Keep On Rolling
Here are seven trailer tire
tips that will help you get
the most use and longevity
out of your set of tires
- 1. ST
Tires designed for a boat trailer have “ST” on the sidewall. Despite what you hear, and what folks at the boat ramp say, passenger car and light truck tires should never be used. Trailer tires have a stronger sidewall to support the weight of the boat as the trailer is pulled around curves at high speed. Industry standards dictate that ST tires are restricted to a speed of 65 mph unless a different speed restriction is indicated on the tire sidewall. If speeds from 66 to 75 mph are used, the tire cold inflation pressure can be increased by 10 psi without any increase in load. - 2. PSI
Under-inflation of radial tires cannot be determined unless a tire-pressure gauge is used. A visual inspection is never good enough. Underinflation is also the cause of most passenger-car and boat-trailer tire failures. Tires lose about 2 PSI of air pressure every month. - 3. Tire Type
Radial boat trailer tires provide a longer running life and run cooler than bias ply so there’s less of a chance of a blowout. Bias ply are less expensive and ideal if your trips to the boat ramp are brief. - 4. Same
Never mix radial tires with bias ply tires. Use one type only. - 5. Load Rating
Every tire, be it for car, light truck, motorcycle or boat trailer, has a load rating, with the lightest being “A.” Most boat-trailer tires have load ratings of B, C, or D. For example, a small single-axle boat trailer may use tires with a B load rating that may have a load capacity of 590 pounds. Because there are two tires on the trailer, the total capacity of the tires being used is 1,180 pounds, so the boat, trailer engine, fuel, and equipment can’t weigh more than 1,180 pounds. For single-axle trailers, tires can handle 100 percent of their load rating. For dual-axle trailers, loads must be reduced by 12 percent. - 6. Depth
Check tread depth on your trailer tires by placing a Lincoln penny upside down in the tread. If you can see the top of Lincoln’s head, the tread wear is excessive and the tire needs to be replaced. - 7. Valve Stem
When inspecting your trailer tires, don’t stop at only checking the sidewalls for cracks and the treads for wear, also take a look at the tire valve stems. Gently flex the stem to the left and right to ensure air isn’t released. The look at the base of the stem all the way to where the threads begin for cracks.
