I know, I know, I've read the posts detailing how much better non run flats perform compared to the original run flats on our C5's. Just curious if anyone has experience with modern run flat tires, like Michelin all seasons for example, are they better than they used to be? Currently I have non run flat Sumitomo's that the previous owner installed, and I carry a flat repair "kit" that I put together, but sometime in the next year or so, I'll likely be looking, so ...

 

I have installed Michelin A/S 3+ ZP. Their latest in run-flat tech. I had the A/S 2 that i replaced that were over 7 years old. They were hard and old. I read all the time how people went from old GY run-flats to non-runflats and how great the ride and handling is, NO KIDDING!!!. Guess what a big difference it is going to a new Michelin Runflat from the old one. It is always going to be better going from old tires to new. No matter what kind of tire it is. Yes i highly recommend the new Michelin A/S +3 RunFlat.

 

Just don't get Goodyear F1 EMTs and you'll be ok. Those tires are horrible.

 

A run-flat will never perform as well as a conventional high-performance tire, but the advancement that's been made over the last decade in run-flats has closed the gap a lot.

 

Run flats, by design, a stiff sidewall, to support a zero pressure emergency, will always be a poor choice.... run flat tires , by construction, will run much hotter than a softer sidewall construction. Run flats ride harder, and hotter, cooking the rubber compound until it is rock hard... ( known in the business as " work hard " )

As I've said many times... everything is a trade off. Want the safety factor of a Rub flat? you will be giving up ride, and tire longevity.
As Far as GY vs. any other manufacturer of run flats, there are no secrets... No one complains about GY run flats on a Brand new car.. No One..... the original GY run flats had a 200 mile zero pressure warranty. 2nd gen GY run flats had a 50 mile zero pressure warranty. 2nd gen was better than first gen. but then you gave up the safety factor of 200 miles for 50 miles... " Everything is a trade off.

Buy run flats ( any Brand ) and the life expectancy of the rubber compound to stay pliable without noticeable performance stability is about half of a conventional tire with a softer sidewall, and a much cooler operating temperature.

Its just how it is...Don't be fooled by those who buy New Run flats and say they are better. They are only better because they are New and have not been subjected to the heat that is associated with run flats. Run flat design coupled with 140 F. blacktop highways and road surfaces, will turn those New run flats into hard crispy critters, faster than you would like. Most people go into denial and put up with the eroding handling factor of hard rubber found with run flats that have been aged by above average heat which occurs naturally in any run flat tire because of its design..

I know a few things because I have seen a few things.

 

I got rid of the OEM Goodyear runflats on my '98 at less than 20k because they had become overly exciting on wet roads. Replaced with Firestone/Bridgestone (Firestone labels but Made in Japan on the sidewall) and they lasted well and were still grippy in the wet for a lot more miles. Replaced with Michelin AS/2's. Better than either of the previous makes both in grip and ride quality. Putting much less miles on these days, so they will probably get changed out due to age more than anything.

Stuck with run flats as when I do drive it usually involves very busy interstates and I want to be able to get away from the various sleepy or distracted souls out there before I try to pump up a tire. Especially at night. People get run into on the hard shoulders around here with grim regularity.

Besides, to paraphrase "Engines Charlie", what's good enough for General Motors is good enough for me - and all Vettes have had runflats as OEM since the demise of the C5 Z06.

 

Bill, why did all the smart People at GM decided to put run flats on these cars Knowing or not knowing that they were that bad? What was the thinking behind it? And they continue too do it today.

 

They are not that bad... you are just trading one thing for another... there is no room for a spare... people liked the idea... Gm uses former Corvette owners input in the design concept...

FYI... When you buy a Bugatti Veyron.. you had your choice of Michelin or GY run flats. they cost 24,000 dollars a set... yes 24,000. and they last anywhere from 15,000 to 24,000 miles. no room for a spare in a Veyron either. Of course it takes very special tools and a Bugatti field tech to change them...he comes to you...you pay all costs..

The problem with run flats is most people " think " conventional tires and all that goes with that. Since I left GM, I've been saying all along here on this forum.. " Everything is a trade off. " many people who choose run flats want the peace of mind and are willing to dump them at 20K because they are not 40,000 mile tires.

Lots of people are wanting conventional tire performance and longevity but with the added feature of run flat technology... Everything is a trade off. So that is not going to happen any time soon.

