ncstingray

Signature SV502
Forgestar CF5

Suns_PSD

You win. Seriously.

Could you tell a performance difference going to 18s?

Overall weight loss if any?

Thanks

village idiot

Not forgelines, but I have forged 18" wheels. Steering is definitely lighter and feels a little more precise, but it could very easily be placebo. It's probably about the equivalent of dropping 100lbs out of your car given the lighter weight wheels and tires (vs runflat) and smaller diameter for the wheels. It's like losing 1/2 a passenger.

TCorzett

I'm sure there are good values out there, and people shouldn't just choose the most expensive option, look at the whole package and make a decision... I'm happy with the one I made. I agree that "cheap" is all relative... my mind goes back to the $1200 a set cast aluminum "rotary forged" wheels I was going to use on my G8... hoping to find an offset from a BMW that worked without having to roll my fenders (and that wouldn't bend/break on the track).

I'm going to say I notice a performance difference for the better. I have only driven one track day on these wheels/tires so far, and had a noticeable improvement in lap times. Turn-in felt much better and when entering corners off-line (due to passing between corners) I was shocked at how well the car would just take the extra steering input.

That said... How much is down to the 18" vs 19/20"? How much is the tire (BF Goodrich Rival S vs. MPSS)? How much is the extra width up-front (315 vs 285)? Honestly, I'm not skilled enough of a driver to say what... if any of those... makes for the difference I felt. It could be my increased confidence having driven the Corvette for another six months since the last time I was at that track (my previous 5 track days in the Corvette were in the first two months of owning it).

The next time I pull the wheels off I'll try to remember to get some weights of them vs. the stock setup.

Bill Dearborn

Lets start with what you want which is to reduce costs. The easiest way to reduce tire costs is to choose a set of wheels that provide a wide range of tire options including used race tires. Once you know where you want to be then you can choose from different manufacturers or new Vs used wheels.

The hot set up on the C6 wide body cars is 18x11 front and 18x13 rear. I have a set of CCW C10 wheels that I used on my C6Z. When I got the C7Z I just put them on it. The 18x13 rear wheel is a shade wide when installing the wheel since it will just contact the upper control arm on either the C6 wide body cars or the C7 when the car is off the ground. You can run a small spacer to reduce the problem but it isn't necessary as I have never had the wheel contact the UCA when running. If you have CCW wheels and the ceramic brakes you will need to use a front spacer as the ceramic brake rotor has a dished in area in the center. This area isn't large enough in diameter for the CCW to fit into it so the wheel doesn't fit flush against the rotor. CCW makes spacers that will fill the space so the wheel seats properly. To avoid installing longer studs I use extended thread lug nuts that extend .3 inches through the wheel and provide the required number of threads to hold the wheel on. I have heard the Forgelines have smaller diameter hub faces than the CCWs and they do fit inside the depression in the rotor like the stock wheels do. There isn't more than a few thousandths difference in diameter but that difference means the CCW wheel rides on the radiused edge of the depression instead of inside it. Thus it is impossible to keep the wheel from moving slightly. Over a period of time that results in the wheel studs breaking off. I had that happen on my C6Z at the NCM VIR event in 2015 and I lost the left front wheel going around Turn 1. A $4K mistake that I won't make again. With the spacers everything is fine.

If you want to run the Pirelli Slicks the 325/660 tires will fit on the 18x13 wheel but they are stretched way out. For a better fit I recommend choosing an 18x12 wheel which should be able to handle everything up to a 345/35/18 Hoosier although the 18x13 wheel is perfect for the Hoosier.

The CCW wheels are tough. When my wheel came off at VIR it gouged up pretty bad on the hub face and I thought it might have been bent through the hub. I sent if off to CCW and they checked it over, smoothed over some gouges in the hub face and said it was good to go.

After starting to use the Pirelli slicks I decided to drop down to an 18x12 rear wheel and after looking around for a lower cost replacement chose an OZ Racing 18x12 rear wheel that is designed for the C6Z. The offset is 2mm different than the offset the C7 requires which means it fits. I am running Pirelli 315/680 tires on it and they are stretched a little but the probably wouldn't have fit the 18x13 CCW.

Do a search for CCW and Forgeline wheels for sale in the C6 Parts for Sale and Autocrossing/Roadracing Classifieds to see what you can find. I found my CCWs in the C6 section three years ago. They were practically brand new and I got the full set with a set of scrubbed A7 Hoosiers shipped to the house for $3500.

