hxrly

So the Nitto NT05 that I installed in March were down to the wear bars and I decided that I needed a bit more durability from my tires. Enter the Michelin Pilot Super Sports.



I decided to run 18s all around so I could rotate my front and rears. I have run Nitto NT05 twice and a set of Conti DWs before which were fantastic, but I was looking something with a bit more durability. The DWs would definitely give me durability, but the sidewalls felt a bit soft and made me miss the NT05s.

My research took me to other tires. I discovered the BFG Rivals, which run in 295/35, have fantastic reviews, and will probably be the new king of street/track compromise. However, the release date kept getting pushed back, and I needed tires pronto.

Then were the Pilot PS2s, which also came in 295s but the price was way up there. While looking at these I noticed that the Pilot Super Sport came in 285/35, so I did a bit of research and found out that not only the PSS are a newer, better performing version of the PS2, but they are also cheaper! I asked around here to see if anyone was running the PSS 285 in the stock 18x10.5 wheels, but no luck. I decided to pull the trigger anyways.







My fear was that the 285s would run small and it would stretch too much, but I'm really happy with the fitment. Another bonus is that the new tire on the 18" wheel weight only 2-3 pounds more than the worn NT05 on the 17" wheel. Also I've forgotten to turn off AH/TC a couple times and no crazy faults, etc.

More/better pictures upon request!

C5Z06NC

Just purchased the Michelin PS2's at $1680 installed...curious what the Pilot Super Sports ran you.

hxrly

Installed they were just over $1300, they are $292 per tire right now.

Hitman227

You're lazy if you drive with the smaller size in the rear, that's just the fact of the matter, in regards to the size of the tire. The percentage of greater traction you'll obtain will be exponential with biggers.

Solofast

Not to turn this into a urination contest, but your rank ignorance is showing again. Perhaps if you spent more time on the autocross and road racing section of the forum you would learn a bit more about a "square" setup and what benefits it has for folks that track their cars.

Provided the car is properly balanced with the correct roll stiffness he isn't giving up anything with this setup in terms of performance, and he now has the ability to rotate tires from the LF (which gets punished on road courses) and equal out his wear. Moreover, the bigger tires on the front will provide more front end grip, which is what the car needs. Once you have "enough" tire, whatever that amount of tire is, more tire doesn't provide more performance. Or, to put it another way, just slapping more tire on one end or the other, after a point, doesn't make the car any faster.

As an example, we've run Hoosiers on the car for autocross and track events. The 275-17's were just as fast as the 295's up front. You would think that that more tire = more grip, but that simply isn't the case. Once you have enough tire more just doesn't help.

hxrly

Thanks for saving me some of the typing. In short, this set-up works fantastic. Two weekends ago I was out on mountain roads keeping pace with GT-Rs, and last weekend I had a few compliments on how well the car handled on these tires at the autocross.

I read review after review and these tires are a fantastic combination of grip and durability for me. The 285s in the rear actually grip better than the 295 NT05s I was running before.

I couldn't be happier with the set-up, but of course if you think you need to go bigger than 285 on 18s then this will not work for you.

Couple pictures:

Hitman227

flyinlow427vette

Long term does this cause any issues with the electronics in the traction control?

Any effect on the speedometer? I assume it reads of the transmission?

hxrly

I've forgotten to turn off TC for miles and no faults so far. The speedometer should be the same if it's based off the rear wheels/transmission, as I am keeping the same tire height.

onspeed

Any loss in steering response/feel going from 265s to 285s up front? I think that's one reason manufactures don't run wide tires up front

hxrly

Keep in mind I went from 275 to 285 up front, so the tire compound is going to be the biggest change in this aspect. I did feel the front got a little heavier. The Michelin on 18" wheels were about 3 pounds heavier than the worn Nittos on 17"s.

The PSS have excellent steering response for a street tire. They can get really sticky once warmed up and with proper tire pressure. Ran them at 30 psi at the autocross and got up to about 35 with the heat, with 1.5 degrees of neg camber the whole contact patch was being used without any roll, etc.

racebum

wider is not always better. gone too far you actually drop straight line traction by having less weight per square inch

skyavonee

This line of reasoning doesn't make sense to me. If pressure is the important aspect (weight per area of tire on road, not tire pressure), then why not just run the narrowest tires you can fit on the wheels? This runs contrary to what most road racers and drag racers do.

