What Do the "D" and "C" Mean for Trailer Tires ST175/80D13C?

Updated 05/15/2019 | Published 05/14/2019

Products Featured in This Question

Kenda ST175/80D13 Bias Trailer Tire - Load Range C

(3945)

$79.67

Provider ST175/80R13 Radial Trailer Tire - Load Range C

(1113)

$101.48

Question:

I have a ST175/80D 13C trailer tire. What do the D and C mean?

asked by: Scott A

Expert Reply:

For your ST175/80D13C tires, the D means that they are diagonal internal construction more commonly referred to as bias ply tires. The cords run at a 32 degree angle versus radial tires which run at 90 degrees. The C in that location used to signify the standard bead seat, but if there is a space between the size and that C then it most likely refers to the load range rating on your tires.

If you are looking to replace those tires, I recommend using radial tires for highway driving because they ride smoother, don't heat up as much, and will have a longer life. My recommendation is the Provider ST175/80R13 Radial Trailer Tire - Load Range C # TTWTRTM1758013C which are rated for 1,360 lbs at 50 psi and max speed of 81 mph. They have automotive grade tread for better traction as well.

If you will be trailering off-road, then I recommend the bias tires which are slightly stiffer construction with less flex. I recommend the Kenda ST175/80D13 Bias Trailer Tire - Load Range C # AM1ST51 which are rated for that same 1,360 lbs at 50 psi and max speed of 81 mph.

expert reply by: Jason S