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Larger Tires and Widened Wheels on C6

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Old 06-20-2008, 03:01 PM
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Vito.A
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Default Larger Tires and Widened Wheels on C6

I just finished adding widened OEM wheels and larger tires to my C6.
The tires I am using are Michelin PS2 275/35-18 front and 305/30-19 rear. I actually ran these tires for several months on the stock wheels. For those of you that do not want to spend the time or money for wider wheels, these tires fit and work absolutely great on the OEM wheels. There is no rubbing and they fit inside the stock fender perfectly. Both front 275 and rear 305 tires mounted on stock wheels are outside the recommended wheel width by ½”; that is just ¼” per side. I spoke to the Michelin engineer and he said he could not recommend it, but it would probably be fine. I then called a friend that is a Discount Tire Store manager and he said it would be fine. Once mounted, you cannot tell they were not recommended for each other. They ride and handle great and are a huge improvement over the OEM Goodyear runflats. They ride so much smoother (the Z51 car actually rides smoother than a base car with runflats!) and the traction is great compared to the Goodyears. The 305/30 rear is .6” shorter than the original 285/35-19 tire. This required a minor correction to the speedometer. I emailed Mike at Diablosport and he adjusted my Predator tune and emailed it back to me free of charge. Thanks Mike!
I wanted to eventually go to 325 wide rear tires and thought I would search for wider wheels with the proper offset. Rules: I wanted the tire/wheel to fit inside the stock C6 fenders. I also will not buy wheels with rivets or bolts between the inner spokes and the outer rim section. I had a set of these on my last Corvette and I could never keep the brake dust cleaned out of the rivet section. The OEM Speedline wheels are a quality wheel manufactured in Italy and you would have to spend a small fortune to get anything better. I read Spinmonsters post on the strength of Weldcraft widened wheels and he is absolutely correct. We have used widened Weld wheels on the race cars for years and never had an incident. So, I decided widening the stock wheels was the best route for me.
I purchased a used set of C6 wheels from a forum member. I really wanted chrome 5 spokes, but they were priced higher than I wanted to pay. Also, Weldcraft (the company that widens wheels) charges a surcharge to widen chrome wheels because they have to grind the chrome off in order to not pollute the weld. So, I bought a set of OEM 5 spoke gray wheels really cheap. I sent them to James at Weldcraft in Plymouth MI. They charge aprox $200-250 per C6 wheel depending on width and finish. I debated how much to widen them for quite a while. I spent a lot of time measuring and spoke to others that have added wider wheels. In the end I stayed conservative and added ½” to the stock 18X8.5” fronts to make an 18X9” wide wheel and 1” to the stock 19X10” rear to make a 19X11” wheel. This will put me inside the recommended width for the larger tires and still keep everything inside the stock wheel wells. In fact, the minimum recommended wheel width for Michelins 325/30-19 Pilot Sport Cup tire is 11”, so when they come out with the new Michelin 325/30-129 PS2, I will be ready.
Weldcraft took about two weeks to do their magic. They TIG weld a strip of aluminum to the inside of each wheel all the way around. They need to add a min of 1” wide strip; anything narrower and it will distort. To widen a wheel only ½”, they machine an extra ½” out of the original wheel and add a 1” wide strip to the inside to make the total width increase ½”. They true up each wheel and guarantee their work. I received the wheels back from Weldcraft and they looked fantastic. We checked each wheel for runout and square, and they are all perfect.
Next on my list was to chrome the wheels. We tried stripping the OEM gray paint, but apparently it is powder coated. We soaked one wheel for a week in paint remover and it just made a mess. I ended up taking them to Nu Wheel here in Tucson and they sent them off to a chrome shop in CA. They easily strip powder coating and then triple chrome plate the wheels. This took another two weeks, but the results are nothing short of spectacular!
NuWheel mounted and balanced the Michelin PS2 tires on the OEM chrome widened wheels. Three wheel/tire combinations took .5 ounce and one took .75 ounces to balance out. They spin perfectly true on the balancer. They fit quite well with no rubbing anywhere and do not stick out of the stock fender. In fact, Weldcraft only adds width to the inside of the wheel, so the tire fits inside better now than it did with the stock width wheels.
After going through all this I would probably recommend adding a full 1” to the fronts. There is a ton of room up there and it would have been easier and saved $25 per front wheel. You can also add 1 ½ or 2“ to the rear wheels, but you will have some clearance issues. You can then use a spacer and longer wheel studs to clear the A-arm and the inside of the wheel well; or Gotcha used actually removed the inner liner section of the wheelwell and they fit great without spacers. With this setup you could even run the 345 rear tires, but they are going to stick out of the fender slightly.

