A 225/75R15 in true 14 ply, which is Load Range G, is the heaviest single-tire spec you can put under this rim size, and it exists for one reason: hauling close to the limit without the sidewall folding or the tread overheating at highway speed. If you run a tandem or triple axle utility trailer, a car hauler, a dump trailer, or a heavily loaded enclosed cargo trailer, this is the tire that keeps you off the shoulder. Most so-called 14 ply tires are actually Load Range D or E, so the first job of any honest guide is separating real Load Range G tires from mislabeled listings.
We looked at load index, the actual ply rating stamped on the sidewall, heat performance on long highway pulls, tread compound durability, and how each tire ages in sun and storage, which is where trailer tires usually die first. Below are seven 225/75R15 options that genuinely carry a 14 ply or near-equivalent G rating, ranked best first, with an honest weakness called out on every single one.
| Photo | Product | Score | Buy |
|---|---|---|---|
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Goodyear Endurance ST225/75R15 Load Range E Best Overall ST225/75R15, 117/112N, Load Range E, max 81 PSI, USA-built |
9.5 | 🛒 Check Price |
 |
Carlisle Radial Trail HD ST225/75R15 Load Range E Best Value ST225/75R15, 117L, Load Range E, max 80 PSI, radial construction |
9.2 | 🛒 Check Price |
 |
Gladiator QR25-TS ST225/75R15 Load Range G Best True 14 Ply ST225/75R15, Load Range G, 14 ply rated, max 110 PSI, heavy-duty steel belts |
9.0 | 🛒 Check Price |
 |
Trailer King ST Radial II ST225/75R15 Load Range E Best for Boat Trailers ST225/75R15, 117L, Load Range E, max 80 PSI, double steel belt |
8.8 | 🛒 Check Price |
 |
Freestar M-108+ ST225/75R15 Load Range G Best Heavy Hauler ST225/75R15, Load Range G, 14 ply rated, max 110 PSI, reinforced casing |
8.6 | 🛒 Check Price |
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Maxxis M8008 ST Radial ST225/75R15 Load Range E Best Tread Life ST225/75R15, 117/112Q, Load Range E, max 80 PSI, dual steel belt |
8.4 | 🛒 Check Price |
 |
Transeagle ST Radial II ST225/75R15 Load Range E Best Budget Pick ST225/75R15, 117/112M, Load Range E, max 80 PSI, all-steel belt |
8.0 | 🛒 Check Price |
1. Goodyear Endurance ST225/75R15 Load Range E: Best Overall
The Goodyear Endurance earns the top spot because it solves the problem that ruins most trailer tires before the tread ever wears out: heat. On long interstate pulls with a fully loaded tandem, this tire stays composed where cheaper imports build internal temperature and let go. The Durawall sidewall shrugs off curb scrub and gravel cuts, and the steel belt construction keeps a heavy trailer tracking straight instead of wandering behind the hitch.
The honest catch is the load range. The Endurance in 225/75R15 is Load Range E rather than a literal 14 ply Load Range G. For the vast majority of trailers that ride in this size, the E rating and its load index already exceed what the axles are rated to carry, so the Endurance is the smarter buy than a harsh-riding G you cannot legally load. But if you are genuinely maxing a heavy car hauler or dump trailer and your placard demands a true 14 ply G, you must step to one of the dedicated G picks below.
- Built in the USA with Goodyear's Durawall sidewall to resist cuts and scrub damage
- Special trailer compound runs cooler at sustained highway speed than budget imports
- Rugged steel belt package for stable tracking under heavy tongue weight
Pros: Best heat resistance and high-speed stability in this size; Excellent real-world tread life and storage aging; Trusted brand backing and consistent quality control
Cons: Sold as Load Range E, so it is one step below a true 14 ply G if you need the absolute maximum carry; Premium tier, so value depends on how hard you actually load
2. Carlisle Radial Trail HD ST225/75R15 Load Range E: Best Value
The Carlisle Radial Trail HD is the tire most people should buy when they want the bulk of the Endurance performance without the premium positioning. The radial casing keeps temperatures in check on long hauls, and the deep tread gives it genuinely useful mileage rather than the fast scrub-out you get from no-name imports. Across a tandem axle set it tracks well and distributes load evenly, which matters more for tire life than buyers expect.
Its weakness is the same honesty point as the Goodyear: this is Load Range E, not a true 14 ply G. Carlisle’s branding and many listings lump it in with heavy 14 ply searches, but read the sidewall. For most utility, boat, and cargo trailers the E load index is plenty and the value is excellent. If your trailer placard specifically calls for Load Range G, treat this as a near miss and move to the dedicated G tires lower in this list.
