fatsport

Anyone else done this? I fit checked my 18x12 rear with the short 335 Hoosier (25.6" Dia) on the front and it cleared fine on my C7Z. Looks like it will rub the inner liner under compression though.
Found this pic of a C6Z running them.

fair

The widebody C6 (Z06/GS/ZR1) chassis has room for 335mm fronts and 345mm rears, as you have seen in the picture you posted above. That was Jerry C's C6 Z06, which we did a bit of work to and I drove a couple of times at MSR Cresson (where I photographed these pics)



We have made dozens of sets of wheels for these cars in 18x12" fronts and 18x13" rear. There is usually a little rubbing of the inner fender fiberglass with a 335mm front, but the rears work without issue.



We have not been able to fit a 12" wide front on the front of a C7 Z06, though.



Hell, the stock front wheels don't even fit under the stock C7 "widebody" fenders, with GM having to use these little tacked on flares to try to squeeze more in there.



Here is a C7 ZR1 I photographed at MSR Cresson running an 11" wide fronts and 13" wide rears - the same he used on his C7 Z06. I'm pretty sure Kevin (the ZR1 owner) got these wheels from G-Speed, who is a regular contributor here.



That is pushing the limits of what anyone could consider fitting under stock fenders, and a 335mm tire you mention would really on worn on a 12" wide wheel - which would poke. Sorry bud - the C7 just cannot fit as much tire under the stock fenders as a C6.




And before anyone gets #Triggered about showing watermarked pics and vendor status, I'm also co-owner at Horsepower Research, which IS a paying vendor here. Just wanted to share what we have learned with about C6 and C7 wheel fitment.

Cheers,

fatsport

Great input, thanks!
Here's my 18x12 +50 offset fitting on the front. I fit a pair of these up a week ago. They clear lock to lock. As far as "poke" goes, they are basically identical to 18x11 +38. The center of the wheel is brought in 12 mm (50 vs 38) and then the wheel is 1/2" wider (12.7 mm) - so basically no change. The big increase is inboard. A good comparison for this the the TSW 18x10.5 +65 Lawdogg and others (Tool Hoarder) have run. On the ID side the 1" wheel is 3/4 " wider from center, which equates to 19 mm. It has 15 mm less offset (50 vs 65) than the TSW so that moves the inside edge back out 15 mm. The end result is 4 mm inboard of the TSW 18x10.5 +63. 4 mm is .156". or just over an 1/8". A very small spacer - 1/8" - would give the same clearance as the 18x10.5 +65.

I'll take my car for a drive with 335 front and the stock 335 cups to further test this out. This will only be a test, as 335/345 Hoosiers are the goal



18x12 335/30/18 front

BrunoTheMellow

Jeez with that ride height , nothing should rub.

fatsport

Ride height I went with for the track. Only about 1/2" higher in back than the front due to the short 335 R7s in the rear. The R7s are great on the street, as it's back in the 80s this week here.

BrunoTheMellow

That doesn't look bad. If you could grab a quick measurement to the top of front fender and rear fender I'd appreciate it! It's the same diameter as a stock tire give or take.

fatsport

Hoosier R7s are sized uniquely:
295/30/18 F has a 25.3" diameter - my car is right at 27" to the lower edge of center of the spat
335/30/18 R is 25.6" diameter - mine is 27.5" to the lowest inner edge at center of the rear fender

This leaves about 3 fingers of gap between the tires and the spats/fenders all the way around.

BrunoTheMellow

Thanks! The 335 was just a test? Okay.

fatsport

Yes, the 335 on 18x12 was just a fit check. Put one on and lowered my car down in the garage. Turned lock to lock and cleared easily.
Ran the 295F 335R combo at PBIR last night. With the smaller rear diameter tire the Z06 gearing was great - 5th gear was very strong on the back straight. The speedo being off by 3.8% was pretty odd though.
I'll get the 335 R7s on the front for a test ride on of these days. Definitely looks like the inner fenderwell will rub under compression though. Will need stiffer spring and/or swaybar.

C6WNC

I run 315/345 stock ride hight on my C6Z and get some rub on the front thru high G corners but not bad. The balance is very neutral on Oversteer / Understeer with the 315/345 setup. Not sure if the 335 up front would induce a little more oversteer due to increased traction.

