Installing Wide Tires on a C8 Stingray

[HotRed98]

This is for anyone who is interested in installing wide tires on a C8 Stingray. I have a 2021 Stingray with factory wheels. I replaced the Factory the 245 front tires with 285/30 ZR 19" and replaced the 305 rear tires with 335/25 ZR 20". The new tires are Michelin AS 4. I like the wider tire look. I had no problems with clearance. No problems with steering wheel effort. No CEL's.

After installing the wider tires, I have installed 20mm spacers and still have no clearance problems. It gives the car a "Hot Wheels" look. The tire tread is still under the body line. Clearance wise I only get a slight rub when turning sharp out of a steep driveway (very doable). I have been running this setup 8 months daily totaling 5000mi.

I have added a Lingenfelter Carbon PTR intake manifold with Soler 95/100mm TB and Soler throttle controller.
I installed the Halltech CAI C8 Hornet air cleaner system.
The Lingenfelter "Kit" is complete with everything needed. I am real happy with the setup. No CEL's.

I would be glad to text or email photos to anyone. The car is real fun on the street and the wider tires help it hookup better. After dragstrip tracking it twice, I may need sticker tires for the dragstrip.

If you're going to start pushing it,, be sure to add the 2 extra quarts to the transmission oil, change the transmission oil filter before 7500 mi and turn off the T/C.
I also use the MOA engine oil additive and change the engine oil/filter at 50%.

Regards,
Hot Red 98

 

[Cannonball Rally]

Interesting you installed the lingenfelter " Alien " intake manifold, is the juice worth the dough? It's an amazing set up, about 3 grand but does it actually deliver better performance?

I can only assume you do not have Front Lift, if you did would the wider tires still rub on hard turns?

Where are the photos to prove the end result? What was the final $ spent to achieve this new look?

Thanks

 

[Nik]

This is for anyone who is interested in installing wide tires on a C8 Stingray. I have a 2021 Stingray with factory wheels. I replaced the Factory the 245 front tires with 285/30 ZR 19" and replaced the 305 rear tires with 335/25 ZR 20". The new tires are Michelin AS 4. I like the wider tire look. I had no problems with clearance. No problems with steering wheel effort. No CEL's.

After installing the wider tires, I have installed 20mm spacers and still have no clearance problems. It gives the car a "Hot Wheels" look. The tire tread is still under the body line. Clearance wise I only get a slight rub when turning sharp out of a steep driveway (very doable). I have been running this setup 8 months daily totaling 5000mi.

I have added a Lingenfelter Carbon PTR intake manifold with Soler 95/100mm TB and Soler throttle controller.
I installed the Halltech CAI C8 Hornet air cleaner system.
The Lingenfelter "Kit" is complete with everything needed. I am real happy with the setup. No CEL's.

I would be glad to text or email photos to anyone. The car is real fun on the street and the wider tires help it hookup better. After dragstrip tracking it twice, I may need sticker tires for the dragstrip.

If you're going to start pushing it,, be sure to add the 2 extra quarts to the transmission oil, change the transmission oil filter before 7500 mi and turn off the T/C.
I also use the MOA engine oil additive and change the engine oil/filter at 50%.

Regards,
Hot Red 98

Appreciate the info and first post.

I've redacted your phone number. You don't want to post a phone no in a public forum.

 

[Jack Raccoon!]

Am I suppose to subscribe or click the button below for this? Asking for a skeptical friend....

 

[Cityfisher]

feel free to post some pics in here.. Just **attach.
I think id do the same, well one set for track + new set with Michelin AS 4 ina bigger size for the rest of the year.

 

[HotRed98]

Appreciate the info and first post.

I've redacted your phone number. You don't want to post a phone no in a public forum.

OK. Thanks.

 

[Afterimage]

What wheel width are the stock C8 wheels? FYI, a 335/25/20 has a recommended rim width range of 11.5-12.5" your factory rear wheel should be a 20x11. Is there some tire bulge happening on the rear? You speedo is also reading slower than your actual speed by 1.47% so your overall mileage will show lower than your actual driven mileage.

Alloy Wheel & Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit

Alloy Wheel & tyre fitment calculator - it calculates inset, poke, speedo error, tyre stretch and loads more.

www.willtheyfit.com

Also on the front, should be 19x8.5" and a 285/30/19 tire has a recommended rim width of 9.5-10.5" should be major tire bulge there on the front.

Alloy Wheel & Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit

Alloy Wheel & tyre fitment calculator - it calculates inset, poke, speedo error, tyre stretch and loads more.

www.willtheyfit.com

From my checks on the net Z51 wheels are 19x10" +43 and 20x12" +59 these wheels suit your new tire sizes better as they are basically C7 Z06, GS wheel sizes running the same size tires that you are running.

