Interestingly, higher tire pressures do ride slightly harder but not as much as you would think. I run 40 PSI on my DD with ZR tires-2001 Pontiac Grand prix (225/55/16 ZR) and 2008 Chrysler 300 (245/55/18 ZR's) and the ride quality is slightly harsher than 32-34 PSI...I never follow the car manufacturer door sticker recommendations since again from Michelin Techs conversation I had live with them noted above, those recommendations are NOT based on max tire performance parameters generally or max tire longevity and include ride quality parameters more than anything else.

I am surprised at the number of people who are driving or enjoy driving with either under or over inflated tires.....no flames.....
I guess driving for a living 3300+miles per week, (which includes the commute back & forth to work) there is no way I would drive with pressures that low or that high in my C3. I can even feel the difference in my big truck when the pressure is incorrect.....
But everyone has their own thoughts and feeling on this issue.....
just stay safe.....

20 PSI??

You are inviting sidewall failure and a blowout. Ask me how I know....

I run P215/70R15 tires. A bit firmer ride but it's a Corvette fer cryin' out loud! With a big honkin' 427 L71, 4.11 rear and no power steering, a bit firmer ride isn't an issue or even noticeable.

Okay, I'll bite. How do you know?

When I brought my vette home, I was just getting used to it and gaining confidence on the highway. Just as I was about to get it on a major road, I remember looking at the rear right and thinking 'damn, looks a little soft'..I took a reading and it was 20 PSI. BUT..the tire looked fine, just a few LBS low, you know what I mean? No harm I figured, Id air it up when I got home. Well, I never made it home.

The extra pressure on the sidewalls from the under inflated tires caused a blow-out that took out my the lower half of my quarter panel. (Almost 1K in body and paint repair)
Your tires call for 32-35 PSI for a reason. If you go substantially lower, the weight bearing surface switches from the tread to the sidewall.....trust me man, trying to crash land a Corvette with a blown tire at 75 MPH is NO fun. Neither are the body work bills.....

Your tire is certainly chewed up from driving on it when it was flat but what caused the the loss of air? A broken valve stem? A tread separation? A sidewall blow out? I've been running 20 psi in my 255X60R-15 rear tires every single day for 27 years and never had a failure related to low pressure because the rear tires on a C3 are only carrying about 800 to 850 pounds which is hardly anything.

Looking at your side pipes I think its entirely possible the sidewalls of your tires got severely overheated because of the proximity of the exhaust outlets to the sidewalls.

The sidepipe got dragged out about 2 inches because it hit the ground and was pulled. It was never installed real tight. (remember, I just bought the car). The exhaust was flared outward and had no effect on the tires. If you look at the picture you will see a white ring all around the tire, that where the weight had been bearing and finally given away. All Im saying is that 20 LBS PSI in a tire rated for 32 is WAY too low. If youve made it this far without failure, good for you. I run 30-32 PSI religiously.

I also had a 99 VW Jetta that had a tire failure with less than 30K miles on it. It was a lease, and I pitched a fit when they made me pay for towing and a new tire. When they pointed out that the remaining 3 tires were all 10-12 LBS low.....well, thats all the evidence I need to run tires at recommended specs.

Your results may vary. Seek a doctor if this condition lasts more than 4 hours.

In the 50 years I have been twisting wrenches I have never seen any tire that had an air pressure rating on it. I have seen maximum loads at certain pressures but never a minimum pressure rating.

Now back to my question: Where did your air escape? Broken valve stem? About 10 years ago there were thousands upon thousands of tire failures caused my Chinese-made valve stems suddenly breaking and the tire going flat in 2-3 seconds. I had two of them fail within three months of each other but both times I was only running about 30 mph and stopped before the tire was damaged enough to warrant replacing. Judging from the looks of your tire I'd guess you drove on it for a pretty good distance.

You say your side pipe got pulled OUT about 2"? That would mean it was 2" in further which would certainly overheat the sidewall.

