village idiot

Well, a true track tire won't be runflat, if for no other reason, there is no point. How often do you run over nails on the race track (although, I guess it just happened due to some construction at cota ). Track tires are typically very thin and light compared to a street tire.

Anyway, there is obviously too stiff and too soft, and a then there is personal prefrence. RF tires are probably way far into the "too stuff" (and heavy) category for a pure track tire, but that's not what the CUP2 is. It's a remarkable tire on the track. I just prefer other tires, they're expensive, they're heavier and I can't get them in a 315 front.

rico750sxi

C6Z wheels fit on C7Z or GS, here’s a link to a post covering the topic:
https://www.corvetteforum.com/forums...it-on-c7z.html

BlackMoon

Do you see any downside to running the non-run flat Cup 2s?

village idiot

I've never run them, but cost.

Poor-sha

Didn't we already cover this a few posts back? The Cup 2 ZP and the regular Cup 2 are different tires. The ZP was designed with the Corvette and you tell just by looking at them that the tread is different. I've driven a C7 Z51 with both the MPSS ZP and the regular MPSS and the ZP handled noticeably better. I'm talking from first hand experience here. Also see was Lasco wrote about his experience racing on the Cup 2 ZP.

You are correct that a true slick isn't going to be a run flat but they also are going to be designed for their intended purpose and you can't even say two tires from the same make are constructed the same. Here's a case in point. I've run the 315 and the 325 Pirelli DH slicks as a rear tire on my C7Z. You'd think that the 325 would handle better because it was wider. However, the 325 made the car prone to snap oversteer mid-corner and I couldn't get them off the car fast enough. After I dug in to this for a while it was because the 325 I was running was designed to be the *front* tire for the Viper in PWC. It's construction was different than the 315 that was designed as a rear tire. The result was the wider tire handled worse.

Sport Cup 2 ZP




Sport Cup 2




If you're not really pushing the car then buy what you like but you can't make blanket assumptions.

village idiot

I took it to mean blanket runflats, not C2 ZP vs C2- like how can any runflat be good.

Poor-sha

My apologies then. I agree that all other things being equal there's no need to use a run flat on track. In this case the other things just aren't equal.

BlackMoon

When the Cups came out for the Viper we were running the PS2 non run flats and everyone got excited and switched to the Cups. About half of the guys I knew including me switched back to the PS2. The cups were noticeably louder, less forgiving and didn't handle as well. That's the main reason I was exploring using a non run flat on the Z.

I've got MPSS on one set of wheels and the Cup2s I just got for the other set so I won't need tires that soon but like to research as much as I can before trying something. I'm not new to Vettes driving #20 but am new to tracking a Vette so I really appreciate everyone's input.

Here's to a fun and fast 2018. Thanks!
Sal

dp201

Most serious track guys run 18 inch tires all the way around and I'm just wondering if it's mainly the cost/available of tires issue or if there's any performance advantage over say a 19 inch square setup. It seems to me like having a smaller tire with more sidewall would lessen cornering ability compared to a shorte sidewall and possibly stiffer 19 inch tire. I realize that there are more and cheaper options with the 18, but I'm curious if there are other factors as well. Thanks for coming back.

village idiot

Less weight, lower cost, more tire options. Sidewall should be roughly the same height.

ncstingray

I think there is a weight savings to the 18" option.

BEZ06

A couple years ago I was accelerating through 140 mph around a left-hand sweeper in my C6 ZR1 when "ding ding ding". I looked down to see what the problem was and the DIC said I had a loss of pressure in the right front.

Wow - I sure was glad I was running on Sport Cup 2 runflats!!!!

Absolutely NO handling problem at all!! I can imagine what might have happened if I had a soft sidewall tire non-runflat. I know that when it just collapsed that if I didn't end up in the wall, I would have at least had some wicked handling upset to deal with!!