 

[Murray20c8]

feel free to post some pics in here.. Just **attach.
I think I'd do the same, well one set for track + new set with Michelin AS 4 in a bigger size for the rest of the year.

Ya, I'd like to see pics. Ontario has tire laws that restrict how much tire is exposed. In fact I believe, (Someone will correct me if I'm wrong, I'm sure lol) that the top of the tire can not stick out past the fender. Or at least by a certain amount.

 

[Afterimage]

That's the reason -camber was invented.

 

[DenisC8]

I would not do what OP is suggesting that he did, there is way more engineering involved than "it fits, with a little big of rubbing and scraping"

if someone wants a bigger contact patch, I would suggest running a wheel/tire size from Z06/E-Ray with a custom offset to fit the standard Stingray body work.

 

[Afterimage]

Run the Z51 wheel sizes then you can run those tire sizes, granted you'll gain a lot of unsprung weight going this route with the larger tire and wheel width but that can be mitigated by forking out large sums of moneys for lighter forged/ CF wheels.

 

[Murray20c8]

I would not do what OP is suggesting that he did, there is way more engineering involved than "it fits, with a little big of rubbing and scraping"

if someone wants a bigger contact patch, I would suggest running a wheel/tire size from Z06/E-Ray with a custom offset to fit the standard Stingray body work.

Contact patch never gets bigger unless the construction and material in the tire changes. All else being equal a different tire size changes the shape of the contact patch. Wider tires mean the contact patch gets wider and shorter, meaning straight line traction will decrease while cornering traction may increase. Also a wider front tire means there will be much more tire wear on the inside and outside edges when cornering.

 

[HotRed98]

My wheels are OEM stingray wheels. 8.5" x 19" front and 11" x 20" rear. Yes, I know they're not as wide as the recommended widths.
Also, keep in mind these wheels are spaced out an additional 20mm. It works for me. Laws are different in OK.
Remove the spacers, keep the 245's on the front and the tires tuck inside the body line, no rubbing, ever.

Besides, how often do you make a center-to-lock 90 degree turn out of a steep driveway?
No spacers on the front and they don't touch under any driving conditions.
I run 30 lbs front and 28 lbs rear. Don't knock it unless you've tried it!

5000 daily street miles and 2 dragstrip days. NO problems. The 335 tires hook good. Keep the engine OEM stock and you probably can't break the 335's anyway. With my engine mods, I can launching off idle.

My last street car was a C7 Z06 that ran 10.0's @ 140mph w/18" M/T ET Street drag radials @ 17 lb, spaced outward for 7 years and a tread wear rating of "0". You couldn't nail it on the street with OEM tires.

This car and this setup are a lot more fun as a street car. As a drag racer for over 60 years, I've had a little practice.
Hot Red 98

 

[DenisC8]

Run the Z51 wheel sizes then you can run those tire sizes, granted you'll gain a lot of unsprung weight going this route with the larger tire and wheel width but that can be mitigated by forking out large sums of moneys for lighter forged/ CF wheels.

Z51 and non-z51 C8s have the same size rims and tires

 

[Afterimage]

You are correct, don't know why the site I use to check wheel specs show the wheel sizes I mentioned earlier.

 

[Afterimage]

I like my tires to be mounted on wheels either in the middle of the rim width recommendation or the max. wheel width for street/track driving (track meaning road course). I understand your setup for drag racing you would want a little bit of bulge so the tire can flex when you launch it. I can see the tire bulge with the 335 tire on the 11" wide wheel (you're only 0.5" off the minimum recommendation for that size tire).

Your 285 front tire mounted on a 8.5" wide wheel is more of a concern (1" under the minimum width). Some tire places here most likely would not mount a tire that wide on that narrow of wheel, front end cornering at speed would make the sidewall squirm too much and behind the wheel can feel weird as there is little to no support for the tire sidewall from the narrow wheel.

 

[scraze66]

I’m sorry but this does not look good. Reminds of some C8s with bad fitting cheap aftermarket wheels which stick out giving it a 4x4 look. Tires should never be sticking out of the fender wells especially on a sports car.

 

[DenisC8]

My experience with my 10.0 sec, C7 Z06, I made my best 1/4 mile times with the rear tire air pressure in my 345/R30 18" M/T ET Drag Radials at 16 to 17 psi because the tire path gets both wider and longer Front-to-Rear. And the front 285/30R19's at 50psi to decrease rolling resistance.

