1996 LT4 C7 rims
Thread Starter
Racer
Joined: Jul 2016
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1996 LT4 C7 rims
So I just bought a set of C7 rims that I thought were C6 at the time. I have searched and searched and I cannot find anything definitive on what size spacers I need. A few people have said 1" front and 1.5" rear, but that applied to C6 and not C7. We tried to, "mock up" using washers but the suspension makes the rear wheel positive camber so much when jacked up that I cannot trust the measurements. They are the common silver 5 spoke, 18x8.5 and 19x10. GM part numbers are 20986434 and 20986438. I would have thought surely by now, with all the take offs in circulation, this info would be in the FAQ of all the top Vette sites but BOY WAS I WRONG!
The plan is to get Hub Centrict adapters then have them and the rims powder coated together.
The plan is to get Hub Centrict adapters then have them and the rims powder coated together.
Team Owner
Joined: Sep 2003
Posts: 25,394
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So I just bought a set of C7 rims that I thought were C6 at the time. I have searched and searched and I cannot find anything definitive on what size spacers I need. A few people have said 1" front and 1.5" rear, but that applied to C6 and not C7. We tried to, "mock up" using washers but the suspension makes the rear wheel positive camber so much when jacked up that I cannot trust the measurements. They are the common silver 5 spoke, 18x8.5 and 19x10. GM part numbers are 20986434 and 20986438. I would have thought surely by now, with all the take offs in circulation, this info would be in the FAQ of all the top Vette sites but BOY WAS I WRONG!
The plan is to get Hub Centrict adapters then have them and the rims powder coated together.
The plan is to get Hub Centrict adapters then have them and the rims powder coated together.
Confirm them and I doubt you'd have issues.
Thread Starter
Racer
Joined: Jul 2016
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Looks like you nailed it!
Team Owner
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Post a snapshot of the back-side of the wheel flange where it meets the rotor surface!!! I would think the 8.5 and the 10 should be the same. If NOT then both!!
***Never mind if it's an issue because I believe that there should be depressions between each wheel stud bore on the wheels.
***Never mind if it's an issue because I believe that there should be depressions between each wheel stud bore on the wheels.
Last edited by WVZR-1; Aug 8, 2016 at 03:59 AM.
Team Owner
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Everyone has a different opinion on tire/wheel placement in the wheelhouse so what I might think appropriate you very well may NOT and Joe, John, Jim & Dick might have other thoughts!
Off the shelf adapter/spacer style a minimum required thickness for stud accommodation is generally thought to be 19mm (3/4') - so that's your least possible choice unless you wanted to use a pass-through, most don't like and in some areas may NOT pass safety inspections.
A 1" off the shelf when used on the rear would "boost" the wheel "outer edge" out something greater than 4mm (pretty much replicating the OE fit 9.5 + very little).
The fronts are actually a "direct bolt on" when compared to base cars but if you wanted to correct the outer wheel edge to match a 9.5 front you need 13mm+ and since a pass-through is very undesirable by most then an off the shelf 3/4" would make the front wheel edge nearly equal to the NEW REAR PLACEMENT(-4mm)
Joe, John, Jim and Dick might suggest others and I've NOT done this on a later C4 so it requires thought maybe.
USER "QCVette" has likely done similar to a later C4 and he'll stop by I'm sure this AM.
Off the shelf adapter/spacer style a minimum required thickness for stud accommodation is generally thought to be 19mm (3/4') - so that's your least possible choice unless you wanted to use a pass-through, most don't like and in some areas may NOT pass safety inspections.
A 1" off the shelf when used on the rear would "boost" the wheel "outer edge" out something greater than 4mm (pretty much replicating the OE fit 9.5 + very little).
The fronts are actually a "direct bolt on" when compared to base cars but if you wanted to correct the outer wheel edge to match a 9.5 front you need 13mm+ and since a pass-through is very undesirable by most then an off the shelf 3/4" would make the front wheel edge nearly equal to the NEW REAR PLACEMENT(-4mm)
Joe, John, Jim and Dick might suggest others and I've NOT done this on a later C4 so it requires thought maybe.
USER "QCVette" has likely done similar to a later C4 and he'll stop by I'm sure this AM.
Last edited by WVZR-1; Aug 8, 2016 at 04:50 AM.
