CeeSeven

C7 Z51: Want to go to 18" rims (for track) so I can get a better selection of track tires at a better price. Stock rims are 19x8.5 and 20x10.
I assume I can just get some 18x8.5 and 18x10 rims to make them physically fit in the wheel wells. But how do I spec the wheel to clear the rotor and caliper? I have a track friend who got some Finspeed 18" wheels for his C7 ZO6 and they cleared those big carbon/carbon Z brakes.
Is there really no issue as long as the bolt pattern and offset is the same as the stock wheels?

GTB/ZR-1

No issues w/ sizes. They normally have templates out there to be sure the rim spokes will clear the calipers. Also, be sure the rim will clear the front rotors as well.

Good luck & have fun.

Magister Ludi

Check this out:
https://www.corvetteforum.com/forums...s-sensors.html

I went with 18" wheels and am very glad I did. Rubber is cheap and plentiful. Currently running square setup of 295 Hoosier A6's. Really helps the car rotate. I have gone as wide as 315 in the rear without any issues, but front seems to max out at 295 or 305 depending on what tire is used. So far, I really like the square setup better.

CeeSeven

I read that other post. Never would have believed 18x10's front and 18x11's rear would fit on the car without rubbing issues with any tire that would fit on those rims. And 295's mounted on them is another thing I wouldn't have believed would clear air ducts and not hit the fender on turns. That's good stuff to know. Thanks.

Ever run BFG R1 tires. I hear they last longer and are more consistent than Hoosier's.

Edit: Didn't know changing rim size would disable TC, but I run in Track/Race, so it's disabled anyway, I guess. But do you have to look at some DIC message or will it go away and display your chosen display?

Magister Ludi

I haven't tried BRG's yet. Funny thing about the TC. After running the 18's a few times, it's no longer an issue. Car seems to have "learned".

The only rubbing is on the plastic air deflectors on the lower control arms. It carved a notch about 2" x 3". I cleaned it up a little with a box cutter. The Hoosiers are a little wider than the R888's & they also scrape a little on the inside edge of the brake cooling duct that comes in at the top of the wheel well. All of this rubbing occurs only at full lock. It doesn't seem to occur on the track.

I bought a set of 5mm wheel spacers, which seem to eliminate all of the rubbing. But they do bring the outside edge of the tires closer to the inside fender lip. I think it could be easily addressed with some more neg. camber, but I'm going to test the present setup with the spacers at an autocross next weekend. Still learning.

Magister Ludi

You might also want to check w/ Ben at Weapon X (forum vendor). They have much more real world experience than I do and some pretty interesting wheel packages to offer.

CeeSeven

Will do. Thanks.
Anyone else road tracking a C7 is welcome to chime in on their wheel/tire combinations who are pushing the limits of width.

Magister Ludi

Just to complicate things:

https://www.corvetteforum.com/forums...-question.html

https://www.corvetteforum.com/forums...z51-front.html

https://www.corvetteforum.com/forums...o-lift-it.html

Savage seems to have some hard won experience with these issues.

B Stead

Here's the most likely setup:

Front, 18 x 9.5, 56mm to 52mm, 265/35-18 tire or 275/35-18 tire
Front, 19 x 9.5, 56mm to 52mm, 275/30-19 tire
Rear, 19 x 11, 79mm to 73mm, 305/30-19 tire


The only reason for going to an 18/18 setup would be to run the short 315/30-18 tire. In the upcoming Rival S, that's a front tire and a rear tire. In the R888 there is also a 285/30-18 front and a 295/30-18 front.


Also, we know that a 315 tire with a 25.4" diameter and on a 10.5" wide wheel at 56mm offset, works on the front of the C7. The risk would be pushing for more diameter but then the tire width might be 295 instead of 315. In general, a 285 front tire calls for a 10" wide wheel, a 295 front tire calls for a 10.5" wide wheel, and a 305 front tire calls for an 11" wide wheel.


A 19/20 track setup is available in the Pilot Sport Cup 2 and the R888:

Front, 19 x 10.5, 56mm, 295/30-19
Front, 19 x 11, 56mm, 305/30-19
Rear, 20 x 11, 79mm, 305/30-20
Rear, 20 x 11, 79mm, 315/30-20

However the taller diameter tires might make the fitment more difficult.



If looking for a mild R-comp it's the R888. Also, the AD08 R and the upcoming Rival S are 200-tw tires that are very much like R-comps. I like the R-S3 available in the 305/30-19 rear tire size
.

FYREANT

are there any black 18" wheels that fit the rears properly, say no larger than an 11" wide wheel at most?

Magister Ludi

Not quite sure I follow all of that, but I'm sure it's just my limited experience. Just for comparison, my track wheel specs are:

Fronts: 18x10 +58
Rears: 18x11 +79

(Camber may also be a factor: fronts are -2.0, rears are -1.7)

FYREANT

Yup for drag racing. Much more options for slicks in 18". I'll check out the options you listed. Thx

CeeSeven

OK. I'll be chewing on that one a while. But thanks.

B Stead

The bottom line is that the 305/30-19 rear tire size is well supported and that at about the correct tire diameter.

305/30-19

RE-11
Pilot Sport Cup 2
R-S3
AD08 R
R888 (r-comp)


315/30-19

Hoosier R7 (r-comp)
.

Magister Ludi

FYI:

I just noticed that the Corvette Store on this site has a Wheel Configurator for all corvette generations, incl. the C7. Worth checking out for those looking to purchase wheels.

skxf430

Has anyone considered running a 265/35-19 and 325/30-19 combo for road courses?

This combo has a very wide selection of tires including the RE11's, AD08R's, Super Sports, Sport Cup 2's, R888's and Hoosiers.

Ben at Weapon X said the 325's in the rears fits without any issues.

Higgs Boson

325 fits with a +86 offset or more...If you are lowered don't plan on 325s, IMO, especially at high G corners. You need to pull those wheels way in so they don't rub the fender lips.

skxf430

Yes, I plan on lowering the car slightly, so I might be better off with a 245/35 and 305/30-19 combination. Those sizes still have quite a bit of tires to choose from too.

B Stead

It should be 285 front with 325 rear.

And 265 front with 305 rear.

I wouldn't go more inward on rear wheel offset than 79mm and that means forget about the 325 rear.

The 315/30-19 on an 11" wide wheel looks okay at 79mm rear wheel offset. But none of the top tires are yet offering it.

The 305/30-20 might be a problem on lowered cars with wheel offsets around 74mm.

It's the 305/30-19 on an 11" wide wheel at wheel offsets of 79mm to 74mm. This is the most likely setup.


If an extra-wide tire is wanted, it's the AD08 R but the sidewall is extremely stiff:

AD08 R in 305/30-19
12.2" section width
11.8" tread width
(Run this one at 79mm rear wheel offset and hope that it doesn't rub. It is shorter than a 325/30-19.)

R-S3 in 305/30-19
12.3" section width
11.4" tread width

Sport Cup 2 in 305/30-19
11.0" tread width

RE-11A in 305/30-19
12.2" section width
11.1" tread width
.

skxf430

B Stead,

You are like an encyclopedia!!!

What width wheel and offset for a 265/35-19?

Thanks again.