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Old 10-27-2021, 07:38 AM   #10
Bill
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Join Date: Feb 2003
Location: The mountains of Scottsdale, AZ, and the beaches of Maine
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Tire failures seem to be overwhelmingly due to under-pressure. At low pressure, the tire flexes more as it rolls, and flexing causes heat, which causes failure.

On your 2003 TM, you most likely have 14-inch tires, probably something like ST205-75R14. The "ST" prefix means "Special Trailer", and ST tires are "rated" at 65 mph. I've never seen a real explanation of what "rated" means, or why ST tires are rated at 65 mph, even from the tire experts. Bottom line, though, you probably shouldn't exceed 65 or so for long periods.

These tires are adequate, but don't have a lot of load-bearing margin. So you need to be conscious of weight as you pack. A lot of folks have changed to 15-inch tires to increase the margin. The central important point is to air up your 14-inch tires to 50 psi before you drive in the morning (this is referred to as "cold inflation" pressure), and then don't change it. Pressure will increase as you drive, and that is accounted for in the tire design. Do not let air out of the tires! This will result in under-pressure, and failure.

As long as you air up to 50 psi cold, and not more, over-pressure is not a problem.

Hope this helps

Bill
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