My thanks to Spinmonster and Gotcha for plowing the way!

Below are some pictures to help visualize. The first two are on the stock polished wheels and the remaining are the widened chrome wheels. I still need to lower the car, but you get the idea.

Picture of 275/35-18 tire on stock width wheel



Picture of 305/30-19 rear on stock width wheel


Pictures of rear widened wheel





Picture of Front wheel widened



Picture showing how well they fit inside fenders

Picture from rear

Last edited by Vito.A; 06-20-2008 at 03:40 PM.
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Old 06-20-2008, 03:33 PM
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jogar80
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Great write-up!
Old 06-20-2008, 04:08 PM
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06.Z51.MontRed.Vert
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Great job, looks
Old 06-20-2008, 05:13 PM
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1SLOWC6
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Did you ever consider using the front wheels and placing them in the rear then widening them? I've thought about doing this cause there aren't that many drag radials for the 19's but 18 are a dime a dozen!

BTW it looks very nice!
Old 06-20-2008, 05:59 PM
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Vito.A
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1slowC6,
SpinMonster did exactly that. Do a search for widened wheels and you will find it.
Because the front 18" dia wheels require 2 1/2 inches added, and it is all added to the backside, it requires you to use an adapter to space them out properly.
Old 07-18-2008, 12:42 PM
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EdwardETraylorIII
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Guys,

I just found this thread after hours of searching - Here's what I need help with:

I can put either a 17" or 18" Drag Radial on the back of my C6Z06. I'm in a quandary on which tire/wheel combo to go with (17 or 18?).

I'm thinking the 17" OR 18" 345 @ 27-27.5" tall will net me the best results. The problem is finding the wheel to put it on. I would like to get a front C6Z (chrome so it matches all my other wheels) 9.5" x 18" wheel and have it widened to 12" so I can run the 18" DR on it and it will look like a stock-matching wheel. If I do this, will I need a spacer of any kind?

If the front and rear (OEM) offsets are the same, then I shouldn't need a spacer (and I want to avoid a spacer at all costs).

What do you guys think? Anyone know of someone you could recommend for widening of stock wheels?

I'm about to try Weldcraft. Any others?

OR I'm open to other recommendations as well - I just don't want to buy all new (front and rear) wheels. I love the look of stock - and I love a sleeper!
Old 07-19-2008, 07:48 AM
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Awesome!
So do you think 325s will fit with stock fenders?
That would be great. I had 275/315 on my camaro and loved it.
Old 07-19-2008, 07:54 AM
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C6 ROLLER
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Default Nitto's 305/35/18 DR

I had a set of aftermarket 18" rims on my car for awhile and the Nitto 305's Drag Radials fit under the stock rear fender but it was close to flush with it. I didn't widen anything but just took them out of the box mounted the Nitto's on them and drove away.
Old 07-19-2008, 08:18 AM
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Fascinating, great write up & great idea for those who want to appear stock
Old 10-01-2008, 08:43 PM
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Jimmyz28
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Default 19x11" ???

This is good stuff.

So is there any advantage to buying a 19x11 08 replica split spoke if I want a 305/30/19 tire on the rear?

I was told by a sponsor the 325 tire will rub badly on a 11" stock back spaced wheel.
Old 10-01-2008, 09:11 PM
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Originally Posted by Jimmyz28
I was told by a sponsor the 325 tire will rub badly on a 11" stock back spaced wheel.

If no spacers are used, a stock wheel widened to 11" with a 325 tire will rub the inner liner slightly. The liner can be trimmed or the wheel could be spaced out.

See my post about it
http://forums.corvetteforum.com/show...988&highlight=



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Old 01-20-2009, 06:10 PM
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Res1cue
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Originally Posted by Gotcha
If no spacers are used, a stock wheel widened to 11" with a 325 tire will rub the inner liner slightly. The liner can be trimmed or the wheel could be spaced out.

See my post about it
http://forums.corvetteforum.com/show...988&highlight=



-
How about the same configuration with 11.5 or 12" widen wheel with the 325. Will they still clear by trimming the liner? What would the max spacer be you could add to off set the wheel and not risk hitting the quarter panel?