And that graphic you posted isn't clear to me. What is the difference between the two on the right? Is one over-inflated and the other under-inflated? Or is there supposed to be a difference in wheel widths between them? I'm not sure what the take-away is supposed to be.

racebum

engineers spend a lot of time figuring out the optimum width for a given weight. the bigger things get the more unsprung weight you carry around as well

good discussion on it here

http://forums.corvetteforum.com/c6-z...-question.html

read all 3 pages

Toque

So your running 285/35/18 tires on all 4 corners of your car ?

Your active handling, and traction control are not going to like that.
Be sure to turn off your active handling and traction control.

Toque

skyavonee

Well yeah, there's the weight consideration, but my issue was with your initial claim in post #12. I didn't see anything in that thread that supports it.

I've seen countless people make this claim, but I've never seen an official-looking source verifying it, or a first-hand account supporting it. Have you? Just curious.

ktlocklear

I have zero issues as well. I've been running 315/30's squared on the track since spring. I ran 295/35's squared on the street for a while too with zero issues. Currently running 295/35 rear and 275/35 front on 4 18" Speedlines on the street with zero issues.

I just got a set of of Pilot Sports for my BMW M6 and getting them mounted tomorrow. Can't wait! Had a set of the Conti DW tires on it and got 29,000 miles out of them. I just put Conti DW tires on the Z.... Hope they last as long as they did on the M..... Time will tell I guess

racebum

contact patch shape. you pick this up in driving school long story short a narrower tire has a longer football shape contact patch. a wider one will turn the football more horizontal

think pounds per square inch. you can take a tire with no weight, look at what touches, add weight and see the change in patch

sometimes there is very little to no benefit to going wider. you just add weight and rotating mass

there's no real generalization that can be made, you just experiment with different sizes to see what turns the best lap

which of course is something we usually don't have the money to do so you buy what fits your wheels in the best compound available

this is a picture from a miata that tried various sizes. the big ones are 275 mm hosiers, smaller ones are 195.



see what i mean, smaller tire has a better contact patch even though the wider tire is capable of more G's due to a wider patch it has less to similar potential for acceleration traction and weighs a LOT more. you're talking a 9" wheel vs a 7" wheel and a few pounds on the tire. could easily be 7-10lbs a corner

back when i was really into street drag racing in 2000-2002...like before you went to jail for weeks for doing so i tried a lot of combos on a c4 and found 275-285mm tires were the absolute best for straight line traction. i literally tried 245 to 315 and that was the sweet spot.

Toque

I honestly don't have any specific documentation. Just issues people here on the forum have reported over the years. I have heard of a lot of people here over the years reporting issues with traction control. Usually they make a comment it started after replacing tires. After further investigation its discovered that they had chosen the wrong tire sizes (rear tire too close in diameter to the front tire size, or larger than the front tire).

The stock rear tire on a C5 has a 1.0" larger diameter compared to the front tire.
The stock rear tire on a C5 Z06 has a 0.7" larger diameter compared to the front tire.

Supposedly the C5 computer monitors the rotation of both the front and the rear tire. The computer uses the diameter difference in front and rear tire (seen above) in the calculation. If at any time the rear tire rotates at the same speed (or greater) than the front tire.... the computer assumes that you lost traction and turns on AH and TC. This is actually what happens when you spin your rear tires too. I don't know the exact numbers it uses in the calculation though.

If you do not show any issues with the same tire sizes front and rear that is maybe a good thing. It may also mean that your Computer is not working right. Maybe its something that a "tuner" can change in the program. Who knows.

Toque

autoxer6

This set up will work well. Good choice. You wont have any AH / TC problems on the street. It will be a little more active on a race course but you can just turn off AH. That is from my experience with square set up's. I love them.

I dont think you can go to big on a C5Z unless you are limited by wheel width. Street tires dont like being over stuffed on the wheel. 315 front 335 rear is about the limit on a C5Z with big wheels. But a 285 will still be nice. NASA time trial C5Z cars were setting track records on 255 stretched on a wide wheel. Size isn't everything, just one factor.