FruiTay

I've always wanted some CCWs but I gather that the stock wheel sizes for my C5z are the best for all around performance. I take this car on long cruises and to open track. Would getting 18's sacrifice performance?
Thanks guys!

FruiTay

Guess I can read the stickies....

MarkDFW

Forged 1 piece wheels are best for road racing. 18s all the way around will give you the best tire choices, by far. If 18s sacrifice performance then race cars wouldn't run 18s all the way around.

I bit the bullet and got CCWs last year (18x11 front and 18x12 rear) and am buying scrub race tires. Best decision I have ever made. My lap times have plunged. Going from street tires to R Comps on a local 1.7 mile track is saving me 5 seconds a lap. That is huge.

GT Racing Tires

What he said!

FruiTay

What are the advantages with one-piece wheels? I have read the advantage with 3-piece is that you can take them apart for repair and it is much cheaper than with a one-piece (http://forums.corvetteforum.com/auto...e-learned.html (REPLY #4))

Is it that because they are more solid being one-piece?

Thanks for the sweet reply Mark!

MarkDFW

and GT Racing Tires can hook you up on scrubs. There is no better mod for your car than R Comps or slicks. Trust me. You will never, ever, ever, ever want a street tire again on the track. Ever.

MarkDFW

Plenty of guys get the 3 piece wheels. They are a little less expensive. IMHO more pieces = more moving parts = more points of failure. That is not to say they will fail. Most every race car I can think of runs 1 piece forged and those guys are smarter than me. I'd rather copy genius than try to invent it.

CCW is regarded as probably the best bang for the buck. Very happy with mine.

blackdak318

I would look into a set of 17" CCW classics. They seem to go for a lot cheaper than the 18's and are much easier to come by than a set of 18's. Tires are cheaper and everything should be lighter with a 17 as well.

As an example I ran across a set of black 17's with kumho slicks on them for $850.

MarkDFW

Respectfully disagree. They are cheaper for a reason: not in demand and not as many 17 inch scrub race tires to choose from. Major racing series are overwhelmingly going to 18 inch wheels.

Ask GT Racing Tires what size tires to buy. They (and other companies that sell scrubs) will tell you 18 all the way around. 18 inches = more tire choices. You can pay less and get fewer choices if you want.

My 2 cents

X25

In my opinion, if you're not competing, street tires are also a very good alternative. They last much longer, and unlike slicks or most r-compound tires, they gradually squeak at the limits unlike slicks, giving you plenty of feedback before they finally give up. After all, half the fun is learning to control the car at the limits

crimlwC6

Buy two c5z rears and you'll have a full set assuming you have two currently. Then buy a set of 4 17 or 18s and you'll have 2 sets. I'm a big fan of of running nt01s on my 17s. Better than scrubs.

StreetSpeed

Going 18 all around wont screw up the TC and AH? You run 35 series rubber all around? I just bought a c5z and intend to use the stock rims this year, but perhaps will trailer it next year and switch to 18" slicks all around and keep the stock rims for a rain setup. Any issues there?

MarkDFW

The overall tire diameters need to stay close to OEM. My grand sport is about 25.6 inches front and 26.7 rear. If I divide those, take the result and I am told you need to stay within 97% of that ratio.

StreetSpeed

So do you run 40 in the front and 35 in the rear? Don't see how your diameters change if you're not using different size profiles? Sorry for the newb questions, but we're close to answering a question I've had for months now!

JeremyGSU

I have an '04 Z that I've done 15 track days with. I have over 60 under my belt.

For the first 11 I ran on the stock wheels with 275/40/17's & 305/35/18's with Nitto NT555R2's. I thought the car did well.

For this year I purchased 4 of the oe 18" speedlines from House of Wheels. I am now running 285/35/18 & 305/35/18. The difference was quite large. The turn in is so much quicker and the understeer is far less than it was before. I was suprised. I would not go back to the 17's. Plus, the 18's look cooler. haha.

I still run the 17's on the street.