Tires require a certain pressure in order to maintain the tire carcass integrity. In the picture above and in fact in the majority of tire blow out cases, UNDER INFLATION of the tire is the primary reason for catastrophic failure of the tire carcass. The reason that low tire pressure exponentially increases the possibility of a blow out is that low tire pressure INCREASES the heat in the sidewall of the tire dramatically...Heat is the enemy of any tire. As tire pressure falls, the weight of the vehicle will cause MORE tire sidewall flexing than under "normal tire pressure" and the flexing is what generates more than normal heat in a tire and eventually tire carcass failure. If you don't understand what I am saying, note the number of tire failures on a highway if there is a sudden drop in weather temperature from one day to another....The rapid drop in air temperature drops an all ready low tire pressure tire quickly to a dangerous level, generating excess tire heat, the result being blown tires on various cars. Same phenomenon with very high air temperatures and a marginal pressure tire, too much tire heat resulting from too low a tire pressure, excess tire heat is generated...result blown tires.

"Overinflation" (below the max tire pressure) mentioned by some is MUCH safer than under inflation...these terms are NOT interchangeable. As long as the tire's max pressure stays below the max tire pressure stated on the sidewall, the risk of catastrophic tire failure is at its minimum. The more pressure you can run/tolerate in a tire, the better tire longevity will be, better gas mileage, and a stronger tire...there is no argument on this issue...physics again....pesky topic if you don't understand the basics.

Which brings up a last point and something for everyone to think about...one of the main reasons besides performance that every car I own has ultra high performance all seasons or summer only tires is that these Z Rated tires (W/Y sub rating-168 MPH/186 MPH) are MUCH STRONGER tires than the traditional crap tires on most cars (S rated-112 MPH) and C3's. An S rated tire which is the minimum speed rated tire sold in the US, frankly, is total junk. The speed rating relates directly to the tire carcass's integrity (strength) and its ability to reject HEAT generation (theme here). A Z rated tire is MUCH STRONGER especially in its sidewall construction and will run cool as a cucumber at 80 MPH versus an S rated tire...it must run cool to be able to achieve its very high speed rating. The higher Speed rated tire will resist sidewall damage (bumps/potholes etc) MUCH BETTER than a lower speed rated one. My 2001 Pontiac Grand Prix has 225/55/16 ZR tires not because it can achieve 168 MPH (not even close) but for the traction wet/Dry, handling/Steering, and SAFETY over a S/T rated tire.

For sustained high speed running with a Z rated tire at or near the limit of the speed rating (168/186 MPH), the tire manufacturer will state in their official product info that said tire MUST be at the tire's max pressure on the sidewall of the tire...now why would they say that if "overinflation" is dangerous?

Hope this info is helpful and explains some of the myths around tire pressure.

You are forgetting two very important things and that is the load the tire will be supporting and the fact pressures are always checked COLD. The sidewall of my BF Goodrich T/A radial tires state their maximum load is 1885 pounds @ 35 psi pressure. Figuring my big block C3 weighs approximately 3900 pounds with a 53/47 weight distribution the front weighs 2067 pounds and the rear weighs 1833 pounds. So each of my rear tires are supporting approximately 900 pounds. As 900 pounds is only half of the rated maximum load of 1885 pounds only half the pressure is required which translates to about 17 psi when checked COLD. I run 20 psi COLD so as my car begins moving down the highway their air pressure increases and when I check them HOT they show around 24 to 25 psi. So you feel 24-25 psi HOT is under inflated? If I recall tire pressures are supposed to be checked when they are COLD or am I mistaken?

I have been running 20 psi COLD in my 255X60R-15's for 27 years and that 20 psi COLD gives me perfectly even tread wear. When inflated to near 30 psi COLD these wide tires will wear the center bald when there is still 1/4" to 5/16" tread on the sides which means they are being run way over inflated. Its the HOT running-down-the-highway pressure that counts; not the COLD sitting-in-your-garage pressure. But thanks for your lengthy explanation of tire pressures because some of the younger members of our forum still believe the MAX LOAD pressure is what their tires need.

