A Question about Tires for Big Daddy or anyone else

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#1
What is the speed rating on tires actually good for? I am asking Big Daddy because of his Law Enforcement back ground, but please ANYONE chime in. I just bought Winter Tires and rims and H rated tires (Good to 210 kmh, 127 mph) Now does this mean that if I travel faster than that, that the tires will blow on me? Or is that just a recommended speed? I hate this, now that I have winter tires..........EVERYONE wants to race with me and I get passed at 120mph because I am skeptical of the tires failing on me so I slow down. Could I feesably hit 150 mph for short distances just to save face and not be beaten by an Opel? OR must I remain at the H rating so I don't crash and die?
Thanks in advance
 

Big Daddy

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#2
Tool I think this write up by Yokohama says it the best:

Speed Rating
Speed ratings are certified maximum sustained speed designations assigned to passenger car radials and high performance tires. Because of the evolution of high-speed passenger car travel, it was necessary to establish a way to rate a tire's high-speed capability. In the U.S., these ratings are based on tire testing in laboratory conditions under simulated loads (European testing uses actual road testing). For a tire to be speed rated by the U.S. Government, it must meet certain minimum government standards for reaching and sustaining that specified speed. Domestically, high performance tires must be speed rated. The tire industry defines high performance tires as those with speed symbols of "S" or greater and aspect ratios of 70 or lower. Yokohama goes one step further and defines high performance tires with a speed symbol of "H, V, W, Y," or "Z" and an aspect ratio of 70 or less (typically, 60 or less). Conventional passenger car radials need only meet the minimum Department of Transportation standard of 85 mph. Speed symbols may currently be marked on a tire in any of three ways: 205/60ZR15; 205/60ZR15 89W; or 205/60R15 89W. The International Standard Organization system (ISO) currently serves as a worldwide standard for tire markings. At the end of a transition period, any speed symbol denoting a fixed maximum speed capability will be at the end of the service description following the tire marking (illustrated in the second and third examples above).



*z rating refers to open ended speed capability.

Warning:
Speed ratings apply only to the tire, not to the vehicle. Putting a speed rated tire on any car does not mean the car can be operated at the tire's rated speed.

Notice they sat "maximum sustained speed ", therefore you could reach higher speeds with no problems, but sustaining a higher speed is not recommended. Hope this helps.
 
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#3
tool fan, unfortunately the speed ratings are there for a reason. They tell you the top speed you can drive with those tires and you're not supposed to go over that speed. It is best that perhaps you turn your head the other way when somebody wants to race you past the 127mph. I'm all for high speed runs, but not when the tires aren't up to the task.
 
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#5
From what I have read, the speed rating is for "sustained" speeds, and the primary concern is heating of the tire and subsequent tread separation or blowout. I'm pretty sure that you are OK 10 - 25 mph over the rating for a few minutes, but definitely not for anything longer. See below.

How is the tire's speed capability achieved?
As the speed of a tire increases, it's components tend to grow or deform. This deformation leads to heat generation. This is a normal effect of the deformation of the tire's components due to centrifugal force. The faster the tire spins, the greater its tendency to deform. And the more it deforms, the more heat is generated.

But for tires driven at high speeds, controlling heat levels is critical. Engineers must find ways to control tire growth so that heat levels are confined to acceptable tolerances.

To overcome this problem, speed-rated tires are designed with advacned belt configurations engineered to resist and control deformation. This allows the tire to be driven at higher speeds without excessive heat buildup.

How does the speed rating relate to handling?
The fact that a tire is speed-rated indicates very little about its handling capabilities. The speed rating, as mentioned earlier, is almost entirely dependent on the tire's belt structure.

Think of the speed rating as being like a temperature grade. It tells nothing about the tire's construction, its handling or its wearability. It is merely a measure of the tire's integrity at high speeds.
 
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#7
tool fan, i know what you mean. people get more aggressive when i have my 16's w/ snows on.

it is so sunny where i live that snow melts off the roads super fast, but all the same i need my snows on for other things. but when i go skiing i rip up into the mountains and typically i go fast, my tires smell like shit, but this folks are all right, it is sustained speeds. there are no guarentee's, but realistically the speed rating doesn't mean "if you go 5mph over this they just explode, that will teach you to follow the rules"
 


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