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SuperdadZ06 do you know the age of your tires? Find the four digit number embossed on the sidewall. Let’s say: 4319. That would indicate the 43rd week of 2019, which is the last week of October.
This is the tire date of manufacture on my Stingray: first full week of November 2022.
I agree with your first statement but, with all due respect, Michelin (OEM tire manufacturer for C7s) disagrees with your conclusion/recommendation... "After five years or more in use, your tires should be thoroughly inspected at least once per year by a professional. If the tires haven't been replaced 10 years after their date of manufacture, as a precaution, Michelin recommends replacing them with new tires. Even if they appear to be in usable condition and have not worn down to the tread wear indicator."
You should do your own research and draw your own conclusions here, but Michelin is probably the most authoritative source on our cars' OEM tires, that they manufacture and sell.
NortonCO - I agree with you and I may have overstated the timeline. You are correct that Michelin is the ultimate authority. I base my timeline at 6 years due to personal experience and having a newly purchased C5 with 6 year old tires spin out under normal acceleration on a 45 degree day. Depending on how the car is stored also plays heavily into how the tires age.
We had a set of original factory Michelin PSS runflats and a set of Michelin A/S3+ runflats (two sets of wheels) that we alternated Spring and Fall. When they got to be six years old, both sets looked good and had plenty of tread but I followed our Owner Manual recommendation and replaced the PSS runflats with the same tires, and A/S3+ runflats with AS4 runflats because the AS3+ were no longer available.
The new PSS were a major improvement in grip, with some improvement also in noise and harshness.
The new AS4 were not as much of an improvement but it was still noticeable.
All three of our cars are now on a 6 year tire replacement cycle.
SuperdadZ06 do you know the age of your tires? Find the four digit number embossed on the sidewall. Let’s say: 4319. That would indicate the 43rd week of 2019, which is the last week of October.
This is the tire date of manufacture on my Stingray: first full week of November 2022.
This is why I love this forum. I had no idea you should replace tires every six years although I had been contemplating that. I also didn’t know a run flat can last hundreds of miles. I am in a 2019 Z06 running the oem Michelin run flats. I’d rather risk damaging a wheel with run flats than getting stuck on the side of the road. I will look into a fresh set of Michelins in the spring. My kid did help me inflate all four tires today and we took a nice ride. The Z06 is a lot of fun to drive.
The Michelin Zero Pressure tires only have the inner sidewall stiffened; the outer sidewall has the same construction as a non-run-flat tire. This was demonstrated to people who took the Ron Fellows C7 Corvette New Owner School at Spring Mountain. They had a cutaway tire and the outside sidewall was easily flexed using bare hands.
That is why the Michelin Zero Pressure tires have such good handling. When GM was setting Track Records with the Z06 they had the Michelin ZPs on the cars. On track, they handle as well as R-rated Street Tires such as Hoosier R7s and Competition Tires like Pirelli Slicks, although they don't last as long and are significantly more expensive.
The older C5 and C6 Goodyear EMTs had both sidewalls reinforced. The original C5 EMTs were very stiff and were rated for 250 miles of flat tire operation at speeds up to 50 mph (they could get you through some desert highway sections where there was nowhere to stop for 200 miles. The problem was that they handled terribly and gave runflat tires the moniker runcraps.
The Michelins may be noisier than a non-run-flat tire, but a lot of that has to do with the tread design and the road surface. The Pirelli Slicks I use for track duty make a lot of noise even with no tread. As far as performance, my Z06 with the stock ZPs can lap VIR at the same pace as it can lap with the Pirellis. However, I can purchase the Pirelli's used (no more than 2 heat cycles) for one quarter of the price of the Michelins and they will last about 40 more heat cycles (10 to 12 track days) before they cord, while I can only get about 10 heat cycles (2 to 3 track days) on the Michelins before they cord.
The ride quality depends on whether the ZP tire is a performance tire or an All-Season/Touring tire.
I sure appreciate Bill's detail and clarity. Thank you.
I moved to Continentals to forestall the dreaded rim cracking after Chevy replaced both rear wheels very early on in 2017. It worked. When I finally bought my BCForged 20x21 setup I moved back to the Michelin ZPs. I'm reminded every time I drive the car why I liked them more than the Contis. The turn in is significantly improved. Traction is better (especially when boost comes up, and I'm sure it helps that the rear are now 345/25/21 vs 335/25/20) and I just prefer the ride "quality" of the Michelins.
I did appreciate the improved wet weather traction, but I don't have much call to drive her in the rain. She's no fun in the rain anyway... usually just embarrassing. So for me, I'll be staying with the Michelins for the long haul.
I just swapped the 2016 factory run flats for Conti Extreme Contact Sports. I prefer the old run flats. These new tires are quieter and have a little more straight line grip, but the handling is much too floaty for my tastes. Car felt like it was glued to the road when tossing it side to side before, now it feels like a floaty eco car in comparison. Blah
I’m not a tech savvy guy and don’t know that much about tires but I have read quite a bit on the BMW forum about run flats with a lot of different points of view. The biggest concern for most BMW guys about run flats is lack of performance and reliability with bubbles being common. I have been on the fence about the topic and still have run flats on my BMW and my 2019 Z06. My Z06 only has 11000 miles and I have had zero issues with the tires but I do often wonder how much better the car would be with traditional tires. What’s stops me from flipping is feeling vulnerable about getting a flat far away from home with no solution. At least the run flats will get me 50 miles in most cases. I did buy a full size spare for my BMW from Modern tire to give me added security in the event of an issue. I live in the northeast where the roads stink locally and on the highway. I am wondering how many of you have gone away from run flats and if it’s been worth it.
My Ford Excursion had a spare wheel inside but it was securely held down. OP, are you willing to make such a mount to have your tire inside the cabin? I really don't want it coming loose and bouncing around but that's me. An observation I had was the new run flats felt so much better than the original. Those were from 16 or late 15. 8 years old. Compound hardens over time. So pretty much any decent tire is going to feel better than the old one you took off.
The last two times I have bought tires for a vette it was Michelin all season run flats and I'll do it again for my next set. They are loud and rough riding but with no spare I don't see a choice. But that's just me.
💯 % as well