I will have to agree to an extent with his statement that I outlined above in the second paragraph. When I purchased my 82 over 3 years ago, they had BFG T/A's on them and the rears looked as described, plus they were worn down. I replaced with the same exact tire and although they lasted me for over 50,000 miles they did the same thing more so on the rear tires as opposed to the fronts.
Just bought the same tires again a few thousand miles ago, but now made by Michelin, since they bought BFG. These tires now are constructed differently but keep the same appearance. And I have noticed an improvement in ride characteristics with the new compounds from Michelin.
That being said, on other tires that I have had on regular vehicles and on my previous Vettes, I have never noticed this tread pattern wear on any of them to my recollection. And as I stated before I always run 30 lbs pressure in my tires all of the time. So is this type of tread pattern wear as described just exclusive the "old" construction T/A's built by BFG when running 30 psi? And will this be eliminated with the "new" type construction from Michelin running 30 psi?
I don't know or have a clue, so stay tuned But getting 50,000 plus out of a set of tires on highway driving is pretty good no matter how they wear....

What I have learned from this thread is that people are going to run the tire pressure that they are most comfortable with regardless of what has been or not been posted here!!!!
Will repeat myself....whatever you do with your tires....stay safe...

Just have to add my .02 cents in on some of your statements...

I disagree that the "S" rated tire is total junk or less safe. With the exceptions of the vehicles I have owned that came with "Z" rated tires, I have never felt or had the need to change over to another size rim just to accommodate "Z" rated tires for speed or safety.
Not trying to "break them" for you, but I have never had a problem with a "S" or "T" rated tire ever!!!! Yes they will be "safe" to 112 mph, but how often do you obtain that speed on the highway. And I plead the "fifth", no comment... Just in my commuting back & forth to work I drive close to 23,000 miles a year. And my "S" or "T" rated tires roll great running down the highway. And again why would you run near the max pressure when you don't really need to unless you are at the track or running in a competition where you would see a benefit by running those pressures???
I cover my C3 nearly everyday at work, as always check the tires when covering the Vette. I have never felt excessive or any heat to speak of from my tires after driving 47 miles one way to and or from work, ever....so I will also disagree with your heat "theory" that the lower rated tires heat up more than the higher rate ones.....now if your running any type of competition, well that is another topic for another thread. But just using your C3 or any Vette for that matter as an occasional ride or as a "dd" like myself, I just don't understand running either to low or to high a pressure in tires.

Again, not trying to "break them" for you, just enjoying this thread, but also adding my .02 cents.........

Maybe my description of S/T tires as junk was a little harsh. Let me see if I can provide more clarity around my comments. I have changed over more than a few S/T tires to Z rated ones and in one case, the Grand prix, the exact same size tire and rim size as the OEM S rated tire (225/60/16 but I now run a 225/55/16 Z) and the difference in tire technology was night and day between the 2 tires. I did the same on my Chrysler 300 from an S rated 225/60/18 to a Z rated 245/55/18.../transformed the car from a marshmallow to a highway monster..BTW..the sidewall height of these 2 tires is exactly the same but one is very stiff and other is very soft. Same for my 78 from 255/60/15 S rated to 255/50/17 ZR...same sidewall height but much stiffer/stronger/better construction and they RIDE better than the BFG 255/60/15 by a country mile.

As for safety, yes there is a difference in tire construction strength, braking in the dry AND especially the wet, and handling and steering response (less sidewall flex). As for the speed ratings, as I mentioned before, they are NOT really about the max speed rating on the sidewall (112 MPH versus 168/186 MPH) but those numbers do tell you much about the tire carcass's integrity when stressed (strength) and the ability of the tire's heat rejection window of operation. Are S/T versus Z rated tires both black, round, and get you down the highway safely at 60-70 MPH? Of course, yes, but that is mostly what they have in common. A low profile tire (higher speed rating) must have much less sidewall flex than an S rated one to minimize heat generation...flexing creates heat. Higher pressures on any tire allows less sidewall flex and tread squirm and thus much less heat generation and better handling and steering response....you only have to swerve once to miss a deer or avoid an accident with a Z rated tire and you too will be a believer...