Thread Starter
Racer
Joined: Jul 2016
Posts: 299
Likes: 15
Post a snapshot of the back-side of the wheel flange where it meets the rotor surface!!! I would think the 8.5 and the 10 should be the same. If NOT then both!!
***Never mind if it's an issue because I believe that there should be depressions between each wheel stud bore on the wheels.
***Never mind if it's an issue because I believe that there should be depressions between each wheel stud bore on the wheels.
Team Owner
Joined: Sep 2003
Posts: 25,394
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Yes - with the depressions if the stud extends beyond the 3/4"(19mm) spacer then the depression will absorb very likely the length. If you need to cut off some of the "pilot" you'll have no issues.
Pick your favorite wheel offset calculator and compare 10 @ 52.6 and 8 1/2 @ 37 for maybe an idea of the fitment for WHEELS ONLY using the outer wheel edge. Tires complete the package and sometimes need to be considered along with wheel offset.
Pick your favorite wheel offset calculator and compare 10 @ 52.6 and 8 1/2 @ 37 for maybe an idea of the fitment for WHEELS ONLY using the outer wheel edge. Tires complete the package and sometimes need to be considered along with wheel offset.
Last edited by WVZR-1; Aug 8, 2016 at 04:49 AM.
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Thread Starter
Racer
Joined: Jul 2016
Posts: 299
Likes: 15
Everyone has a different opinion on tire/wheel placement in the wheelhouse so what I might think appropriate you very well may NOT and Joe, John, Jim & Dick might have other thoughts!
Off the shelf adapter/spacer style a minimum required thickness for stud accommodation is generally thought to be 19mm (3/4') - so that's your least possible choice unless you wanted to use a pass-through, most don't like and in some areas may NOT pass safety inspections.
A 1" off the shelf when used on the rear would "boost" the wheel "outer edge" out something greater than 4mm (pretty much replicating the OE fit 9.5 + very little).
The fronts are actually a "direct bolt on" when compared to base cars but if you wanted to correct the outer wheel edge to match a 9.5 front you need 13mm+ and since a pass-through is very undesirable by most then an off the shelf 3/4" would make the front wheel edge nearly equal to the NEW REAR PLACEMENT(-4mm)
Joe, John, Jim and Dick might suggest others and I've NOT done this on a later C4 so it requires thought maybe.
USER "QCVette" has likely done similar to a later C4 and he'll stop by II'm sure this AM.
Off the shelf adapter/spacer style a minimum required thickness for stud accommodation is generally thought to be 19mm (3/4') - so that's your least possible choice unless you wanted to use a pass-through, most don't like and in some areas may NOT pass safety inspections.
A 1" off the shelf when used on the rear would "boost" the wheel "outer edge" out something greater than 4mm (pretty much replicating the OE fit 9.5 + very little).
The fronts are actually a "direct bolt on" when compared to base cars but if you wanted to correct the outer wheel edge to match a 9.5 front you need 13mm+ and since a pass-through is very undesirable by most then an off the shelf 3/4" would make the front wheel edge nearly equal to the NEW REAR PLACEMENT(-4mm)
Joe, John, Jim and Dick might suggest others and I've NOT done this on a later C4 so it requires thought maybe.
USER "QCVette" has likely done similar to a later C4 and he'll stop by II'm sure this AM.
Rolling these up next to the '96, the 18" fronts are noticeably shorter than the stock 17's and will unfortunately lower the ground clearance, the 19" rears noticeably taller. I hope this doesnt cause ABS issues?
There is an identical set for sale locally, without tires. Im tempted to purchase and try to run the 19x10 on the front too. Do you think that would fit without clearance issues? Looks are important but so is cornering. I intend to try a few auto crosses with a friend and will probably put a pair of bias ply slicks on the stock 17's for occasional drag runs.
Team Owner
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I'm not a 19" wheel on a C4 fan but some do look very good on the '91+ cars, on the '90 and earlier definitely NOT. Tire sidewall height that's required for tire dimension compatibility doesn't excite me.
Some have mentioned ABS/ASR issues if you "tinker" to extremes the tire dimensions front/rear.
I'll leave my comments to just offset/spacer and wheel "outer edge" LOL
Some have mentioned ABS/ASR issues if you "tinker" to extremes the tire dimensions front/rear.
