Nov 5, 2017
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Mississauga
VetteCoins
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1999 C5 Coupe, 6 spd
Need advice about changing my 17"/18" C5 Wagon Wheels to 18"/19". I plan to go with new tires too of course (245 front / 285 rear).
Looking at aftermarket (Cray or similar) or used C6 wheels. What offset should I be using - what other specs should I be aware of?
If not Cray - what other wheel mfg's make strong, light wheels for Vettes?
 
Ron, a couple of years ago I felt it was time to replace the Goodyear F1's on my car. They were not worn but were getting old. I discovered that in the 17/18" range there were not a lot of options available for tires. I decided to buy new wheels and tires at that point and thought 19" all around would work. Lots of tires available which turned out not to be quite the case once the order was placed.

I contacted CCW in Florida which I believe is now Weld Wheels to enquire about their model SP 16A wheels. I wanted something that in the future would accept a big brake conversion, I wanted a lip on them but I did not want them to stick out past the body work and I wanted some assurance that the selected tire size would not negatively impact the active handing, maintaining the required tire diameter difference front to back. So this is what I got.

Fronts

19" x 9.5" with backspacing of 7.30" and an offset of + 52
1" lip
Tires Michelin Pilot Super Sport 275/30/19 (*)

Rear

19"x 11" with backspacing of 8.15" and an offset of + 64
2" lip
Tires Michelin Pilot Super Sport 305/30/19

The above may not be applicable to all manufactures wheel sizes but should give you some idea. Have a look around to see what is available in your preferred tire brand, make sure what you want is available. There are so many good looking wheels on the market, light, strong as an added benefit. Some ugly ones as well but to each their own!:Biggrin:

At the time CCW had really cheap shipping rates in the US, Canada was a killer. I shipped them to my buddy in Michigan and went down to pick them up. I did declare them at the border and paid the duty, they were kind. You might want to consider, I think the company is CBI in Buffalo and other border towns, where you can have things dropped shipped. They will let you know when the order arrives and you pick them up. Just a thought.

Good luck with your decision and show us some pictures when you get them installed.

(*) When it came time to ship the wheels/tires there were no 275/30/19 anywhere so I ended up with 265/30/19 which work fine.
 
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Thanks for the info on wheels/tires. I was told by an automotive engineer that it was important to keep the fronts one size lower than the back because that's how the computer system is programmed to handle the ABS and Active Handling System - it expects to see the front wheels turning more often than the rear. I've also heard from guys that have done like yourself - same diameter all around. I imagine either way it's difficult to prove unless you put the car on a track and pushed everything to the limit.
I bought this car (1999) a couple months ago from a friend who only put 27k kms on it in 18 years. It's like brand new of course but the original GoodYears are like hockey pucks to drive on and even though lots of tread, likely not safe anymore either. Good enough to store over winter though. I'm not sure if I want high performance tires next time around. Summer only for sure but also something a lot quieter and smoother ride. Probably not run flats this time either. I'm a Michelin fan for certain so hope they have an option that works.
You're right - there are lots of wheels to look at - just want to make the right choice regarding offset and clearance for larger brakes down the road, etc.
 
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Hi Ron!

I’m shocked I haven’t seen this thread yet.

You are correct about the different diameters between the front and rear tires. The computer likes anywhere from 0.5” to 1.5” smaller diameter tires on the front of the car when compared to the rear. As I’m sure you are aware, this can be done while using wheels that are the same diameter by using tires with a smaller diameter on the front either by a going with a tire with a lower aspect ratio or a tire with less width but the same aspect ratio such as what Murray has done. His rear tires are 26.2” in diameter and because he uses 275’s on the front instead of 305’s, the front tires are 25.5” in diameter so he has a difference if 0.7” in diameter which is good enough for the computer to function properly.
I believe Cray wheels are set up to bolt right on to our Corvettes, as long as you buy the correct wheel for generation.
If you are going to install C6 or C7 wheels on your car (which is what I did), the fronts fit just fine but you’ll probably want to run a spacer on the rear hubs. You don’t have to but the wheels will look sucked in. I put 20mm spacers on my hubs and the wheels fit nice and flush with the outside of the car.

Keep us posted on your search! Getting new wheels is exciting!!!
 
