Best ST175/80-13 Trailer Tire Option for Tandem Axle Pontoon Boat Trailer  

Question:

Expert Reply:

Special trailer tires, the ST-type, are constructed differently than passenger vehicle tires, which are designated with the P prefix. Trailer tires are made with stiffer side walls to better handle vertical loads and higher air pressures whereas passenger vehicle tires are made to allow for better grip and cornering. We do not recommend using any tire type for other than its intended application. For your boat trailer use only ST-type special trailer tires.

Within the trailer tire category there are both radial and bias ply types available. Radial trailer tires use a different ply construction that gives them more flexibility for better ground contact. They also tend to run cooler than bias ply tires. Bias ply trailer tires have stiffer sidewalls that make them better for off-road and agricultural use. For a boat trailer driven mostly on highways and other paved surfaces a radial is the better choice.

Trailer tires also come in various weight load ranges as well as with varying speed ratings. It is important to choose a tire that has the appropriate weight capacity and speed rating for your driving needs. The reason most trailer tires fail is heat. Excessive heat comes from three main causes: incorrect inflation pressure (too high OR too low); exceeding the tire weight rating; and driving faster than the tire's rated speed. Avoiding all of these issues will typically lead to a longer lifespan from your tires.

Switching to a larger tire can sometimes be beneficial if it means a higher-weight-rated tire can now be used but it can also lead to concerns with clearance at either the side of the trailer frame or within the wheel wells. Switching from a 175mm width tire to a 195mm width means less clearance between the tire inner side wall and the trailer frame. Switching from a 13-inch to a larger 15-inch diameter tire potentially means clearance issues within the fenders or wheel wells. The bottom line is that a larger size of special trailer tire in and of itself does not necessarily gain you anything.

In your current 175/80-13 tire size we have both tires alone and tires pre-mounted with wheels; all item in your size are shown on the linked page. For a 4400-lb-rated tandem trailer each tire/wheel has to be able to handle at least 1100-lbs. Using a tire rated for more weight than you need it to carry means cooler operation.

For instance, Kenda Load Range D 175/80-13 tire # AM10210 can handle up to 1610-lbs at its rated 65-psi pressure. Also this tire can handle highway driving speeds up to 81-mph. This tire will give you plenty of capacity and safety margin without causing any clearance problems.

expert reply by: Adam R

0