I've seen some discussion where people have opted to not replace their tires with run flats.

Is it that big of a difference to run non ZP?
I'm going into my phase 2 and getting a YSi, headers, wideband, rear GT wing and tires.

A buddy of mine put a set of the Pilot sport 4s on his CTSV and it was a noticeable difference from the PSS. Buuuuut they do not come in run flat.
So my question is, is it ok to put non RF or does it hinder the performance?

Thanks!

 

I have a 2017 GS and just replaced the stock run-flat MPSS with non-rft Conti Extreme. The ride is softer, the interior cabin noise went down by about 1 to 2 db (using my phone app) on highway speed. No more tire skipping noise when getting out of garage. However, the performance of Conti is not as good as the MPSS. I have 4 track days on the Conti and they are not as sticky as MPSS and squeal a lot more. This is just my comment comparing the MPSS vs Conti as they are the only choices for the rear 335 tires. If you have the 285 in the rear, then you will have a lot more options.

 

I might go out as far as 295 on the stock wheels and if the ride is softer thats ok but i do not want to sacrifice handling abilities. If not then its PS4 for me. If it does then stock replacement is fine too.

 

The PSS ZP designed for the Corvette uses a different rubber compound than the standard PSS. It isn't clear the 4S is a better tire than the PSS ZP from a handling/performance standpoint as the standard PSS isn't as good as the PSS ZP. If you don't run the car hard (aggressive sporty driving isn't driving it hard) any performance difference more than likely won't be noticeable but the ride will be softer and the tire cost will be lower.

Bill

 

Oh i drive it hard. Not beating it mind you but how it was meant to be driven. At 20k miles my fronts are gone.It sounds from your statement that the PSS ZP seems to be superior to the non? Have not heard that.
From my exp with BMW, G8GT's,CTSV's, the PSS is better than anything else i have tried. Or at least suits my driving techniques best. But apple and oranges when it comes to comparing the same tire to those 2 completely different platforms.

I will probably end up sticking with the PSS ZP.

doing some major work to it and will be adding downforce to the equation now as well.

 

I work briefly in the tire manufacturing industry. Let me explain something that I learned in that very brief stint in my career.

Car manufacturers buy HUNDREDS of millions of dollars of tires from tire manufacturers a year. That gives them an incredible amount of leverage, especially if a tire company has an existing agreement with a car company. Often times during the development of a vehicle, a car company will have a specific tire size in mind for a specific tire brand and make, but need some features of the tires altered to meet a specific criteria.

For example (these are assumptions, not facts), when BMW came out with the E46 M3, they were equipped with Continental ContiSportContact II tires. However, during testing BMW was not happy with the tire wear due to the car's weight and bias toward eating rear tires (due to the ~1.5º of negative camber in the rear), and knew they would have trouble appeasing customers when they have to replace rear tires every 8,000 miles. So they went back to Continental and asked them to reformulate the tread compound to provide the same amount of initial grip, but a much better long term wear characteristics. The end result was, despite Continental having the same exact sizes to fit the E46 M3 before it hit the market (225/45/18F, 255/40/18R) in ContSportContact II tires, they made a special formulation just for BMW's OE fitment in the same size. The ONLY external difference between the tires are the compounds made specifically for BMWs have a little "N" marking somewhere on the sidewall.

The end result was mass confusion when it became time to replace tires for E46 M3 owners, as some who switched over to the none OEM 'N" spec tires from Continental experienced accelerated tire wear, but consistent tire grip and performance throughout the life of the tire. Those with the OEM "N" spec tires had tires that last up to 20,000 miles on their BMW, but grip would progressively drop until it hit the 2nd layer of compound Continental designed to last much longer (but sacrifice grip), so as the tire wore down, their performance suffered but it would take forever to wear off the 2nd layer of compound on the "N" spec tires.

That's but ONE example. There are numbers of instances where a car manufacturer just simply couldn't find the Goldilocks (or the baby bear) of the tire spec they need for a specific car, and would ask a tier 1 tire manufacturer to alter the closest tire they have on hand in order to meet their needs. Some of the criteria that a car manufacturer would ask to alter:

1. Price. This is probably the BIGGEST stickler. Most of the time a car company would simply ask for a price that is below the comfortable margin for a tire company, and this doesn't usually reflect the need for a new formulation, but is a HUGE driver in combination with other factors.

2. Wear. You see the example above with BMW and the ContiSportContact II tires.

3. Efficiency. Back when I was working in the tire industry, this isn't as common. But as more and more plug-in EVs come online, there's an increasing pressure for tire manufacturers to produce SOME of their higher performance tires to also have low rolling resistance to meet the EV demand.

4. Performance. This is more common on higher end performance cars, Porsche being the biggest drivers in this. A lot of common tire sizes have Porsche "star" marking on the side denoting that it's the factory formulation for Porsche OE, despite a common size being available for other cars.

5. Construct. As more and more cars are tuned and optimized to run run-flat tires, There are higher demands placed on OE tire manufacturers to provide tires with reinforced sidewall construct to meet the needs of zero pressure tires.

The Corvette is a bit of an oddball here. The Grand Sport, Z06, and ZR1 all ran tire sizes that are not common on other cars. So GM basically have some room to customize the compound and formulation for these fitment to their hearts content. Throw a dash of performance compound, with better wear rating due to rear wheel drive bias, and the NEED for zero pressure reinforced sidewalls, it's basically a set of tires designed by Michelin to specifically work only on the cars they came with. So while the tires may say "Michelin" and the models are "Pilot Super Sport" or "Pilot Cup 2," They're customized to a point where they are nothing like their non-runflat counterparts. Whether the Corvette specific tires are BETTER than their counterparts from other manufacturers is debatable, what is NOT debatable is that these two tires (PSS and Cup 2) are designed JUST FOR THE CORVETTE.

And judging from the ~1.45g of consistent max cornering force I logged while lallygagging on track with the factory Cup 2 tires, they are indeed stickier than your average tires that's for sure.

 

That's a very helpful post because I always wonder what are the differences between Spec N and regular tires. As for the C7, I now truly believe the RFT Michelin are optimized for the vehicle. I paid for the updated MRC calibration earlier this year and I notice that the initial performance enhancement from the MRC update was diminished (not completely) when switched to the Conti non-run flat in spirited dirving.