An ST235/80R16 trailer tire is a radial “special trailer” tire that is about 9.25 inches wide, has an 80% sidewall, and fits a 16-inch wheel. It stands roughly 30.8 inches tall and comes in Load Range E through H, so each tire can carry about 3,400 to 4,500 pounds depending on the brand and load range.

Choosing one looks simple, but the details matter. Two tires with the same size code can differ by more than 1,000 pounds of capacity, and a tire under-rated for the axle runs hotter and ages faster.

This guide explains the size code, compares load ranges E, F, G and H, and reviews popular brands: Goodyear Endurance, Trailer King RST II, Mastertrack All Steel, RubberMaster RM86, Zeemax Fortress and Hi-Run. It also covers price, rim fitment, PSI and replacement timing. Specs come from manufacturer and retailer listings reviewed in 2026, so confirm the numbers on your own tire’s sidewall.

What Does ST235/80R16 Mean?

Every character in the code tells you something about fit and function. Here is how to read it:

• STSpecial Trailer
• 235Width in millimeters (about 9.25 in)
• 80Sidewall is 80% of the width
• RRadial construction
• 16Wheel diameter in inches

The math is easy to check. A 235 mm width times 0.80 gives a 188 mm sidewall, or about 7.4 inches. Add that above and below a 16-inch wheel and the overall diameter lands near 30.8 inches, which matches most published specs.

ST tires vs. LT and passenger tires

ST tires have stiff sidewalls built for the sideways forces a trailer creates in turns. Retailer listings consistently state that they are for trailer use only and should not go on passenger cars, SUVs or light trucks. The reverse matters too: keep trailer-specific tires on the trailer unless the manufacturer says otherwise. For the tow vehicle, see our picks for the best all-terrain tires and the best all-season tires for 2026.

How to read the full sidewall

A typical marking looks like ST235/80R16 124/120M E. The 124/120 is the load index (single tire / dual tires), the letter M is the speed rating, and E is the load range. Common speed ratings on this size are L (75 mph), M (81 mph) and N (87 mph). Our tire speed rating chart explains the full scale.

ST235/80R16 Trailer Tire Size and Specs at a Glance

ST235/80R16 Load Range E, F, G and H Compared

Load range tells you how much air pressure and weight the tire is built to handle. It is the single most important choice for this size.

Capacity differs by brand, so treat this table as a guide and read the sidewall. “Dual” applies only when two tires share one axle end. Most trailers with this size run one tire per side, so the single-tire rating is the one that counts.

ST235/80R16 trailer tire Load Range E (10-ply)

Load Range E suits many campers, cargo trailers and light equipment haulers. Keep in mind that “10-ply” is a strength rating, not a count of physical layers. Modern radials use steel belts and polyester cords instead. If you want a refresher on what ply ratings mean, our 10-ply truck tires guide covers it.

Load Range G and H (14 to 16 ply)

Load Range G and H tires are typically all-steel radials with more capacity and higher pressure. They make sense for heavy gooseneck, dump, hot-shot and car hauler trailers, or anywhere the axle rating leaves little margin.

Worked example: matching tires to your axle

Take a tandem-axle trailer with two 7,000 lb axles. Each axle has one tire per side, so each tire must carry at least 3,500 lb.

• A 3,520 lb Load Range E tire clears that by less than 1%.
• A 4,080 lb Load Range G tire gives about 16.6% headroom.

Which Trailers Use ST235/80R16 Tires?

This size is popular on mid-to-heavy trailers, including:

• Travel trailers, toy haulers and fifth wheels
• Enclosed cargo and car hauler trailers
• Equipment, utility and dump trailers
• Livestock and horse trailers
• Larger boat trailers

Popular ST235/80R16 Trailer Tire Brands Compared

The table below summarizes the models from popular searches. Specs come from manufacturer and retailer listings, so confirm the exact load index on the tire you buy. Explore more manufacturers on our tire brands page.

Goodyear Endurance ST235/80R16

The Goodyear Endurance is a Load Range E radial with an N speed rating and a 6-year limited warranty listed by its retailer. It fits owners who want a name-brand E tire for campers and cargo trailers. For background on the manufacturer, read our Goodyear tires overview.

Trailer King RST II ST235/80R16

Trailer King (part of TBC Corporation, founded in 1956) makes the RST II in both Load Range E and F for RVs, boat trailers and utility trailers. Some retailers also list older RST or “RST Plus” variants, so confirm the exact model and load index before you order.

Mastertrack All Steel ST235/80R16

Mastertrack’s UN All Steel line offers Load Range G (129/125) and H (132/127) for heavier loads. Speed ratings differ by listing (L or N), so check the sidewall if you tow at highway speeds.

RubberMaster RM86 ST235/80R16

The RM86 is a 14-ply, all-steel Load Range G tire rated for 4,080 lb. Retailers describe four wide tread grooves for water dispersal and reinforced sidewalls for load carrying.

Zeemax Fortress ST235/80R16

Zeemax Fortress I is an all-steel highway trailer tire sold in Load Range G and H. Compare warranty terms and the DOT date code with other brands before you buy.

Hi-Run ST235/80R16

Hi-Run ST100 tires are Load Range E with an 80 PSI rating, and are commonly sold as mounted tire and 8-lug wheel assemblies through farm-supply retailers.