CaddyRacer

Hey that's my Z06, well it was. I owned and tracked it for 3yrs. I had a lot of fun with this my FIRST Corvette.
I found a 2017 C7Z M7 deal I couldn't say no to

Post any questions
and yes Terry Fair of Vorshlag was my source for track setup (rims, brakes, safety, etc...)

X25

How did the 335 front test go? Hoosier 335 is a bit too wide, demanding a 12" wheel, but Toyo R888Rs' recommended range starts from 11.5", and I was wondering if I should try it out with my 18x11 ET38 wheels (along with 345/30/19 tires at the rear). I'm not worried about balance; Corvettes always seem to benefit from as big as you can get up front, but I'm worried about destroying fenders at the track : )

fatsport

I drove about 80 miles on the street with the 335 R7 on the 18x12 +50. Did fine except for a U-turn, when the tire contacted the rear connection point of the stage 3 aero pieces.
I did not try them on the track as I felt they would rub heavily under compression. I had read that lawdogg149 had rubbed quite a bit running 18x10.5 + 65 with 305/660 Pirelli slicks, and the 18x12 +50 was another 4 mm inboard. For another data point, my current 18 front is 18x11 +52. This puts the inside edge of my wheels 6 mm further out than what lawdogg ran. I have not had any rubbing, but have only run 305 Pirelli slicks up there. I have a set of 315/345 R7 scrubs mounted, will hopefully be running them next week
He and I do not have z07 springs though, I think that will help you a lot.

polyol

I rub with 315's on 11" wide rims and 2.5-degrees camber up front on the inner fender-well when turning and in compression. Full lock hits the front fender and certainly hits the brake duct cooler.

I added a 3mm spacer to see if I can correct the issue the next time I am at the track. Car is jacked up as high as I can. Just letting you know, if you want to run 12" with 335's you need them dialed in real good for offset, ride height and camber. Even then I think you will have to deal with rub under dynamic loads.

X25

I wonder if I should order 18x11.5 ET38 custom wheels, and see if 335/30/18s would work on my C7 Z06 Z07. I am almost certain that 335s will drop lap times up front, and 11.5 would hopefully help reduce chances of rubbing (I'm at stockish front height), and is only one step away from the minimum width recommended (12") for these tires. Hoosier already produces them at identical diameter to 315/30/18s, so we should be good on that end.

polyol

You could run a 335 on an 11" as well. Either way a wider tire up front will net better ET's 90% of the time.

X25

In my recent experience on Camaro SS 1LE, C7 Z51, and now C7 Z06/7, wider front always helped. 11" wheel is 1" away from the recommended range for the Hoosier tire, which makes me a bit concerned. Toyo's 335/30/18 tire has range starting from 11.5", but that tire is much taller, which probably helps in fitment flexibility. Hoosier's A/R7 335/30/18 has same diameter as their 315/30/18, which makes it very attractive to me, since that shorter than normal diameter for the spec will be invaluable to avoid excessive rubbing.

fatsport

I think 335s on 18x11.5” up front is a great idea. I’m sure they’ll fit. There’s a lot of inboard clearance, so I would go with +42 for 11.5” wide. I’ve run these 18x11 up front with 315/30/18 R7s with no rubbing.

http://www.stranoparts.com/partdetai...381&ModelID=47

X25

Since I last posted here, I asked Khoa (of Signature Wheels) if we can fit 18x11.5 up front, and he said they were barely able to fit one on a ZR1, which was not very confidence inspiring.

Then I contacted Hoosier, and asked if I could use 335s mounted on a 11" wheel. They said it would be pinched, and I'd likely have a bit of thread unused, but it should be safe. They also recommended swapping sides every once in a while to use the whole tire.

If we can indeed fit an 11.5" wheel, it would indeed make a big difference in my opinion. I think it could even make the 315s work better since R7 315s run wide. At this point, it just requires a brave soul to try it out. I already have 14 wheels for this car, and I'm a bit weary on buying yet another set of wheels, but I might.. one day..

bcpower

I run an 18x12 +40 with Hoosier 335-30-18 A7 on the front of my 2015 Z06 for Autocross. I did get a little rubbing from the wheel on the Stage 1 brake cooling pieces so I took those off. It took a lot of steering angle to rub on those. Other than that, no major rubbing. At least no more than the 305-30-19 mounted on a 19x10+40.