Bill

CanadianVetster

Listen to Bill !!

fatbillybob

Does forgestar make a wheel? Those pos are cheap and hold up to racing. A lot of us use them. I was skeptical but a believer. I'm beating on mine right now at Buttonwillow and I'm a curb beater.

CW4L

Gotta use a track rated wheel like Forgeline if really tracking why put cheap cast wheels on a race car to have them fail? We have 18” all day for any c7 and ckear big brakes just text or call 440-915-6166. Not all wheels are created equal!

Don Pablo GS

C6 Z06 wheels 18/19 with nitto NT01 275/325. Two track days so far no problems

TCorzett

Had the wheels off to replace brake pads...

Stock Grand Sport wheels and tires:
Front with 295/30-19 MPSS = 52.6lbs
Rear with 335/25-20 MPSS = 60.4lbs

Forgeline GS1R Open Lug w/Cap:
Front (18x11) with 315/30-18 Rival-S = 51.6lbs
Rear (18x12.5) with 335/30-18 Rival-S = 53.2lbs

On the front increased the wheel/tire width and still lost at least 1lb each... the rear is over 7lbs each. Both sets have TMPS, so that should be the same.
The stock tires are near end of life (front is down to the cords) and the Rival-S are fairly new and have a bit of pick-up from my track day on Sunday.




zZpe57G.jpgp

96GS#007

I know this thread is two months old, but curious if you've put any more track days on your setup.

I have a 2019 Grand Sport on order. I have a set of OEM C6 Grand Sport wheels with NT01s that I use on my 2013 Grand Sport for track days. Would certainly be nice to keep using the same wheels/tires vs needing to sell the C6 GS wheels and then buy new and significantly more expensive wheels for the C7 GS.

Innovate

I am wondering why no one has mentioned BC Forged, way cheaper than Signature (actually they are the same, made in the same factory) by $1k roughly and cheaper by a little bit than CCW.

I am on a Forgestar budget though.

Don Pablo GS

Three days total now. Tires look like they could go another 3 days. This setup is fine for my skill level. I'm not seeing any understeer. At full lock in the parking lot there is a minor rubbing in the front (on the spats I think) because the offsets are slightly different on the front C6 wheels. If you were happy with that setup on your C6 I think you'll be satisfied with it on the C7. I won't hurt to try it first since you already have the wheels.

dparm

Any other photos? I've got the same car and would be curious to see them, as it's a wheel I'm considering.

TCorzett

I have others from the track, but the wheels are in motion... so not much to see.

dparm

That looks outstanding. Thank you!

Do you have issues with brake dust spraying onto the spokes and permanently embedding in the finish? All four of my OEM wheels are basically ruined from that. There's a bright silver band on the spokes that lines up perfectly with the calipers, so now I'm hesitant to order another set of black wheels.

village idiot

We were at the same event. I think Bernard was your instructor, right?

ECR is really gentle on tires. Brakes and engine, not so much. I can probably get 4 days out of my Cup2 tires there running 1:57-158 all day long, which is pretty fast there.

I run 315's in the front on my 18's without any problems.

TCorzett

I've not had any issues like those you're describing and I've not been the best regarding washing the wheels after track use. That said, the wheels don't get wet before I wash them (lack of rain out here in CA), which might help keep the dust from etching into the wheel... I'm also still using the OEM pad material. On my Pontiac I do get the brake dust etching into the painted/clear coated wheels, but since they're sliver I can't tell from a superficial look after the caked-on brake dust is washed away (using a good "turns purple" wheel cleaner really helps get rid of the stubborn dust).

dparm

Thanks. The guys at the shop who did my Xpel + Cquartz weren't 100% certain what was happening, but they agreed with my speculation that the ultra-hot brake dust is basically getting baked into the paint finish. I am using DTC-60 pads and the thermographic paint on the rotors is indicating ~1100 F peak temps!

BTW do you run the Rivals on the street? They look like they should be fine for street use, even in the rain. My Cup 2s were worthless if it was wet out.

TCorzett

The Rivals are fine on the street, but they aren't my primary street tire (I use the OE wheels/PSS for that). In early April I realized that my PSS were showing chords on the inside edge, so did all my driving on the Rivals up until last week... nearly 3400 miles (and 3 track days). I'm sure I've driven them on wet roads, but I'm not sure how wet it was (we don't get much heavy rain that time of year here in CA). There's a good amount of tread, so I wouldn't see it being an issue... I always use rain mode when the ground is wet, having seen what a difference it makes on a skid pad.

The only downside I can find with the Rivals on the street is that they're not run flats... not having that peace of mind (or a spare tire) for daily driving could be a bit of a concern.