ST225/75R15 Travel Trailer Tires: Which Load Range, And Which Tire

225/75R15 is the bigger of the two sizes that dominate the travel trailer shelf. Where ST205/75R15 is what sits under most single and light tandem axles, 225/75R15 turns up on heavier tandems, on toy haulers and on trailers that were specified with some margin. The practical consequence is that load range matters more here than it does one size down, because this size is sold in three of them and they are separated by nearly 900 lb per tire.

Load range: a letter that encodes how much the tire carries at its maximum cold inflation pressure. In this size: D is the 8-ply rating, E is the 10-ply rating and G is the 14-ply rating. No modern tire contains that many plies — the numbers are a legacy equivalence from when tires were built from stacked cotton layers.

What each load range carries in this size

Read the last column as a tandem-axle total and the decision gets concrete. Four load range D tires give you roughly 10,140 lb of tire capacity. Four load range E tires give you about 11,332 lb. Four load range G tires give you about 13,668 lb. Your trailer’s gross vehicle weight rating has to sit under whichever of those applies, with margin left over — and the margin is what makes a hot afternoon on an interstate uneventful.

Note what the speed symbols do as you climb. The load range G tire carries the most and is rated the slowest, at 75 mph. That is not a defect; it is the normal trade in an all-steel ST casing. If you routinely run at 70 mph on a hot day, the margin between your speed and the tire’s rating is thinner on a G than on an N-rated E.

Which load range is actually yours

This is not a preference question. Your trailer carries a certification label — usually on the forward roadside wall — that states the tire size, the load range and the cold inflation pressure the trailer was engineered around. That label is the specification, and it is the document that matters if an insurer ever asks.

Going down a load range is never acceptable. If the label says E, a D tire at the same size does not carry what the trailer was built to carry, regardless of how lightly you load it.

Going up has a condition, and people miss it. The extra capacity of a higher load range only exists at that tire’s higher maximum inflation pressure. A load range E tire run at load range D pressure carries load range D weight. So before you upgrade, read what is stamped on your wheels: rims in this size are commonly rated 65 or 80 psi, and fitting an 80 psi tire to a 65 psi wheel means you cannot legally or safely inflate to the pressure the upgrade depends on. The wheel becomes the weak part.

Can you fit 225/75R15 instead of 205/75R15?

People ask this constantly, usually because the 225 is cheaper per unit of capacity or because a shop has them in stock. The honest answer is that it is a bigger change than it looks, and it is governed by the label rather than by whether the tire physically goes on.

A 225/75R15 is wider and taller than a 205/75R15. Wider means you need clearance between the tires on a tandem axle and clearance to the fender and frame rail — travel trailer wheel wells are not generous, and tandem spacing is fixed. Taller means the trailer sits slightly higher, the speedometer-equivalent wheel rotation changes, and your coupler height changes, which affects how the weight distribution hitch was set up.

It also does not raise anything that matters. Your axle rating and the trailer’s GVWR are set by the manufacturer and limited by the axles, frame, brakes and suspension. Fitting a larger, higher-capacity tire adds durability margin above the load you already carry; it does not give you permission to carry more.

So: fit 225/75R15 when the certification label calls for it. If the label says 205 and you want more capacity, the correct move is a higher load range in the size you have — not a bigger tire the trailer was not specified for.

The one case where the swap genuinely comes up is a trailer that was built in both configurations and whose label reads 225 while the previous owner fitted 205s to save money. That is the reverse problem and it is worth catching: tires one size and one load range below the label have been carrying more than they were rated for, probably for years, and the correct response is to go back to what the label specifies rather than to keep the cheaper set going for one more season.

What to look for, beyond the size

The DOT date code, before anything else. Four digits on the sidewall give the week and year of manufacture. Trailer tires fail from age and heat rather than from wearing out, so a tire that has sat in a warehouse for two years has already used part of its life before you fit it. Check the code on arrival and reject a set that is stale. How long trailer tires last covers the timeline.

The speed symbol, not just the load index. M is 81 mph, N is 87 mph, L is 75 mph. These are not aspirational numbers — they are the conditions the casing was validated under, and heat is what destroys ST tires.

Whether it is sold singly or as a set. Trailer tires should be replaced as a set, because they aged together. A set of four arriving with one date code is operationally simpler than four separate orders that may not match.

ST service, not LT or passenger. Every tire on this page is an ST — special trailer — tire, with the stiffer sidewall that resists the lateral loads a trailer axle generates. ST vs LT covers the switch honestly, including when it is defensible.

Availability if one fails. A budget brand at half the price is a reasonable buy right up until a blowout 200 miles from anywhere. Goodyear and Carlisle have networks; the budget brands on this page mostly do not.

The picks

Goodyear Endurance, load range E, 117N. The premium answer and the one most often named by owners replacing a set that failed. You are paying for a major manufacturer’s build, a published warranty, a dealer network and an N speed symbol. It is sold individually, so a full set is four purchases and a real amount of money.

Carlisle Radial Trail HD, load range D, 113M. The only load range D tire here, and the right tire if your label says D. Its listing states a 65 psi maximum, which is the pressure a D-rated trailer and its wheels were built around. The M speed symbol caps it at 81 mph, which is the honest cost of the saving.

Transeagle ST Radial II, load range E, 117/112N. The same load index and speed symbol as the Goodyear at a fraction of the price. The dual load index means it is rated for dual-wheel fitment as well. The trade is a much shorter track record and no meaningful service network — which is exactly why date-code discipline matters most on a tire like this.

Free Country Grand Ride, load range E, set of four. Sold as a complete set with a curb scuff guard, which matches how trailer tires get replaced: all at once, with one date code. The downside of a set is the mirror of its advantage — you cannot buy a single matching replacement from the same batch later.

Transeagle ST Radial all steel, load range G, 123/119L. Far more tire than a typical travel trailer needs, and exactly right for the trailer that keeps shredding D-rated tires. An all-steel casing resists the heat damage that kills lighter ST tires. Check your wheels’ pressure rating before you even consider it, and accept the 75 mph speed symbol and the harder ride.

The three things that outlast the brand choice

Whichever of these you fit, three habits determine whether you get the full life out of them, and all three matter more than which name is on the sidewall.

Cold pressure, set to the sidewall. Not a car number, not warm, not eyeballed. A trailer tire run underinflated builds heat in the sidewall and fails there, and nothing about buying a premium brand protects you from that.

A monitor, because you get no warning otherwise. A trailer tire going down gives the driver nothing to feel until it comes apart. A TPMS is how you find a slow leak while it is still a slow leak, and the TPMS versus gauge comparison explains why you want both rather than either.

Covers, and a replacement date in the calendar. UV is the dominant failure mechanism on a parked trailer, so covers are the cheapest life extension available. They slow aging; they do not reset it. When the date code says the set is done, the set is done regardless of how much tread is left — and if yours are wearing unevenly before that, inside-edge wear is an axle problem rather than a tire problem.

How we picked

We have not run these tires to failure and we do not own a trailer to run them on. The load indexes, speed symbols, load ranges and inflation figures above are each manufacturer’s published specifications or the figures stated on the live retailer listing, read in October 2026; the per-tire weights are the standard values for those load indexes rather than numbers we derived. Every listing on this page was confirmed live and in stock before it was featured. Current prices come from retailer listing data read automatically and date-stamped — we never type a price by hand. Load and inflation guidance generally follows NHTSA tire safety information and the marking requirements of FMVSS 109. The rubric and its weights are on how we pick. Always read the sidewall on the tire you are buying and the certification label on your own trailer — those two documents govern, not this page.