I'll leave my comments to just offset/spacer and wheel "outer edge" LOL
Thread Starter
Racer
Joined: Jul 2016
Posts: 299
Likes: 15
I'm not a 19" wheel on a C4 fan but some do look very good on the '91+ cars, on the '90 and earlier definitely NOT. Tire sidewall height that's required for tire dimension compatibility doesn't excite me.
Some have mentioned ABS/ASR issues if you "tinker" to extremes the tire dimensions front/rear.
I'll leave my comments to just offset/spacer and wheel "outer edge" LOL
Some have mentioned ABS/ASR issues if you "tinker" to extremes the tire dimensions front/rear.
I'll leave my comments to just offset/spacer and wheel "outer edge" LOL
Team Owner
Joined: Sep 2003
Posts: 25,394
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I appreciate your opinions and input very much. Just to make sure I understand you correctly. 1" in the rear will result in nearly the exact outer rim to fender lip placement of the stock setup but 4mm further out. Then I can just bolt on the fronts but they will lack the +4mm so wont look exactly like the rears correct? If I go the minimum 3/4" front adapter instead of a 4mm pass though spacer, I end up another +4mm outward from the 1" adapted rear?
If you wanted to do a pass through on the front then you would need a 13mm on the front to place the 8.5 outer edge where a 9.5@56 would be (25.4/2 rounded up) - the wheel hub flange won't allow a 13mm pass through and maintain any hub-centric. I have done 16mm pass-through and was able to create a hub-centric.
3/4 adapter/spacer on both ends works very well also. Maybe buy a pair of 3/4 and do both on one side? Try that and then if you wanted the +1/4 for the rears buy 1" pair OR another pair of 3/4 if those made you happy.
Do you have a "local" vendor OR is this going to force an Internet order? Maybe post a WTB/borrow in the parts section. Where are you located?
Last edited by WVZR-1; Aug 8, 2016 at 06:06 AM.
Thread Starter
Racer
Joined: Jul 2016
Posts: 299
Likes: 15
No You need no pass-through when using the 3/4 front/1 rear, that combination makes the outer wheel edge very close when both are used.
If you wanted to do a pass through on the front then you would need a 13mm on the front to place the 8.5 outer edge where a 9.5@56 would be (25.4/2 rounded up) - the wheel hub flange won't allow a 13mm pass through and maintain any hub-centric. I have done 16mm pass-through and was able to create a hub-centric.
3/4 adapter/spacer on both ends works very well also. Maybe buy a pair of 3/4 and do both on one side? Try that and then if you wanted the +1/4 for the rears buy 1" pair OR another pair of 3/4 if those made you happy.
Do you have a "local" vendor OR is this going to force an Internet order? Maybe post a WTB/borrow in the parts section. Where are you located?
If you wanted to do a pass through on the front then you would need a 13mm on the front to place the 8.5 outer edge where a 9.5@56 would be (25.4/2 rounded up) - the wheel hub flange won't allow a 13mm pass through and maintain any hub-centric. I have done 16mm pass-through and was able to create a hub-centric.
3/4 adapter/spacer on both ends works very well also. Maybe buy a pair of 3/4 and do both on one side? Try that and then if you wanted the +1/4 for the rears buy 1" pair OR another pair of 3/4 if those made you happy.
Do you have a "local" vendor OR is this going to force an Internet order? Maybe post a WTB/borrow in the parts section. Where are you located?
P.S. Apparently im going to have to find another option than Amazon for 3/4". They seem to only have 1" and up. I guess I can just get a set if 1" for the rear and just bolt on the fronts for now?
Thread Starter
Racer
Joined: Jul 2016
Posts: 299
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I went ahead and just ordered from http://www.motorsport-tech.com/
They dont stock what I need and forge them to order so I just went ahead with your .75 front and 1" rear recommendation. I figure I can first put the .75s on one side (front and rear) like you said. Then switch over to the 1" rears and decide whether to stay that way or sell the 1" and buy a second pair of .75. Thanks a bunch for your help! Ill post pics once installed.
They dont stock what I need and forge them to order so I just went ahead with your .75 front and 1" rear recommendation. I figure I can first put the .75s on one side (front and rear) like you said. Then switch over to the 1" rears and decide whether to stay that way or sell the 1" and buy a second pair of .75. Thanks a bunch for your help! Ill post pics once installed.