The 555's give great feedback on what they are doing as well and really stick actually. I've driven on the Continental slicks and they weren't that much grippier IMO. Noticeable, yes. But I thought it was going to be night and day over what I use now and I didn't find that to the case.

Hope this helps.

StreetSpeed

Excellent! Any reason you didn't go 295/315? It appears on tire rack the the 315s are more readily available and cheaper than the 305s.

MarkDFW

I am on a 2012 grand sport. On the track I run kuhmo 305/30/18 front and rear 345/35/18. That is 25.5 front and 26.8 rear which is close enough to the OEM ratio that I am fine. Go to tire rack. When you go to the specs of a tire it will show overall diameter. I can't speak to if you need 40 or 35 without knowing your OEM diameter and the diamaters of the exact tires you are looking at. Just keep the front/rear overall diameter ratio to within 3% of the OEM ratio. I've been told by several people that you won't have any issues. The car is looking at speed of front and rear tires. If there is too big a difference from OEM, nannies kick in as it thinks you are having traction issues.

96CollectorSport

If you have a C5Z you can run a square set-up with no problems at all - almost all C5 T1 cars / PTA / ST2 cars run square set-ups with no problems. The C6's get fussy when you get too far away from stock diameters not C5's. You can run up to a 295 up front on a C5 (depending on sidewall height) without rubbing - bigger than that and you better have stiffer springs on so the tires don't hit the fenders. We run 315/335 on our ST2 cars and 315's square on our T1 car without issues.

The lightest wheels are going to be forged 1 piece wheels, however the advantage of a 3 piece wheel is that you can replace pieces instead of the whole wheel. So if you are doing W2W a 3 piece is nice if you do a little rubbing. The outer wheel lip is usually around $200, better than a new $500 - $600 wheel.

If you are just starting out doing HPDE's stick with street tires your first season or so, until you are very comfortable on street tires - with race tires/slicks you have to worry about tires being up to temp/heat cycles etc. So if you are still learning the car you will get more feedback from streets - which helps you learn.

johns68

I ran square (because I already had 'em) on my C5 with no problems ... 315/35/17. 17" CCW classics, btw, which are 3 piece and again, no problems.

Then I flared the fenders, and currently run 315/18 and 345/18 on CCW one piece forged. Again, no problems at all.

When I bought the 18's, John sent them with a barely used scrub set of slicks installed. Grip was awesome ... after a couple laps. I'm running A6's now. Grip is there from start, and with the large tires and relative light weight of my car, they don't fade before the end of a 20 minute session ... but if your getting started leave the streets on for a while. They talk to you. Race tires don't. They grip until you push too far, then they don't. No warning.

hellrazr

It would increase your unsprung and rotational mass.


I went down the route of having two sets of stock wheels and running sticky-*** scrubs (r compounds). I decided to go back to street tires. Here were my reasons:

1. I didn't want to drive to/from the track on track tires or transport them separately.

2. With the increase traction afforded by R-compound or slick scrubs, other parts on the car started to wear out and fail faster. These parts have to be upgraded.

3. Expense. Staying stock is cheapest if the goal is to get laps rather than lap times.

With street tires and stock wheels, I love having the ability to simply drive to the track, get on it, take the car to it's limits while also managing stock limitations, and driving home. A Z06 is a great fun car as-is stock, and it lasts. Although the stickier scrubs are a blast, it's much funner to not have to work on the car by changing wheels, upgrading parts, dealing with broken parts, etc.

I see many folks upgrade from street tires before they have realized the full traction potential of street tires. I got into a car with a guy that felt he reached the limits of street tires and wanted to upgrade. Although the car was sliding beyond the limits of the tires, the tires would have actually had more grip if the car was driven more smoothly. I've experienced the same with guys using rcomps and slicks.

So, if the goal is to simply go faster without investing time to improving driving skill then yeah, get some sticky scrubs and have a blast. Otherwise, stay stock, have someone with high-level competitive racing experience and success show you what the car is capable of on street tires, and stay with street tires until you can be in the same ballpark.

Either way is fun as hell