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Old 12-02-2012, 12:33 AM   #21
B&T
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I always use max cold pressure on trailer tires and use a TPMS system to keep real-time tabs on tire pressure and temperature. I also always keep the speed at 65 or below when towing since there are no ST tires that are rated for speeds above 65.
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Old 12-02-2012, 06:38 AM   #22
JRTJH
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Quote:
Originally Posted by B&T View Post
I always use max cold pressure on trailer tires and use a TPMS system to keep real-time tabs on tire pressure and temperature. I also always keep the speed at 65 or below when towing since there are no ST tires that are rated for speeds above 65.
I don't want to sound like "conflicting data" with this statement and completely agree with you that under what Goodyear calls "normal service" the ST tire is rated at the stamped PSI and 65MPH. However, Goodyear, in a number of pieces of their factory literature states:

Based on industry standards, if tires with the ST designation are used at speeds between 66 and 75 mph, it is
necessary to increase the cold inflation pressures by 10 psi above the recommended pressure for the load.
o Do not exceed the maximum pressure for the wheel.
o If the maximum pressure for the wheel prohibits the increase of air pressure, then the maximum speed must be restricted to 65 mph.
o The cold inflation pressure must not exceed 10 psi beyond the inflation specified for the maximum load of the tire.


Other tire manufacturers also state the same "exemption" for their ST tires. Not all manufacturers have this "exemption" listed in their literature, but some do.

So, to respond only to your last comment about "NO ST TIRES THAT ARE RATED FOR SPEEDS ABOVE 65" There are some that the manufacturers have conditions for using above that speed.

REF: http://www.goodyear.com/truck/pdf/pr...Brochure_P.pdf

On the reference, go to the last page in the yellow box on the right hand side.
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Old 12-02-2012, 08:33 AM   #23
B&T
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Quote:
Originally Posted by JRTJH View Post
I don't want to sound like "conflicting data" with this statement and completely agree with you that under what Goodyear calls "normal service" the ST tire is rated at the stamped PSI and 65MPH. However, Goodyear, in a number of pieces of their factory literature states:

Based on industry standards, if tires with the ST designation are used at speeds between 66 and 75 mph, it is
necessary to increase the cold inflation pressures by 10 psi above the recommended pressure for the load.
o Do not exceed the maximum pressure for the wheel.
o If the maximum pressure for the wheel prohibits the increase of air pressure, then the maximum speed must be restricted to 65 mph.
o The cold inflation pressure must not exceed 10 psi beyond the inflation specified for the maximum load of the tire.


Other tire manufacturers also state the same "exemption" for their ST tires. Not all manufacturers have this "exemption" listed in their literature, but some do.

So, to respond only to your last comment about "NO ST TIRES THAT ARE RATED FOR SPEEDS ABOVE 65" There are some that the manufacturers have conditions for using above that speed.

REF: http://www.goodyear.com/truck/pdf/pr...Brochure_P.pdf

On the reference, go to the last page in the yellow box on the right hand side.
Yes, Ive seen that.

I found it strange that they used the word "wheel" instead of "rim" in that statement. One could possibly reason that a "wheel" is made up of a combination of the tire and rim and should be rated according to it's lowest rated component.

In the last line:

"The cold inflation pressure must not exceed 10 psi beyond the inflation specified for the maximum load of the tire."

Since I am running mine at "the inflation specified for the maximum load of the tire." -- i can not add 10psi. Very ambiguous statement!

So, in my mind, 65 is still the max speed that my ST tires should be trusted at.
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Old 12-02-2012, 10:57 AM   #24
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B&T,

I agree with you, I usually run about 60 or so and keep my tires at the max rated PSI on the sidewall. I'm just not one to push the envelope by adding a few pounds of air and speeding up. I am just fine tooling along watching the scenery and not feeling like I'm forced to push the limits to get there a couple minutes sooner. I haven't found anything (other than grand kids) that would justify wanting those few extra minutes, and after being with them for a day or so, I am sure you know the outcome of "wanting to get there faster"

As for that ambiguious statement about exceeding the maximum pressure. You might be interpreting it "ambiguiously"

What it says is that the pressure must not exceed the maximum recommended load PSI rating (plus 10PSI) so, if you're using 13, 14 or 15" load C tires, the max load PSI is 50 so you couldn't exceed 60PSI. however, if you're using 15" load E tires or 16" load E tires, the max load PSI is 65PSI so you couldn't exceed 75PSI. Those maximum increases are based on whether the "wheel" or the "rim" is rated at the increased PSI.
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Old 01-31-2013, 07:42 AM   #25
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Where do you find the max pressure for the wheel. I have the cast aluminum wheels on my 29res and have been thinking of going to the E rated tires because they are rated at 80psi and I wouldn't have to worry about running them at 75psi being I am fully loaded
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Old 01-31-2013, 03:33 PM   #26
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The maximum load and the maximum pressure should be stamped on the back side of the wheel (closest to the brake drums) if you don't see it there, then it's is INSIDE, on the rim.... If you can find any numbers on the back side of the wheel, most any tire shop can tell you the max pressure. Don't forget to change out the valve stems to the higher pressure as well !!!!!
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