are forged too.

Talon says the new 2011 Coupe/Vert wheels, painted or chrome, are cast.

What about the 2005-2007 base wheels, and the 2008-2010 split-spoke?

I'd guess that forged is usually better, but modern casting techniques can produce some very strong parts in steel. One pistol maker switched from forged frames to cast, when they went to a more powerful cartridge and needed stronger frames without changing the dimensions.

Thanks!

Blue Demon Owner

My 2008 polished Gumbys are definitely forged, that's why I ordered them.

I can't speak to any of the other wheels.

AORoads

split spokes are cast wheels. and yes, polished or chrome gumbys are forged. to my knowledge, all '05-'07 5-spoke wheels are cast.

someone can comment on cast/forged wheels in Z06, and newer GS models. but if IIRC, none of the 5-spoke GS wheels are forged.

you've probably seen the posts of the '05/'07 wheels in major accidents, but holding up until the last stop/cracking. I think they're really well made.

07MontyRed

Gumby's (in any finish, they are all the same underlying wheel) are the only forged factory wheel for the base C6 coupe/vert.

Can't speak to the wider (X06/GS/ZR1) wheels ...

Gearhead Jim

If forged wheels are indeed stronger, that should mean the Gumbys are either stronger than the cast wheels, or lighter with the same strength.

Anyone know?

68sixspeed

c6 z06 (split spoke) wheels are spun cast, early ones were made in the usa then they switched to speedline in italy due to delivery problems. I'm not sure on the newer spider style but I haven't heard of any changes.

07MontyRed

When I weighed my polished Gumbys versus my original cast 5-spokes, the fronts were 1 pound lighter and the rears 2 pounds lighter. The scale only had resolution to a pound (its a digital bathroom scale) so it could be a little either way ...

AORoads

usually, they are both: lighter and stronger than cast. but for the street (and even some forms of racing), cast aren't bad.

gbgary

i installed chrome gumbys this weekend. handled these and my '07 chromies a lot lately and the gumbys are noticeably lighter.

Walt White Coupe

05 Cast Wheels after crash.
.

AORoads

that's one of about 3+ that I've seen attesting, imo, to the strength of standard, cast wheels made to GM specifications.

Gearhead Jim

Yeah, we complain about some of the shortcuts GM takes to save money or weight on the Corvette. But all of the C6 factory wheels seem to hold up very well.

HarleyB

IF forged wheels are so superior, WHY are they NOT on any ZR-1 or Z06? If 400, 430, and 436 HP cars deserve the strength of forged wheels, why don't 505 and 638 HP cars get them as STANDARD? I'm just saying.

cartop2

These chrome wheels on 2009 are forged and cost $1825 extra. I hope to never need them, but they were on the car I picked, so I have them.

http://forums.corvetteforum.com/c6-c...-thrilled.html

Forged material is going to be stronger than cast material assuming the forging is set up correctly and the machining takes advantage of the grain direction in the forging.

Castings can be very strong, but with the assumptions related to good design and farbication processes, I would bet on the forgings being stronger.

DaveC6ZHZ

The seven spoke "wagon wheels" that were factory options, like on the 08 ZHZs, are forged aluminum.

AORoads

Those are what we call "gumbys" because of the design. And both chrome (yours) and polished versions of those original equipment (but optional to buy) are forged wheels.

Gearhead Jim

Good question. Some possible answers:
1. The Gumby spoke shape wouldn't work well with casting.
2. The forged Gumbys were supposed to be the first in a transition to all-forged wheels, but the GM bankruptcy derailed that idea.
3. GM was worried that the chrome would not work well on cast wheels.
4. Somebody goofed when they wrote the specs, the Gumbys were supposed to be cast.

Talon 90 (Paul) probably knows, but he might not be able to speak freely.

george vee

Here is a pic of chromed forged gumby,

Walt White Coupe

Ugly caliper.

george vee

Stock caliper. What do you have?