As for lower rated tires heating up more than Z rated ones..this refute is easy: Every tire sold in the USA must have 3 ratings mandated by the DOT: Traction, TEMPERATURE, and a wear rating. The ratings are pretty vague as an AA, A, B, or C rating. Most S/T rated tires are rated as temperature B (I just checked my BFG 255/60/15 S rated BTW). Every Z rated tire I have on my cars is A. So what does that mean? Answer, the Z rated tire will run cooler under the same conditions as the S/T rated one...no argument on this one. Another nod to safety, the Traction (this rating is for wet braking only) of the BFG C3 tire is A, all the Z rated ones are AA, meaning wet braking is better for the Z rated tire. Treadwear ratings tell the buyer that the higher number (500 for example) is very hard rubber great for wear, not so good for traction in the wet OR dry. Z rated tires that have extreme traction will be in the 200-300 range. In the early 90's ,as mentioned twice now, when I was obtaining my competition license to race, one of the courses I had to take was a high performance sedan driving course sponsored by Michelin and the Michelin field techs told not only me but the whole class about running as high a tire pressure on the street NOT racing on a track as your butt could tolerate (below the max pressure on the tire sidewall) for best handling, steering response, wear, and gas mileage on the street. Again, every Z rated tire manufacturer cautions that for the tire to achieve the max speed rating, the tire's pressure MUST be increased above typical pressures...read this:

http://www.tirerack.com/tires/tirete....jsp?techid=72

Higher tire pressures allow for less tread squirm and less sidewall flex and high speed rated tires are MUCH better at minimizing this phenomenon. Most people think that all tires are the same but I happen to endorse a tire for my daily drivers and high performance cars ones that are super strong (safer), have better traction in the wet or dry, and will cruise at 80 MPH all day long not breaking a sweat...those things equate safety to me. BTW- I drive about 25-30,000 miles per year as well and have for the last 25 years.

I appreciate your reply and can understand your comments and the article that you have provided. But unless you are out in the open and I mean open road where you can run at very high substained speeds, then yes all of your info that you have provided comes into good use. But on the average commute, even when you can achieve a high speed, it is not for any length of time, especially in my metro area.
Maybe it's me, or I am just getting old.... but if I run above 30 lbs pressure, I don't enjoy the ride and some of the roads don't help out in that department either!!!
As far as wet weather goes, what happens is a lot of drivers get impatient and don't slow or adjust their speeds to the present road conditions. Who is following to close to who and not leaving enough of a space cushion in any type of driving conditions... And that is when people get into trouble. Actually doesn't matter what conditions there are, if your not diving with some "smarts" you are asking for trouble.
The above line is referring to the general public and not one particular individual.
I don't have to be a believer.... my ZR-1 has Z rated tires.....
I am just saying that the average commute for me in my C3, 30 lbs is good enough for the drive. I can understand that with your competition experience, how strongly you feel about your tires. I do not have that type of experience. So for me with the type of driving I do with my commute, I am happy with what I have in whichever vehicle I am driving. That is not to say that someday down the road I would not upgrade to a different wheel and tire combo, but for now I am fine with what I have on my 82.
Enjoying the thread.....thanks for the info.....

All good...Thanks for your thoughts on this issue too.

Love the C4 ZR-1...almost as much as my 10 Z06...LOL

Another low, wow the : never stops. Entertaining though

You and I agree on something - wonders never cease.

Yes, all good.....

I was also thinking about a C5 Z06 which I really like, but always wanted a C4 ZR-1, and the opportunity arose. I did have a ride in a C6 Z06, and it was wild to say the least. And also out of my price range.....
And on a side note, just started the 82 and the 94 and top off the pressures to 30 psi....couldn't resist.... and took both for a ride....
One thing I do know is that we both along with others enjoy driving our rides whatever they may be, and that is what it is all about...

I run 34 psi all around on my 235/60R15 BFGs. Wear patterns look good, and the ride feels good to me.