ST175/80D13 Trailer Tires Set of 4 - Heavy Duty Bias D

In this review of the ST175/80D13 trailer tires set, the bottom line is simple: this set is best for owners of small to medium trailers who need affordable, heavy duty bias tires built for load capacity and longer tread life. These are a set of four new ST175/80D13 bias tires with an 8 PR load range D rating and a deeper tread pattern intended to extend service life. The reviewer found them to be a sensible choice when maximum single-tire load capacity and rugged trailer-only construction matter more than premium highway comfort.

Key Features

• Set of 4 new tires: Buying a matched set ensures consistent wear and load handling across all trailer wheels for predictable towing behavior.
• 8 PR, Load Range D: The 8 ply rating and D load range provide a high maximum load of 1,570 lbs at 65 psi, suitable for many utility and travel trailers.
• Deeper tread design: The deeper tread offers extended tread life and improved durability under trailer loads compared with shallow-tread alternatives.
• Trailer-specific bias construction: Built specifically for trailer use, the bias construction prioritizes load carrying and trailer stability over passenger-vehicle ride comfort.
• One year limited warranty: A distributor-backed limited warranty gives buyers protection against early defects for the first year of service.

Who It's For

The ST175/80D13 set is ideal for owners of small utility trailers, boat trailers, and campers that specify 175/80D13 tires and require a robust load rating. It suits fleet customers or individuals who prefer buying a matched set and need the higher 1,570 lb single-tire capacity that a Load Range D tire provides.

Those who want a softer ride or tires rated for sustained highway passenger use should look elsewhere, since these are trailer-only tires with bias construction and are optimized for load bearing rather than low-noise cruising. If exact width fitting is critical, verify rim and fender clearances, as some customers note the tires can run narrower than expected.

Pros & Cons

Pros

• Durable construction with an 8 PR rating that supports heavy trailer loads reliably.
• Deeper tread for longer service life compared with basic trailer tires.
• Good value for a matched set of four new, first-quality tires with a warranty.
• Designed specifically for trailer use, reducing the risk of premature wear from inappropriate vehicle use.

Cons

• Some buyers report mixed fit and size feel, with a few saying the tires run narrower than expected.
• There are isolated reports of tires arriving with very low tread; inspect tires on receipt and use the warranty if needed.

Specifications

Tire Size	ST175/80D13
Brand	Free Country
Ply / Load Rating	8 PR, Load Range D
Overall Diameter	24 in
Section Width	6.8 in
Tread Depth	0.29 in
Max Load (single)	1,570 lbs @ 65 psi

Our Verdict

The ST175/80D13 trailer tire set is a practical, value-oriented choice for trailer owners who need a strong load capacity and longer tread life from a trailer-only bias tire. For those replacing all four tires or outfitting trailers in fleet quantities, the matched set, deeper tread, and one year limited warranty make it a straightforward, cost-effective option.

Frequently Asked Questions

Are rims included?
No. These tires are sold as new tires only; rims are not included.

Can these be used on passenger cars?
No. They are designed for trailer use only and are not intended for passenger-vehicle applications.

What is the maximum load per tire?
Each tire is rated to carry up to 1,570 lbs at 65 psi.