Hmmm....
I've never actually had a tire "blowout" on me without some sort of debris causing the problem. Usually within the first couple weeks I own my new tires I pick something up
Get's kinda frustrating, but I've come to expect it. Heh, these new Nitto NT450 Extreme's I have seem to be bucking the trend.
As far as non debris related blowouts, my 195/70R14 tires on my 88 LX's were stressed much more from tire rollover during hard cornering. The sidewalls were scuffed significantly and they were beginning to develop large patch bubbles on the sidewall from damage. Those tires could have actually experienced a blowout had I kept driving on them.
My best piece of debris was picked up on some 195/60 HR15 Escort GT tires, I think that was the size anyway. A valve stem, yes, that's right. I picked one up right in the middle of the tire, core side in. The stronger belting didn't help me too much there, but I would agree with
Mr. 5.0's theory that stronger is better when it comes to debris resistance.
Also worth noting is the way the car handles with a flat tire. Take a normal 205/70R15 tire and blow it out. There's going to be some MAJOR handling problems, and you'll likely know the tire is blown right now. On a high performance low profile tire, it's a lot harder to tell if the tire is low or flat. The extra strong belting and sidewalls mask the problem. It's important to check your air pressure on high performance tires because of that reason. It's hard to tell when they are down by looking, or driving. Too bad the tire can still tell as the inside belting will be destroyed in short order, and could potentially cause a catastrophic blow out.
On the technical issue of speed ratings, I thought it had to do with heat dissipation rates, not actual temperature ratings. The actual temperature the tire can endure is listed on the sidewall under Traction (AA, A, B or C) and Temperature (A, B, or C). Traction refers to wet road stopping ability, and temperature relates to resistance to high temperatures. Of course, Treadwear is also an issue. On a high performance tire with a softer tire compound you might see a treadwear of 180-220 (BAD), and on a touring tire, I've seen treadwear rating as high as 400. Treadwear isn't directly related to tire life expectancy. It's related to how fast the tire wears. On a tire with a deeper tread, a 300 treadwear tire might outlast a 320 treadwear tire with a shallower depth. As tire technology advances, you might find a higher treadwear tire like my Nitto NT450 Extreme's to be a better traction tire than the old 220 treadwear garbage Goodyear Eagle (gatorbacks). Here is a real question. Why in Kell's name does Ford still put the Eagle's onto the Mustang? The GT's rolling off the line are using a tire that was designed nearly 20 years ago, and came from the factory on my 1987 GT. Pathetic. The Eagle's have a horrible reputation for wet traction, and are mediocre at best when it comes to traction in the dry. Adding to that, they have horrible treadwear and life expectancies. With all the tire ruckus, you'd think they'd put a good tire on the GT, anyway.
Here is a breakdown.
P245/50 VR16 Traction A Temperature A Treadwear 300
P stands for passenger car (LT stands for light truck)
245 is the width of the tire in mm
50 is the aspect ratio, meaning the percentage of tire width that the tire is in sidewall. This tire has a 123.5mm tall sidewall.
V is the speed rating (149mph)
R stands for radial belted tire
16 is the rim size.
Traction A stands for the distance it took their test vehicle to stop in wet conditions. AA is best, C is worst.
Temperature A stands for how well the tire resists temperatures. A is best, C is worst.
Treadwear 300 based on their tests, a treadwear rating is given to the tire. In this case 300 would be okay. 400+ is excellent, 350-400 I'd probably consider good, 300-350 is okay, 250-300 is pretty poor, and below 250 is bad. Of course, those are just MY little brackets. The DOT just rates actual treadwear, it doesn't specify classes.