When I bought tires for my trailer the guy told me the difference between trailer tires and passenger car tires is weight rating. Yea 6 plies and will hold 2000lbs a tire is great, but not needed on a 18' boat. Whats your boat and trailer weigh? If car tires will get the job done dont worry. If your that worried about and do as the books say, you should change your trailer tires every three years. In which case you will want the less expensive car tires. :idea:
Wow, and my car tires under Lowrider are only rated at 1900+ pounds each.
Well hotrod, I hope that plan works for you, but it has one major problem.
Reducing tire pressure INCREASES tire sidewall flex, which increases the temperature of the rubber tire body. Tires are basically melted into one single solid object, and when they near the temperature at which they were melted together, they melt back apart, usually throwing the tread off.
Buy one of the fairly inexpensive IR thermometers that will read up to about 300* and stop every so often. See what the tires are heating up to. The vulcanizing temp is low, only arround 270*F.
I tow regularly here on the highway in temps as high as 105 in normal July's and Augusts (being cool so far this year), and NOT slowing down to 55mph either. My car radials have never given trouble, even at 5+ hours of continuous highway speeds in the mid-day sun. I do not buy the cheapest ones available tho. Buy a temperature grade of at least "B", "A" would be best. That is the indicator of how well the tire fights heat build-up.
I AM only towing arround 2500 pounds max, on a single axle trailer, and have been for almost 30 years.