With your education background you should know better, or at list know that you don’t know enough. The changes you made may improve your “drag racing” times but will negatively affect other performance metrics that corvette engineers spent years perfecting as well as wreak havoc on the cornering ability and how the car behaves once you go over the limit of those abilities. It will also mess with traction control’s ability to save you when you lose it.

Even if your only goal is 1/4 mile times, then you still did it wrong by using the wrong tire and wrong rim.

I encourage everyone to watch this video:

 

[HotRed98]

I like my tires to be mounted on wheels either in the middle of the rim width recommendation or the max. wheel width for street/track driving (track meaning road course). I understand your setup for drag racing you would want a little bit of bulge so the tire can flex when you launch it. I can see the tire bulge with the 335 tire on the 11" wide wheel (you're only 0.5" off the minimum recommendation for that size tire).

Your 285 front tire mounted on a 8.5" wide wheel is more of a concern (1" under the minimum width). Some tire places here most likely would not mount a tire that wide on that narrow of wheel, front end cornering at speed would make the sidewall squirm too much and behind the wheel can feel weird as there is little to no support for the tire sidewall from the narrow wheel.

I agree with your comment regarding the front tires. I relied on a major, long time, Dealer (the expert) in this area and his opinion was the setup would ok for street driving and drag racing.

Having done it, I'm going to use them up. Then I'll go back with probably a 245. I don't do any autocross, only straight line drag racing and street driving.

I'm considering narrower "Front Runners" for drag racing anyway. If I can find a wheel I like and use up the 285's for street driving. The wide front tires don't help for drag racing.

I strayed from my point in my original post. That is, I PROVED, it is IS possible to run wider tires on the C8 stingray without special wheels or ANY clearance problems. The rest is a matter of personal preferences, car use and local laws.

My all time favorite wheel was the chrome, 2019 ZR1 wheels which I ran on my 10.0 sec C7 Z06. Too bad GM changed the lug bolts to 14mm.

In closing, I would run 345's on the back of my C8 Stingray if they made a suitable tire in 20".

 

[HotRed98]

60 years drag racing experience , then maybe you can tell me, why does my 2023, HTC, Z51 wheel hops, often. Even does it at the Napierville track in Quebec Canada, with compound. I even tried drag radials, with lower air pressure , around 22 pounds and still it bunnied/hop, sorry raccoon . I think I figured why it hopped, with the original tires , run flats , but drag radials should not hop! I have seen C8s , completely stock, go 11.17 quarter mile at this drag strip, so what is your take on this.

I have experienced some wheel hop on launch. (Not using Launch Control, Mine bogs with Launch Control and then takes off). My car is a 2021 Non Z51. Sometimes it hops. Sometimes it doesn't. I launch off idle because I don't want wind it up and dump the clutch.

I've had 2 track days with 4 passes total. (Someone blew an engine and scattered oil/antifreeze on track and I left because I was worried about the cleanup.) 2 of the drag strip passes were with a 3/4 full tank + 120lb rider (1/8th mile). It didn't hop with a rider and all the run data was slightly better up to the 1/8th mile. 1.84 sec 60' time.

I've also done a number of street launches (thru 1st and 2nd only) It probably hops 1 or 2 times out 10 launches. It launches hard on the street.
Although my hops are very momentary and not severe, they're a concern. They're infrequent, short and I've usually been powering thru them. I'm running 335/25 R20 Michelin AS 4 run flat rear tires.

As I understand it, a hop occurs when a tire breaks & makes traction. Probably a function of the (size & rubber compound), spring rate, road surface and shock valving. Most of those items are not easy to change.

I've played a little with tire pressure.

Higher pressure will make the tire harder and it easier to "blow" the tires and probably not hop. This isn't a good solution.

I've been trying lower pressure of 26 to 28 psi on the street. This seems to help. I lowered tire pressure to 23/24 lbs on the track and that seemed to help. On the street, no two stop lights have the same road surface condition.

If I had an email or other alternative, I could send an MOV of my track run that hopped and another without hop.

Past experience, my 2011 supercharged Gran Sport and my 2015 10sec Z06 NEVER hopped.
My 2007 non-supercharged Z06 ALWAYS hopped unless I launched with higher torque (called slipping the clutch) and blew the tires. A base car could have beat this car always off the line. I never tracked this car (except on the street).

My '62 Fuelie, '79 L82, '93 Non-Z automatic (But with the 315 tires), '98, 2005 corvettes and my '66 Nova SS 327/350 (215/62 R15 radials), all NEVER had wheel hop.

I don't have a good solution for C8 wheel hop. Keep tweaking the tire pressure. I'm launching off idle.

Here's night shot of my C8