Last edited by Res1cue; 01-20-2009 at 06:13 PM.
Old 01-20-2009, 07:53 PM
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C6 CYAA
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Originally Posted by Jimmyz28
This is good stuff.

So is there any advantage to buying a 19x11 08 replica split spoke if I want a 305/30/19 tire on the rear?

I was told by a sponsor the 325 tire will rub badly on a 11" stock back spaced wheel.
11" with 77-79mm offset fit great without rubbing. Some replica wheels only have a 65mm offset and will rub.
Old 01-20-2009, 09:55 PM
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Originally Posted by C6 CYAA
11" with 77-79mm offset fit great without rubbing. Some replica wheels only have a 65mm offset and will rub.

According to John at CCW, their rear 19x11 wheel has an 80mm offset and I haven't heard of anyone complaining of rubbing issues.
Old 01-21-2009, 12:17 AM
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SpinMonster
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Originally Posted by Vito.A
1slowC6,
SpinMonster did exactly that. Do a search for widened wheels and you will find it.
Because the front 18" dia wheels require 2 1/2 inches added, and it is all added to the backside, it requires you to use an adapter to space them out properly.
There is no spacer or adapter used with widened wheels because the distance from the hub to the fender is fixed and not changed from the widening process.

The thread:
http://forums.corvetteforum.com/c6-t...-solution.html
Old 01-21-2009, 12:31 AM
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Originally Posted by Res1cue
How about the same configuration with 11.5 or 12" widen wheel with the 325. Will they still clear by trimming the liner? What would the max spacer be you could add to off set the wheel and not risk hitting the quarter panel?
19" stock wheels widened.....

11" fits fine (actually grazes the control arm but not in use).

11.5" (touches the control arm when jacked up but again not in use)

12" touches and cant fit.

Last edited by SpinMonster; 01-21-2009 at 12:38 AM.
Old 01-21-2009, 05:58 PM
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Originally Posted by C6 CYAA
11" with 77-79mm offset fit great without rubbing. Some replica wheels only have a 65mm offset and will rub.

Yes an 11" rim with a 75 - 83mm offset works well. A 65mm offset is not good, it would stick out about an inch more than stock and probably make the tire hit the fender.





Originally Posted by SpinMonster
19" stock wheels widened.....

11" fits fine (actually grazes the control arm but not in use).

11.5" (touches the control arm when jacked up but again not in use)

12" touches and cant fit.

I agree with you that an 11" fits fine, and also that a 12" can't fit (without tubbing). You lost me on the 11.5" though

If an 11" wheel barely touches the control arm with the car jacked up / suspension unloaded, then where would the extra 1/2" go? You would hit the control arm 1/2" before the mounting face of the wheel would sit flush on the hub. An 11.5" would take some additional work (probably a spacer and some shock work) to clear the control arm.



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Old 03-03-2009, 05:24 PM
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The widening of the wheels is cool, but from what I have read, the 11's with correct offset will work, doesnt anyone make replica OE wheels at 11" and with the 77-83 offset, names would be great, I would love to get a 11" rear in the 5 spoke competition grey and mount up a 325 (and keep the stock fenders)? So what is the rear OE 10" wheel offset?
Unless of course I can find a super cheap pair of rears and do the widening!
Thanks!
Old 03-03-2009, 05:52 PM
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dennis50nj
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Originally Posted by 69and88
The widening of the wheels is cool, but from what I have read, the 11's with correct offset will work, doesnt anyone make replica OE wheels at 11" and with the 77-83 offset, names would be great, I would love to get a 11" rear in the 5 spoke competition grey and mount up a 325 (and keep the stock fenders)? So what is the rear OE 10" wheel offset?
Unless of course I can find a super cheap pair of rears and do the widening!
Thanks!
79mm
Old 03-03-2009, 08:05 PM
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pmj341
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Originally Posted by 69and88
The widening of the wheels is cool, but from what I have read, the 11's with correct offset will work, doesnt anyone make replica OE wheels at 11" and with the 77-83 offset, names would be great, I would love to get a 11" rear in the 5 spoke competition grey and mount up a 325 (and keep the stock fenders)? So what is the rear OE 10" wheel offset?
Unless of course I can find a super cheap pair of rears and do the widening!
Thanks!
Replica wheels are not as strong or as light as the OEM wheels
I have a set, still sitting in their boxes!!!!!!!!


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