On a side note, my 58 fuelie Corvette got 12 miles to the gallon.. Corvettes are getting much better at this mpg thing... today. Sometimes technology can advance but it's fairly tough to bend the rules of physics.

The sun, UV rays, a Georgia black top road in Mid July with ambient around 101* F. and that road can fry an egg. Non flex sidewall construction of a run flat can multiply the cooking process to the point of increased internal psi of a tire by as much as 35 % over design spec, only adding to the heat, also decreasing the foot print due to over pressure... too many people check tire pressure cold... look at a run flat at operating temperature on a 95+ day and see where that 30 psi cold actually is. 38/ 39 psi, only adds to the problem. We tried to idiot proof this car and yet peoples still use low octane fuel, read the tire sidewall and put 63 psi in the tire because it says max pressure 63 psi. the idiots think that more " Has to be Better " GM spent a significant amount of R&D time and money to design an OLM system so your motor can last far past the certification set for an LSX motor, yet many do not use it.

Don't blame GM for making a world class car, that just too many people do not understand. Nothing out there compares dollar for dollar and what you get for that dollar.
Don't ask run flats to do what conventional tires do... they are not the same thing.

Lastly, no one buys a 70K C7 and goes back to the dealer bitching because their brand new car handles poorly because of the run flats.

 

Runflats are here to stay - GM, BMW and on and on. The current trend to "big" wheels for style rather than substance makes packaging a spare harder and harder.

RF's continue to get better. Give it another 10 years and non runflats will be the exception.

 

I love run flats. I have had three nails with one total loss of pressure and was able to drive home each time with no issues. Each time I had them patched also with no issues. I would rather have the run flat than a patch kit and try to do the repair on the road - potentially in the dark and/or rain on the side of the road - or think or my wife being stranded waiting for me to come out or calling for a tow.

 

I haven't used runflats for years....like regular non run flat tires....better feel and sound. Good luck!

 

I have Michelin pilot sport all season zero pressure run flats and they were good for the first year when new, (managed a 1.88 60'). But they really start to really SUCK down the road with some wear and the rubber gets hard, now they spin if i get on it in second gear over 3000rpm.
I can tell u my next set will NOT be run flats! Looking at toyo R888 or pilot sport cup2 or MickeyThompson's new cheater slics,
sorry for the hijack

 

I ran he Goodyear runflats for a while but the road noise and rougher ride led me to a switch to non-runflats. I have been using the Hankook Ventus V12 EVOs for a number of years and they perform so much better than the OEM runflats. But, if you are really concerned about getting a flat, the newer runflats are much better than the old ones were.

 

Those original Goodyear's gave runflats a bad name. I've had four different brands of runflats I currently have Pirellis. (sp?) I wasn't impressed by the PS2's. Expensive, noisy, and didn't last long. They are proud of that name, though. I think the best bang for my buck was Kumos. (sp?) I tried to get them again, but Les Schwab said they quit making them, so I didn't. These Pirellis aren't to terrible, though.

 

Give them time.. Run flats because of their design run much hotter than conventional tire.. heat is the number one destroyer of rubber.. rubber and carbon make up the tire compound.. performance tires get 60% rubber 40 % carbon.. touring tires get 60% carbon and 40 % rubber.. Tires get slightly different iterations of these formulas.. side wall construction is part of the heat aspect.. anyone with an infrared laser thermometer can check this out. I check out a Georgia Black top using thermal imaging and found that on a 90F +day temps were in the 140's/ 150 F range ON a similar note 134*F is the highest ambient temp ever record in the western hemisphere.. Death valley. try running those run flats at that temperature. they would be bricks in a week.

 

I just put non-runflats on mine (Continental Extreme Contact Sport). The ride is fantastic compared to the old Goodyear runflats. But then it should be, considering the old tires were the originals.

One stupid question - the garage only put 30 pounds in them. I thought they were supposed to be 32? I don't suppose 2 pounds matters much though. Pressure goes up a few pounds after they warm up.

 

my car had well worn michelin pilot sport as plus run flats when I bought it and they are horrible. Hard not to spin in 2nd and even broke em loose in 3rd (rolling into it hard to pass a truck on dry roads). Plan on putting hankook evo2 on soon as they seem to be best balance of price, traction, and longevity

 

Just saw nobody answered your question. You C5 tires are recommended to be at 30 PSI Cold, so the 'garage' did you right