Replacing 4.80x12 Tires on Harbor Freight Trailer with Tires that have Better Highway Rating

Question:

Hi, I have the harbor freight 1195lb trailer SKU 62648 that comes with factory 4.8 x 12 in. tires. I would like to upgrade the tires and wheels to part # AM3S120 for better highway rating but need to confirm the tire sidewall will have enough backspacing clearance. Using a tape measure it looks like there is about 3 inches of backspacing on the existing tire which leaves about a 1 inch space between the sidewall and trailer. Thanks

asked by: Tim A

Expert Reply:

The Kenda Loadstar ST175/80D13 Bias Trailer Tire # AM3S120 that you referenced is going to close that trailer frame to tire gap by almost a full inch. This would put the new tire much too close to the frame on your Harbor Freight Trailer.

The issue is that the existing 1 inch clearance between your trailer and tire side wall is already as close as I recommend having. Any wider of a tire and you are risking contact with the trailer frame because you still have to allow for some flex on the tires during travel and with added weight to the trailer.

The best recommendation I can give as far as replacing the tires on your trailer with ones that are better equipped for highway driving is to use radial ply tires that are the same size (if your existing tires are bias ply). Radial tires feature cords that run at a 90 degree angle to the direction of travel (as opposed to the cords on a bias ply tire that run at a 32 degree angle) which essentially allows it to flex more for better ground contact, stability, and tread wear. Because of this construction it will also run cooler than a bias alternative, making it better suited for higher speeds.

For this I highly recommend the Taskmaster 4.80R12 Radial Trailer Tire # TT48012C. This tire features a maximum load of 990 pounds at 90 psi and an excellent speed rating of 81 mph. I have included a short video review that you can check out as well.

expert reply by: Chris R