Every trailer tire size we stock, what it measures, what it carries, and a link to shop it loose or mounted on a wheel. Start by reading the sidewall of the tire on your trailer now: the size, the load range letter, and the max load in pounds are all molded into it. Replace with the same size and the same load range or higher.
Trailer tire size chart
| Size | Rim | Overall height | Section width | Load ranges we carry | Typical use | Shop |
|---|---|---|---|---|---|---|
| ST175/80R13 | 13 in | 24.1 in | 6.9 in | C (6-ply) | Jet ski, small boat, light utility | Tires | On wheels |
| ST205/75R14 | 14 in | 26.1 in | 8.1 in | C, D | Mid-size boat, single-axle utility | Tires | On wheels |
| ST215/75R14 | 14 in | 26.7 in | 8.5 in | D | Heavier 14-inch boat and cargo | Tires |
| ST205/75R15 | 15 in | 27.1 in | 8.1 in | C, D, E, G | The most common size: boat, utility, car hauler, camper | Tires | On wheels |
| ST225/75R15 | 15 in | 28.3 in | 8.9 in | D, E, G | Tandem-axle camper, car hauler, enclosed cargo | Tires | On wheels |
| ST235/80R16 | 16 in | 30.8 in | 9.3 in | E, F, G | Fifth wheel, gooseneck, equipment | Tires | On wheels |
| ST235/85R16 | 16 in | 31.7 in | 9.3 in | E, G | Heavy fifth wheel, dump, horse trailer | Tires |
| 215/75R17.5 | 17.5 in | 30.2 in | 8.5 in | F (16-ply) | Commercial equipment, tilt deck | On wheels |
| 235/75R17.5 | 17.5 in | 31.4 in | 9.3 in | G (18-ply) | Heavy gooseneck, dump, 12K+ axles | On wheels |
Overall height and width are nominal figures for a radial tire mounted on the standard rim width; a given brand may vary by a few tenths of an inch.
How to read a trailer tire size
Take ST205/75R15 as the example. ST means Special Trailer, a tire built only for trailers with a stiffer sidewall than a car or truck tire. 205 is the section width in millimeters. 75 is the aspect ratio: the sidewall height is 75 percent of the width. R means radial construction; a D in that spot means bias-ply. 15 is the wheel diameter in inches. After the size you will find the load range letter and the load index and speed rating, for example 107N.
You will see the same tire written as 205/75R15, 205-75-15, 205/75/15 or ST205/75R15. They are the same size. The ST prefix is what tells you it is a trailer tire.
Load range chart
| Load range | Ply rating | Max pressure | Shop |
|---|---|---|---|
| C | 6-ply | 50 psi | Load range C |
| D | 8-ply | 65 psi | Load range D |
| E | 10-ply | 80 psi | Load range E |
| F | 12-ply | 95 psi | Load range F |
| G | 14-ply | 110 psi | 14-ply, load range G |
Ply rating is a strength class, not a count of actual plies. The number that matters is the max load in pounds on the sidewall. To size it, add up the fully loaded weight of the trailer, divide by the number of tires, and buy a tire rated above that figure. Full guide: trailer tire load range and ply.
Shop by wheel size
13 inch | 14 inch | 15 inch | 16 inch | 17.5 inch
Shop by bolt pattern
5 on 4.5 (five lugs, 13 to 15 inch, axles to 3,500 lbs) | 6 on 5.5 (six lugs, 15 and 16 inch, 5,200 to 7,000 lb axles) | 8 on 6.5 (eight lugs, 16 and 17.5 inch, 8,000 lb and up)
Not sure which you have? Count the lugs, then measure center to center across the studs. Our bolt pattern guide walks through it.
Boat trailers
Saltwater eats painted steel. See boat trailer tires and wheels for galvanized assemblies in every size above, or galvanized trailer wheels on their own.
Three rules that prevent most trailer tire failures
Run the pressure printed on the sidewall when the trailer is loaded, not the pressure that feels right. Replace trailer tires at five to six years regardless of tread; the DOT date code on the sidewall tells you the week and year it was built. And never put a passenger car tire on a trailer, even if the size matches, because the sidewall is not built for the sway and heat of towing.