therock

iTrader: (2)

Ok, I'll get hammered but I still want to know.

I have 3:42 gears and my best fun is up on the slab stretching it out between me and a challenger. In light traffic.

My tires are Michelin LT 265/70/R17 S rated for 112 MPH. This is always on my mind so I only do very short runs above said.

With good tread and pressures and no load is there more head room? Do they test with more load than a empty truck would put on them?

I had H rated 130mph Cross Terrains but they went away in 30k.

Mangled03gmc

iTrader: (95)

I am sure that they are under rated for just them reasons. I have seen all terrain tires go 120 or better.. Not that it is the smartest thing to do..

PathfinderJr

iTrader: (6)

The speed rating on a tire is the max safest sustained speed that the tire can handle in a minutes time. Meaning an S rated tire can safely sustain a max of 112mph for a minute before things *might* start to fail. That is not to say that the tire is gonna fail after you took it to 120mph for 15 seconds, so it's kind of a goofy rating.

Now all that being said, don't anyone be a dumbass and try to prove/disprove the ratings, get yourself hurt, and come back complaining.

Mr. Sandog

I wouldn't do it. The numbers are there for a reason.

therock

iTrader: (2)

I hear you folks.

I confess I have been to 125 for less than a minute several times. I installed a 140 mph speed-o just so I can see where I'm at. I read the ratings are for the centrifugal force the tire can handle. Some say it's side wall load. So I am still confused. I do know there is a rating so I get the butterfly's for sure.

No one really mentioned it much and I never even considered it until the Ford Explorers under inflated OE tires started killing people.

I'm 55 years old and have had several muscle cars back in the day with some really lousy speed rating wise tires and have ran them well above the ratings for longer stints than I do now in pure uneducated ignorance. I'm talking non radials and such.

So I know we can get away with some, I am just looking for more hard data on the conditions they are most likely to blow. I know there is a test where they push the tire against a drum to simulate a load at a given speed. I am just wondering about the amount of weight applied vs what my vehicle applies unloaded.

I don't get on interstate much and I usually just jostle to a less congested spot ( the front of a pack) and settle down to the flow. Then a hot-dog will appear and with open road ahead we go at it for a bit or until we come up on another pack. Short and sweet. It's just those darned butterflies.

terravast4

iTrader: (25)

When I was younger I had the tread let go on my nova at about 130. Back then I thought a tire was a tire and had no clue about speed ratings. it beat the whole side of the car to hell and I was lucky not to wreck. it is not worth it. if you plan on going fast get some good tires and keep them properly inflated.

Mr. Sandog

It's simple, really. Buy tires rated at the speed you want to run. If you don't want to buy new tires, stay under 112 MPG.

If you don't, and a tire lets go, not only might you kill yourself (which would suck for you), but you could also hurt someone else, an innocent 3rd party.

Pay if you want to play.

budhayes3

iTrader: (19)

When TTP ran my truck on the dyno, they took it up very high, seemed like 150 to me (I'm sure it wasn't going that fast, but my heart was beating that fast as they were beating on my truck), Anyway, I was running 285/75-16's BFG AT's (33's) at the time, and the sidewalls looked like a top fuel dragster when it does it's burn out...I thought they were going to blow. Surprised I didn't lose my driveshaft. I'm sure that they well exceeded the speed rating on those tires, but the truck was fine and the tires are now on my buddy's 03 HD and probably have about 40k on them and still going. So those tires lived through it, but I don't think that it was a wise thing to do. In the future I'm going to stick to my tire's speed ratings, just to be safe.

viciousknid

iTrader: (8)

You'd want to Google the specific information but it is based on Sustained speeds. Pretty sure it's more than a minute tho.

The tires on my blazer are rated for 85mph and thats as far as my speedometer goes. I've pegged the speedo and kept my rpms climbing for another 500-1000rpm before backing out without problems.

I'm not saying DO that. But you'd want to google the sustained time and see what it is.

therock

iTrader: (2)

Will do. Thats what I'm looking for. More details on the testing.