The exact same thing happened to a buddy in his C7.R SE Z06 last month. He was tracking out of a turn and accelerating through 90 or so on his Sport Cup 2's when he got notified the left front had zero pressure. He brought it in to the paddock and the tire looked fine, so he tried pumping it up but it wouldn't even hold 1 psi of air. He took the wheel off and found a hole (about 1" high and 2" long chunk missing) in the sidewall along the rim of the wheel. He may have run wide and dropped that wheel off a gator while tracking out which damaged the inside sidewall of the tire. With his runflat he just got notified of low pressure and drove it into the pits. With a non-runflat he may have ended up in a tire wall!!

I'm not racing - I just do HPDE type track events for fun. I used to run Hoosiers on my C6 Z06, but I'm not looking for podium finishes or a better pro driving contract. But I do find the Sport Cup 2 is a REALLY GREAT tire for the track!!

Just MHO, but I don't run anything but runflats on the street or the track. YMMV!!

.

2014GT

I usually run 18x11 front and 18x13 rear ccw's. Running Hoosier A7 315/345 f to r.

Best setup I've used on the track. It's exactly what I ran on my old c6z as well. The MPSS aren't great track tires, they do ok but don't like tons of heat. Mine are about to give up the ghost with about 4k miles on them.

dp201

Good testament about the added safety factor you get with the Cup2 ZPs.

rb185afm

Race mode still has nannies. I was having traction control kick in on triple digit corners, mid corner, as the car though I had exceeded the possible lateral grip, running R7 slicks. I was getting brake pulsing that caused my tires to impact my fender @ 110 mph lol. When I hold the button down long enough to kill all nannies, the high speed brake pulsing issue went away. Of note, I do not have a Z07, and I have no idea if the Z07 has a higher threshold or different parameters for traction control given its tires and springs.

2014GT

Race mode does not have braking nannies, only limited traction control. What you were feeling is probably the car cuttig power.

ShahulX

Yea, I think I will stick with stock Cup2 tires for my GS.. I did about 15 sessions this past year and they held up well.. they def were not as grippy as when new

AS for Zp vs not... the Corvette Cup2's are Spec 1448.. diff compound and tread... why called cup 2 still is beyond me...

I know this because I work for Mercedes and the AMG GTR comes with cup 2 tires that are reg cup 2's... but car and driver did the lighting lap with the spec 1448 vette tires and said its an option for the AMG GTR... not is the USDM

other than being slightly narrower (325 rear vs 335) the compound def makes a difference

Ive debated endlessly the cost of a new set of 18's for my car with R888r tires vs going through a set or two of cup2 (spec 1448) over the course of a year.

If I was able to do 10 track days a year, I'd switch...but with my work and family I can do maybe 5... I'll stick with my stock wheels I guess..

Im still using the CCB's also.. with stock pads and Motul RBF660. Has held up well but I think the stock pads only last maybe 10-12 sessions (track/driver dependent) are arent cheap.. debated switching to diff pads but worried about the life on the Carbon rotors

BrunoTheMellow

I am a testament to this, not just "feel" like everyone else but I have ran track days at the same track where the stock MPSS ZPs ran 2 seconds better on a 1:30-a-lap track than a hankook R-S3 with the same size specs. That's a huge time difference (granted the michellins run ~15 mm wider). The hankook R-S3 is a fairly respectable street/track tire. Still even with data to prove it, no one seems to believe me. I don't think anyone else on this forum has actually tested the MPSS versus other similar tires and taken quantitative data.

That's all i'll say, this is a wide body thread and although I'm trying to figure out track wheels/tires for myself, I merely have a narrow body, so back to miata width tires i go.

village idiot

They're still a street tire, but I've never had a street tire do that well on the track.

havasu486

So the most common HPDE setup is 18x11" front and 18x12" or 12.5" rear?

I like the Forgeline GS1R I just wish it was not so costly. You ahve a pay to play and we play an expense game.