Radial or Bias Ply ST175/80-13 Trailer Tires for a Boat Trailer

Question:

Having separation problems on subject tandem axle boat trailer tires for my 21foot 3inch Chris Craft Sea Hawk boat. The trailer does not have load equalizers. I am very careful to run the tires inflated to 50 psi cold tire pressure and the tires are about three years old two separated within the first two years. Do you recommend going to load range D or would it be better to go to a bias ply on a boat trailer due to the immersion in water after the tires are heated up form traveling to the boat ramp. I live in Florida. I estimate the weight of the loaded boat, motor and trailer to be about 4,500 lbs

asked by: Craig P

Helpful Expert Reply:

An ST175/80-13 trailer tire load range C (the ones we carry) is going to have a 1,360 pound capacity at 50 psi, bias or radial. So 4 of them total on a tandem axle trailer is going to have a capacity of 5,440 pounds; more than enough for the 4,500 pound estimated weight of the trailer loaded and ready to tow.

Typically trailer tires fail because they are either ran at the wrong psi and get too hot or because they are overloaded. It is also possible you just got some bad tires. If you are running the tires at 50 psi and the tires you have are rated high enough for the load then signs point to a bad batch of tires.

Going to a higher load range will not increase the capacity of the trailer but you could certainly use them. Radial tires actually run cooler than bias ply tires so going with radials will be just fine. For a load range D radial in the same size you can use # AM10210 that you referenced. If you want to go with a bias tire then use # AM1ST77.

If you notice uneven tire wear on the insides of the tread that is an indication that the trailer is most likely overloaded or there is something wrong with some suspension components and you will want to have a shop that works on trailers check it out. I have included a link to our FAQ article on trailer tires for you.

expert reply by: Michael H