ST235/80R16 Trailer Tire Price in 2026

Listings reviewed in 2026 ranged from about $139 to about $210 per tire, before shipping, mounting and disposal fees. Here are examples:

Prices change daily, so treat these as a snapshot. A useful trick is to compare cost per 100 lb of capacity. A $139.08 Load Range G tire (4,080 lb) works out to about $3.41 per 100 lb, while a $158.62 Load Range E tire (3,527 lb) is about $4.50. Capacity per dollar is not the same as quality, but it shows why a higher load range is not always the pricier choice.

ST235/80R16 Trailer Tire and Rim Fitment

The tire only works if the wheel matches. Most ST235/80R16 wheels are 16 inches in diameter and about 6 inches wide, with a center bore near 4.9 inches. The two bolt patterns you will see most are 8 on 6.5 inches and 6 on 5.5 inches.

Tire and rim assemblies

Many retailers sell mounted assemblies. That saves a trip to the shop, but check that the wheel’s own load rating meets or exceeds the tire’s. A Load Range G tire on a lightly rated wheel does not raise the trailer’s capacity.

Lug nut torque

Do not guess. Published torque specs vary widely, from about 90 to 100 ft-lbs on some 15-inch aluminum assemblies to 275 to 325 ft-lbs on certain 5/8-inch flanged-nut steel wheels. Use the wheel or trailer maker’s number, and re-check after the first stretch of driving.

Not sure who can mount and balance them? Browse local providers on our tire services page.

ST235/80R16 vs. ST235/85R16: Do Not Mix Them Up

The sizes look almost identical, but the sidewall is taller on the 85-series.

The extra height can rub fenders, change ride height and, if tires are mixed on a tandem, make one tire drag slightly. Change sizes only with the trailer manufacturer’s approval, and replace every tire on the trailer together.

How to Choose the Right ST235/80R16 Trailer Tire

1. Read the placard. Note the size, load range and axle rating.
2. Pick a load range with headroom. Use the worked example above.
3. Check the speed rating. Many trailer tire makers advise keeping speeds moderate even on higher-rated tires, so read the manufacturer’s guidance.
4. Compare warranty and construction. All-steel tires often suit heavier work.
5. Inspect the DOT date. Ask for tires made within the past year or two.
6. Confirm the wheel. Bolt pattern, center bore and wheel rating must match.

ST235/80R16 Trailer Tire PSI, Age and Maintenance

Correct PSI

Inflate to the maximum cold pressure printed on the sidewall for your load range. Typical figures are 80 PSI (E), 100 PSI (F), 110 PSI (G) and 110 to 120 PSI (H). Check with a gauge before every trip, when the tires are cold. A portable tire inflator makes this quick. Also remember that your truck’s dashboard monitor usually does not read trailer tires, so if a warning stays on, see why the low tire pressure light won’t turn off.

Tire age and the DOT date code

Trailer tires often age out before they wear out. Find the DOT code on the sidewall: the last four digits show the week and year of manufacture, so 3718 means week 37 of 2018.

• NHTSA notes that some vehicle and tire manufacturers recommend replacing tires 6 to 10 years old, regardless of tread.
• Many trailer specialists advise 5 to 6 years, especially for tires that sit in sun.
• Follow the tire maker’s and trailer maker’s instructions first.

Read more in our guide on how long tires last, and see the NHTSA tire safety page for official basics. Cracks in the sidewall are a red flag, so review our tire dry rot guide.

Tread and visual checks

New ST235/80R16 tires start around 8/32 to 11/32 inch. Measure with a tire tread depth gauge, and look for bulges, cuts, exposed cords and uneven wear. Check the spare too. It may look new and still be your oldest tire.

Repairs and storage

Sidewall damage is not repairable, and many shops are cautious about repairing trailer tires at all. If you have a tread puncture, ask a professional. For background, see flat tire repair cost and tire plug vs. patch. When parking a trailer for weeks, cover the tires from direct sun and re-check pressure before towing.

Where to Buy ST235/80R16 Trailer Tires

You have three practical options:

• Tire chains and local shops: convenient for mounting and balancing. Find shops by location in our state tire shop directory.
• Farm stores and trailer dealers: often stock E and G tires and assemblies.
• Online sellers: good selection, but inspect the DOT date on arrival. Tires can sit in inventory for years.

Common Mistakes When Buying and Using These Tires

• Buying on price alone without checking load range
• Mixing 80-series and 85-series tires
• Judging tire health by tread and ignoring age
• Running below the recommended PSI on long trips
• Forgetting the spare’s date code
• Skipping the wheel’s load rating and torque spec

ST235/80R16 Trailer Tire FAQ

Conclusion: Choosing the Right ST235/80R16 Trailer Tire

The ST235/80R16 trailer tire is a versatile 16-inch size, but the right one depends on your load. Start with the trailer’s placard, choose a load range with real headroom (E for lighter work, G or H for heavy hauling), and confirm the wheel, bolt pattern and PSI. Then buy from a source you trust, check the DOT date, and replace tires by age rather than tread alone.

Get those basics right and you will tow with fewer surprises and longer tire life.