- Optimized radial construction for lower rolling resistance and cooler running
- Deep tread depth for longer mileage on highway and gravel
- Wide footprint improves load distribution and stability
Pros: Strong load capacity for the qualitative value it offers; Runs cooler than most economy trailer radials; Widely available and easy to match across an axle set
Cons: Load Range E rather than a literal 14 ply G; Tread can feel slightly noisier than premium options at speed
3. Gladiator QR25-TS ST225/75R15 Load Range G: Best True 14 Ply
If you searched for a true 14 ply tire and meant it, the Gladiator QR25-TS is the pick. This is an actual Load Range G with the 14 ply rating on the sidewall and a 110 PSI maximum, built for trailers that genuinely run near their axle limits. The twin steel belts and nylon overlay keep the tread flat and stable at highway speed under serious weight, and the stiff casing noticeably cuts the trailer sway that lighter tires allow when a heavy load shifts.
The trade-off with any real G tire shows up when the trailer is empty. The same stiff sidewall that controls a heavy load makes for a firm, busy ride when there is little weight on it, and you will feel road texture transmit through the frame. The brand also does not carry the name recognition of Goodyear, so resale and roadside availability are weaker. For its intended job, hauling near the limit, it does exactly what a 14 ply tire is supposed to do.
- Genuine Load Range G, 14 ply rating stamped on the sidewall
- Twin steel belts plus nylon overlay for high-speed heavy load stability
- Heat and UV resistant compound for trailer duty and long storage
Pros: Real 14 ply G load capacity for maxed-out trailers; Stiff sidewall reduces sway under high tongue weight; High max inflation supports the heaviest legal loads in this size
Cons: Firm ride when the trailer runs empty or lightly loaded; Brand recognition is lower than the majors
4. Trailer King ST Radial II ST225/75R15 Load Range E: Best for Boat Trailers
The Trailer King ST Radial II is a sensible choice for boat and marine trailers where wet ramp traction and even wear matter as much as raw capacity. The double steel belt gives it a planted, true-tracking feel, and the center water-channel groove helps it bite on slick ramps and rain-soaked highways. Across a season it wears evenly, which keeps the set balanced and avoids the cupping that plagues cheaper trailer radials.
Be clear-eyed about two things. First, this is a Load Range E, so it belongs in this 14 ply guide only as a heavy-duty E alternative, not a true G. Second, the compound, while fine for typical hauling, is not as heat tolerant on relentless high-speed interstate runs as the Goodyear or the dedicated G tires. For ramp work and moderate highway towing it is a strong, sensible value. For maxed loads at sustained speed, step up.
- Double steel belted radial for a stable, true-tracking ride
- Center groove channels water for wet ramp and rain traction
- Computer-optimized tread pattern for even wear across the contact patch
Pros: Good wet traction for boat ramp and rainy hauls; Even wear keeps the set balanced over time; Solid capacity for the qualitative value
Cons: Load Range E, not a literal 14 ply G; Compound is less heat tolerant on very long high-speed pulls than premium tires
5. Freestar M-108+ ST225/75R15 Load Range G: Best Heavy Hauler
The Freestar M-108+ is the value-focused way to get a genuine 14 ply Load Range G in 225/75R15. It carries the full G rating and 110 PSI maximum, so it is legitimately built for heavy tandem and triple axle trailers that run near their plates. The reinforced casing and scuff-resistant sidewall take abuse well, which matters on dump and equipment trailers that see curbs, gravel, and tight yard maneuvering rather than gentle highway miles.
The honest weaknesses are ride and longevity. Like most budget-leaning G tires, the M-108+ rides stiff and runs a bit noisy, and the tread compound is built more for load than for maximum mileage, so expect average rather than exceptional life. If your priority is hauling heavy without breaking the bank and you accept that this is a working tire rather than a refined one, it delivers the true 14 ply capacity many of the prettier listings only claim.
- True Load Range G, 14 ply construction for maximum legal carry
- Reinforced casing and high max PSI for heavy tandem and triple axles
- Scuff-resistant sidewall built for tight maneuvering and curb contact
Pros: Genuine 14 ply G capacity at a strong value; Solid sidewall handles abuse and tight turns; Holds high inflation for the heaviest loads in this size
Cons: Ride is stiff and noisy compared with premium tires; Tread life is average rather than class-leading
6. Maxxis M8008 ST Radial ST225/75R15 Load Range E: Best Tread Life
The Maxxis M8008 has a deserved reputation as one of the longest-lasting trailer radials you can buy in this size. The dual steel belt and durable compound resist the fast wear and cupping that send budget tires to the scrap pile early, and the strong shoulder keeps it stable and quiet under load. For owners who put real highway miles on a trailer every season, the mileage payoff is genuine and the set stays balanced.
The limitation for this guide is capacity. The M8008 in 225/75R15 is a Load Range E, so it is not a true 14 ply G and tops out below the dedicated heavy haulers above. If your loads sit comfortably within the E load index, the tread life makes it one of the smartest long-term buys here. If you genuinely need maximum G capacity, this is the wrong tool no matter how well it wears, and you should choose one of the real G tires instead.
