NOSLO6

With few sticky tires (treadwear < 100) available for 19" Z06 wheels I'm preparing myself to fork it over for Michelin Pilot Sport Cups.

BUT the Sport Cups' sizes don't quite match up to the stockers. The 325/30/19s will work fine for the rear, but the difference is larger in the front, where the choices are 285/30/18 or 295/30/18 vs. the stock 275/35/18.

HELP!: Has anyone run any of the above front Sport Cup setups on stock Z06 wheels? Does the rake look odd? Is the speedo error (+ approx 2% using online calcs) hard to live with?

Going to need some help to get the LS3 power to the ground, will have 475+ rwhp and a widebooty conversion by spring.

Thanks,
Scott

Sidebar: I spoke to Nitto's consumer relations dept yesterday and despite earlier comments there are currently no plans to release the NT01 or 555R2 in 19" sizes in 2008.

07MontRedcp

Maybe I don't understand your question but the front tire size will not effect the speedo.

BJK

Joe_G

You will have active handling problems if you don't keep the proper front to rear height ratio. Engine drag active will kick in, other active handling issues.

Spinmonster told me you can adjust the tire height for the rear with HP Tuners and that will take care of it. I know you can adjust tire height but I have never tried to fix the ratio problem. You might PM him for more help if he doesn't chime in - it it'll work then maybe you can run these tires.

SpinMonster

The ratio will work as is.

285 and 295 fronts are 25.1 and 25.2 repectively and the rear is 26.8.

As the rears wear more it will get into an exact ratio as stock. The only guys that have issues are those with less tire height in the rear with stock fronts and the rears get worn severely. Even then in HPtuners you can change the height of the rear to match the new front height for the needed ratio. If you use taller fronts and stock rears you tell the PCM you have taller than stock rears so it expects less revolutions from the front to rear ratio.

NOSLO6

The numbers you cite above are Michelin's published diameters for the Sport Cups (note for others: these are taller than what a tire calculator would suggest, but I trust the manufacturer...). The rear (325/30/19) is listed as 26.73.

Can you provide additional info on what the stock ratio the computer needs to see looks like? Any more technical info on what will cause the AH to foul up would be much appreciated-- I assume it's comparing tire rpms to fixed parameters, but haven't ever seen a good detailed discussion.

And thanks, this is very helpful.

0jhaines

The Michelin Pilot Sport Cup tires make an amazing upgrade for the Z06 Corvette if you are willing to live with the increased road harshness and tire noise (along with the significantly reduced tread life).

We installed a set on the vehicle Automobile magazine tested a couple of months ago. With stock alignment settings we still achieved very high cornering numbers - 1.07 g's in one direction and 1.04 in the other direction. With more negative camber the numbers would have been even higher (but street driveability and wear would have suffered).

The sizes we used on the stock 2006-2008 Z06 wheels were:

Front: 285/30ZR18 Pilot Sport Cup - MSPN = 81118
Rear: 345/30ZR19 Pilot Sport CUP - MSPN = 06610

We did not have any ABS or traction control related problems with this tire combination.

0jhaines

The base C6 Corvettes have a front to rear tire diameter percentage of 95.3 to 95.9% (the front tires are 95.3 to 95.9% of the rear diameter).

The Z06 Corvettes have a front to rear tire diameter percentage/ratio of 95.9 to 96.5%.

In the past we have been able to stay in the 94 to 97% front to rear range on the C6 and C5 Corvettes without causing any ABS or traction control related problems.

BLU-BY-U

you DO NOT want additional reduced life than the oem supercar runflat tires provide...it's already pathetic starting life at 9/32's, unless your tire budget is unlimited. To me, it's not - lol

however, they do grip pretty well once up to heat and my bolt on c6z makes 485/455 sae. I'd contemplate different rim sizes all together if that would open the possibility for more tire brand choices.

0jhaines

If you aren't in a huge rush and you want tires that aren't all out race tires, Michelin will be offering several Corvette replacement size tire options this year and one of those size combinations should fit the Z06.

They made some of that information public at the SEMA show. I expect them to make more information available after the Detroit Auto show.

NOSLO6

Jason,

Many thanks for this and the post on the ratio #s below-- fantastic detail. Extremely helpful and just what I was after. If I may, three quick questions:

1. How was tire to rim fitment of the 345s in the rear? Was the stock Z06 rear wheel (19x12) sufficiently wide?

2. Can I purchase the 345-30-19s from you/Lingenfelter? If not, from whom did you get these tires? Feel free to PM me with details.

3. I calculate the ratio for the 285 & 345 combo you describe as 92.28% (Michelin diameter specs of 25.1 / 27.2 = the above). This is a few percentage points lower than your safe range. Comments (or spot my error)?

Thanks--this is very helpful for me and I hope will be for others as well.
Nothing beats real world experience. And at the per tire cost of these things I don't dare guess!

0jhaines

1) The tire/rim fitment was fine. A 12 wide wheel is within the recommended width range for that tire. A 13" would be more optimal but a 12" works fine. If this was a front tire, then being at the recommended or widest wheel for the tire would be more important for handling/cornering.

2) Yes, you can purchase the tires from us. I know we don't have them in stock at this time but call our sales department and they can check on the lead time for you.

3) Yes, that Pilot Sport Cup combination pushes the envelope of front to rear ratio further than we normally do but we tested that combination prior to going to the magazine and did not run into any issues. The customer still has those tires on the vehicle and as far as I know, he hasn't had any issues either.

NOSLO6

Thanks once again for the feedback on my questions.

Thought I'd report for other potentially interested folks that the 345 Sport Cups are not yet available to the general public. A very helpful sales rep at Lingenfelter spoke with Michelin and though they will be producing them Mich. does not yet have an estimated production date estimate (price will be $628/tire). Jason, if you can get me a set I'll send you a very nice thank you card and put a big honkin' Lingenfelter sticker on my car.

325s are currently available.

Sigh, it was so much easier with my C5Z06's 18" wheels...

Wicked Weasel

I loved my MPSC (C5 295F/315R - no issues). I originally bought them as a back up for light wet weather track time, but then went another route for wet weather so I used them on the street when I took the car out. I loved the handling characteristics of the tire. Of course real pouring rain would be an issue.

If Michellin has something coming out that is more suited for the street I would be very interested in those. Right now I am running Nitto INVO which are ok, but not MPSC.

D1SMOOTHOPERATOR

anyone compare nt01's to the pilot sport cups?