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The best 2 solutions I've come up with so far is - a chance to install a used set of good condition C6 wheels, so the info re the spacers is very useful. The other being a set of C6 Grand Sport aftermarket copies all around in 18" diameter with the difference made up in the tires as you mentioned. I'm leaning towards the C6 wheels mostly because they are original Corvette and they come as 18"/19" which is what I'd prefer. The Grand Sport wheels do look very sharp though. Maybe if I get them also as 18/19's I'd have what I really want.
On top of all this is the tire sensors. I'm guess I'm going to need new ones or go without completely. I'm assuming there is a way to turn off the computer tire warning?
 
Your current sensors should do the job..Sensors don't go off of the pressure is a little high... They just let you know when the pressure is to low. Stock tires and wheels on a C6 recommend 30psi.
 
There are awesome responses above ... mine may be I little different for you for the hunt ...
It's a long winter ... and if you are hoping for wheels that were optionally available for your car or even after market, keep an eye on
Detroit Wheel and Tire as they often get take-offs for after market wheels and then inspect, refurbish and resell used OEM (sometimes).
You can even call them and see what a salesperson might have collecting dust in the warehouse.
I bought optional GTX wheels about 10 years after the 1998 Ram Air Pontiac Grand Prix emerged. Detroit Wheel obtained them from
SLP and was reselling them rather quickly. Even with shipping and importing, my deal was sweet. You can possibly do a day-trip there
and back and pay the gst at the border (they will put new rubber on as well ... if you need). It's all about the exchange rate of course
but keep this source in mind for when our dollar is closer to par and you will realize great fortune.
Detroit Wheel and Tire
Check them out ... you will very likely see your C6 OEM wheels.
Even those new C7 owners out there that may wish to have the other wheels that were optional ... this place has them
 
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I have a set of stock '06 wheels with original tires collecting dust in my garage.
This is good to know. Good of you to mention this.
If you are cleaning out your garage of anything collecting dust and they fit a C6 (if '06) ;),
may I suggest you post specifics of them in the Forum as I know of at least 3 members in Alberta needing C6 rubber for the Spring.
I would like to let my friends know about your ad when it's posted ... or kijiji ad if you go that way.
Knowing your asking price is important as I know that new rubber quotations are already in hand. Thank you.
Parts for Sale/Wanted
 
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I had a c5 and I installed C7 wheels.Front goes on with no mods and for rear you need spacers and longer wheel studs.I forgot the size but I found it on US corvette forum.I had Manny to order and install them.
20161029_162901.jpg
 
Agree. Black on yellow - very cool. I like black wheels but I'm not so sure they would look good on Magnetic Red. Torch Red for sure but on darker colours they just don't contrast as nice except black on black of course.
 
Hi Ron!

I’m shocked I haven’t seen this thread yet.

You are correct about the different diameters between the front and rear tires. The computer likes anywhere from 0.5” to 1.5” smaller diameter tires on the front of the car when compared to the rear. As I’m sure you are aware, this can be done while using wheels that are the same diameter by using tires with a smaller diameter on the front either by a going with a tire with a lower aspect ratio or a tire with less width but the same aspect ratio such as what Murray has done. His rear tires are 26.2” in diameter and because he uses 275’s on the front instead of 305’s, the front tires are 25.5” in diameter so he has a difference if 0.7” in diameter which is good enough for the computer to function properly.
I believe Cray wheels are set up to bolt right on to our Corvettes, as long as you buy the correct wheel for generation.
If you are going to install C6 or C7 wheels on your car (which is what I did), the fronts fit just fine but you’ll probably want to run a spacer on the rear hubs. You don’t have to but the wheels will look sucked in. I put 20mm spacers on my hubs and the wheels fit nice and flush with the outside of the car.

Keep us posted on your search! Getting new wheels is exciting!!!

Where do you get 20mm spacers and what specs are needed to order them for a C5 using C6 wheels?
 
Ok, based on what I've read here and other forums, the C6 wheels will fit directly onto a C5 (stud pattern same) but because of the difference in offset on the front wheels, I would need spacer/adapters to make them flush with the fender edges or they will appear slightly inset. The rear wheels are no problem. Do I have it right?
Thanks
 
Correct. I used the term spacers when it should have been adapters. I found some on ebay and went with a vendor with a good rating. Just make sure you check the diameter your hub (Center bore). I ended up buying a wrong set because they said they fit Corvettes and the size of the hub was off by 0.2mm. You'd think it would still fit, but nope. So I got my money back but the problem was the spacers....er, I mean adapters cost $30 but the shipping, that you don't get back, was $70. C5 Corvette hub/center bore is 70.3mm.
 
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If your looking for some good wheels, that look amazing on Vettes. Check out Forgestar, we just got a set of CF10 19x10/19x12 in for a C6 Z06 and they were just amazing.
 
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