Thread Starter
Racer
Joined: Jul 2016
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Here are some pics after install. I had to take just under a 1/4" off the front studs as they hit the back of the rim voids. Im going to run them for a while and see if they grow on me. They are sticking out the slightest bit and im not sure if they will rub on big bumps or not. The rear worked out perfect! The fender well spacing is perfect now, but I may end up lowering the rear some to make up for the lift from the rims, to level the car back out some. I already have to back in my garage to clear the air dams and now the front is lower than stock.
Team Owner
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I'd say you've done well, snapshot #1 and #3 seem to indicate that. #2 looks like maybe the fronts aren't square(pointed straight ahead) tweaked a bit left(steering wheel not quite centered). I'm guessing that you just did the all four mount when you realized the pilot needed trimmed for the 3/4".
I did the 3/4 - 1 based upon generally less expensive off the shelf and didn't "tweak" anything. The fellow I bought spacers/adapters to spec from has passed and I'm reluctant to suggest others. I had seen a rant regarding he vendor you chose sometime ago. How would you rate their product? They used to be seemingly higher than what I was accustomed to paying but I had a "relationship" with the guy I used.
If you decided to tweak the fit some the vendor you chose does "to spec" also so you could resell the 3/4 or 1 OR both and tweak the fit if the product seemed to be a quality product.
I did the 3/4 - 1 based upon generally less expensive off the shelf and didn't "tweak" anything. The fellow I bought spacers/adapters to spec from has passed and I'm reluctant to suggest others. I had seen a rant regarding he vendor you chose sometime ago. How would you rate their product? They used to be seemingly higher than what I was accustomed to paying but I had a "relationship" with the guy I used.
If you decided to tweak the fit some the vendor you chose does "to spec" also so you could resell the 3/4 or 1 OR both and tweak the fit if the product seemed to be a quality product.
Last edited by WVZR-1; Aug 12, 2016 at 06:49 AM.
Thread Starter
Racer
Joined: Jul 2016
Posts: 299
Likes: 15
I'd say you've done well, snapshot #1 and #3 seem to indicate that. #2 looks like maybe the fronts aren't square(pointed straight ahead) tweaked a bit left(steering wheel not quite centered). I'm guessing that you just did the all four mount when you realized the pilot needed trimmed for the 3/4".
I did the 3/4 - 1 based upon generally less expensive off the shelf and didn't "tweak" anything. The fellow I bought spacers/adapters to spec from has passed and I'm reluctant to suggest others. I had seen a rant regarding he vendor you chose sometime ago. How would you rate their product? They used to be seemingly higher than what I was accustomed to paying but I had a "relationship" with the guy I used.
If you decided to tweak the fit some the vendor you chose does "to spec" also so you could resell the 3/4 or 1 OR both and tweak the fit if the product seemed to be a quality product.
I did the 3/4 - 1 based upon generally less expensive off the shelf and didn't "tweak" anything. The fellow I bought spacers/adapters to spec from has passed and I'm reluctant to suggest others. I had seen a rant regarding he vendor you chose sometime ago. How would you rate their product? They used to be seemingly higher than what I was accustomed to paying but I had a "relationship" with the guy I used.
If you decided to tweak the fit some the vendor you chose does "to spec" also so you could resell the 3/4 or 1 OR both and tweak the fit if the product seemed to be a quality product.
Instructor
Joined: Jul 2016
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From: Plymouth MI
They look great!
Just a shame to hear GM is making the new Corvette rims in Mexico though.. Never thought I'd see that! Canada maybe, but Mexico? Usually it's Fords who send most of their stuff to Mexico, and GM to Canada.
I blame NAFTA, but the rims really pop on that green color!
Just a shame to hear GM is making the new Corvette rims in Mexico though.. Never thought I'd see that! Canada maybe, but Mexico? Usually it's Fords who send most of their stuff to Mexico, and GM to Canada.
I blame NAFTA, but the rims really pop on that green color!
Thread Starter
Racer
Joined: Jul 2016
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Thanks! Yeah I was a little surprised. The original plan was to powder coat them a dark burnt bronze and I have considered repainting the car a satin platinum or graphite. But it looks a lot less boring than I thought it was going to be, originally!