Common Speed Ratings for U.S. Passenger Tires

[Q45tech]

TABLE 2-1 Common Speed Ratings for U.S. Passenger TiresPercentage of Percentage ofSpeed Total OE Tire Total ReplacementRating Speed Speed Shipments Tire ShipmentsSymbol (mph) (km/h) Example Applications in 2004 in 2004S, T 112–118 180–190 Family sedans and vans 83% 74%H, V 130–149 210–240 Sport sedans and coupes 15% 22%W, Y, Z >149 >240 High-performance sports cars 2% 4%RMA 2005Interesting that in 2004 on 15% of new cars/trucks had an H or V rated tire com oem standard and only 22% of replacement tires sold where either H or V

"The 2,371 rated passenger tire lines have the following distributionof tread wear grades according to information on NHTSA’s website:200 or lower, 11 percent;201 to 300, 21 percent; 301 to 400, 33 percent; 401 to 500, 22 percent; 501 to 600, 8 percent; above 600, 5 percent.

Tires graded A completed a 30-minute run at115 mph without failing; tires graded B completed a 30-minute run at100 mph, but not 115 mph; and tires graded C failed to complete a30-minute run at 100 mph. According to NHTSA website data, 27 percentof the 2,371 rated passenger tire lines have an A grade, 59 percent aB grade, and 11 percent a C grade.11

http://onlinepubs.trb.org/onlinepubs/sr/sr286.pdf

Scarey what everyone else on the road might be using.

[Victor]

You can't legally drive at 130 MPH, and most people would never even attempt it, so why waste your money on a high speed rated tire? Generally high speed tires are made with thinner walls and tread, so they wouldn't last as long either.

Your figures say 15% of new cars come with high speed tires, and 22 percent of replacements are high speed, so seems a lot of people are paying for a high speed rating they don't need. Methinks equiping a car with high speed rated tires is more an advertising ploy to justify a higher price for a sport or touring model car.

Get a couple of speeding tickets and watch your insurance go up $500 to $2000 a year above what a driver with no tickets would pay.

About the only place you could really use a high speed tire would be on the autobahn in Germany. I spent two years in Germany and often drove 120 to 140 MPH. It is really not enjoyable. Things come up on you too fast, require constant attention. I think 85 to 90 MPH is an enjoyable rate of high speed travel.

[maxnix]

You can't legally drive at 130 MPH, and most people would never even attempt it, so why waste your money on a high speed rated tire?

Let's put it theis way, why isn't any company's top rated tire not an S, T or even and H rated tire?

Quite simply, it is because they are the strongest construction with the most stable tread and carcass design.

Let's use your logic and say why do speedometers show speeds over 80 mph because it is illegal to drive faster? In the 80's, some GM products topped out at 85 mph then it was terra incognita as far as GM was concerned. I do not want to go back to that myopic vision of instrumentation.

Come the think of it, why do tachometers register past the red line or below idle? See the absurdity of that line of logic now?

[Q45tech]

Don't worry after the election, there will be 75 mph speed limiters on all new cars.

Please understand that the speed rating tests are done on BRAND NEW TIRES unfortunately as the tires age and the internal filaments fail the real rating declines with every mile.

All we do know is that Michelin warns that after 20,000 miles tires start to fail at an exponential rate regardless of whether they are S, T, H, or V-Y.

There is a reason that high performance tires wear fast so they won't get into the danger mileage area and expose manufacturers to liability.

I am more worried about the temperature rating and the number of B tires on the road.

What they don't tell you is even a H tire rated for 30 minutes brand new at 130 mph may fail at 100 mph near end of life and be dangerously overheated after 4 hours on the interstate at 90 mph in 95F trips to Florida.

The is a body of knowledge on H rated Police Tires and reasons they are replaced before wearing out by State Patrol Agencies.

http://www.nlectc.org/testing/tires.htm ... /index.htm

[98Q45tourist]

I just bought a set of Goodyear Assurance tires for my Q. They are T rated and have a treadwear of 700. I don't think I've ever seen such a high treadwear rating. They are very quiet and provide a pretty comfortable ride though. I'm not sure if I got duped. Does anybody know if they were a good choice?

[maxnix]

You were duped big time. Way too low a speed rating and therefore way too weak construction. Way too hard for TCS to work effectively.

RTFSM and OM.

I would take them back and consider a serious upgrade. I bet 60 - 0 in the dry is 150+ feet. I'd hate to think about the wet.

I'd say take them back and upgrade them to OEM specification. Anything below an H rating is verboten and only if you drive like your Grandma.

Does the load rating meet the 94 minimum OEM specification? If not, you have a actionable cause for negligence against that tire dealer.

[szh]

I just bought a set of Goodyear Assurance tires for my Q. They are T rated and have a treadwear of 700. I don't think I've ever seen such a high treadwear rating. They are very quiet and provide a pretty comfortable ride though. I'm not sure if I got duped. Does anybody know if they were a good choice?

Dangerous thing to do to a Q45. These are heavy cars and T-rated tires are simply not what you should have on them. Yes, you may not come close to those speeds on the car, but this rating is also a measure of the internal quality of the tire and its ability to handle loads, etc.

What is the load index listed on the side of the tire? If not at least 94 (for a 1997-2000 Q45) or 95 (for 1989-1996 and 2001-2006 Q45), then you have a serious problem - anything less is too low for the weight of the car.

The tire will never last for the tread life - internal belt and other failures will make them unsafe long before you come near the end of tread life. Plus, and this is equally important ... if you do not drive the tire enough to wear them out in 5 years (from the date of manufacture listed on the side of the tire), then longevity is irrelevant. Tire rubber hardens and cracks after some years - anything over 5 years should be discarded, regardless of the amount of tread left on it.

Z