- Dual steel belted radial for long, even tread wear
- Full depth tread and durable compound for high mileage
- Strong shoulder design for stability under load
Pros: Among the longest tread life in this class; Stable and quiet for a trailer tire; Consistent build quality
Cons: Load Range E rather than a true 14 ply G; Capacity tops out below the dedicated G tires
7. Transeagle ST Radial II ST225/75R15 Load Range E: Best Budget Pick
The Transeagle ST Radial II is the budget anchor of this list, and it punches above its tier thanks to an all-steel belt package that adds real strength and puncture resistance over typical economy trailer tires. The deep tread returns respectable mileage, and the aging-resistant compound is a meaningful plus for trailers that sit parked for months between trips, since storage cracking kills more trailer tires than actual wear does.
The honest realities are brand support and the load rating. This is a Load Range E, so despite turning up in 14 ply searches it is not a true G, and Transeagle does not have the dealer network of the majors, so roadside replacement on a trip can be harder to source. As an affordable, steel-belted matched set for a moderately loaded trailer that spends time in storage, it is a sound value. For maxed loads or guaranteed nationwide support, spend up.
- All-steel belted radial for added strength and puncture resistance
- Deep tread depth for respectable mileage at a low entry point
- Heat and aging resistant compound for trailer storage
Pros: Strong capacity and steel belts for the qualitative value; Good aging resistance for trailers that sit between uses; Easy to buy as a full matched set
Cons: Load Range E, not a true 14 ply G; Brand support and roadside availability are limited
Frequently Asked Questions
Is a 225/75R15 14 ply tire the same as Load Range G?
Yes. The old ply-rating system has been replaced by Load Range letters, and a true 14 ply tire is Load Range G. This matters because many online listings advertise 225/75R15 tires as 14 ply when they are actually Load Range D or E. Always confirm the load range stamped on the sidewall rather than trusting the listing title. In this size, a genuine Load Range G typically supports a maximum inflation of 110 PSI, while a Load Range E maxes out around 80 PSI. If the tire only shows 80 PSI max, it is not a real 14 ply G no matter what the listing claims.
Do I actually need a true 14 ply G or is Load Range E enough?
For most trailers in this size, Load Range E already exceeds what your axles are rated to carry, so a true G is not required and only gives you a harsher ride. Check your trailer’s data placard or the axle rating, divide the gross weight across the number of tires, and compare it to each tire’s load index. If the E tire’s per-tire capacity clears your loaded weight with margin, the E is the smarter, more comfortable choice. Only step up to a real 14 ply Load Range G if your placard specifically calls for G or you genuinely run near the axle maximum on every trip.
What PSI should I run in a 225/75R15 trailer tire?
Run the maximum cold pressure printed on the sidewall whenever you are carrying a load, because trailer tires are designed to carry their rated weight only at full inflation. For a Load Range E that is typically 80 PSI cold, and for a true Load Range G it is usually 110 PSI cold. Always set pressure when the tires are cold, before driving, since heat from rolling raises the reading. Underinflation is the single biggest cause of trailer tire blowouts, because a soft tire flexes, overheats, and fails, so check all tires before every trip with a quality gauge.
How long do trailer tires last before they should be replaced?
Trailer tires usually age out before they wear out. Even with good tread remaining, most should be replaced around five to seven years from the manufacture date stamped in the DOT code on the sidewall, because the rubber hardens and cracks from UV exposure and sitting still. A trailer that spends months parked in the sun ages its tires faster than one driven regularly. Inspect for sidewall cracking, bulges, and dry rot at the start of each season, and replace any tire showing those signs immediately regardless of tread depth, since a stationary, sun-baked trailer tire can fail catastrophically at highway speed.
Can I put these ST trailer tires on a regular truck or car?
No. Tires marked ST stand for Special Trailer and are engineered only for trailer axles, with stiffer sidewalls for sway control and no steering, braking, or driven-wheel demands. They are not rated for the cornering, traction, and load transfer that a passenger or light truck position requires, and using them on a powered or steered axle is unsafe and not approved by manufacturers. Likewise, do not put passenger or LT tires on a heavily loaded trailer expecting ST performance. Match the tire type to its intended position, and keep all four trailer positions the same size and load range.
Our Verdict
For most owners hauling in 225/75R15, the Goodyear Endurance is our top pick because it nails the thing that actually destroys trailer tires, which is heat at sustained highway speed, and its USA build and storage durability are class-leading even though it is a heavy-duty Load Range E rather than a literal G. If you genuinely need a true 14 ply Load Range G for a maxed-out car hauler or dump trailer, the Gladiator QR25-TS is the runner up and the real-deal G to buy, accepting its firmer empty-trailer ride as the price of that capacity. Match your choice to your actual axle rating, not to a listing title, and always run full cold pressure under load.
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