Spare Tire Kit for a Travel Trailer: Carrier, Jack and Lug Wrench
A spare is only half a roadside plan. Build the kit around it: a secure carrier, a jack that suits a trailer, a lug wrench that fits and a way to tighten the nuts properly.
A travel trailer roadside kit needs five things working together: a spare that matches and is in date, a secure carrier, a jack that suits a trailer, a lug wrench that actually fits your nuts and a way to tighten them to your manual's value afterward. Check each one at home, because the roadside is a poor place to learn that the wrench is the wrong size.
This guide is about the gear. For keeping tires from failing in the first place, see our guides to blowout prevention and tire care and safety.
Start With the Spare Itself
NHTSA points out that spares age even when they are rarely used, because they are seldom replaced, and says to check the pressure of every tire, including the spare, at least once a month. Age does not show in the tread, so read the DOT code on the sidewall: the last four digits give the week and year of manufacture, and NHTSA says some manufacturers recommend replacing tires between six and 10 years old regardless of wear.
Match what is on the trailer. Wikipedia notes that ST stands for special trailer, so read the full size and load markings on your tires and the trailer's label, then buy a spare with the same size and construction. Wikipedia also describes limited-use spares for cars as meant for short distances; do not assume that idea carries over to a trailer, and ask the trailer or tire maker about any odd-size spare.
Look at the spare as you would any tire: cracks in the sidewall, a bulge, a damaged bead area or a valve stem that has perished are all reasons to ask a tire shop for advice. If the spare has sat outside for years, treat it as suspect even if it never touched the road, and consider a cover that keeps it out of direct sun.
The Carrier and Mount
A spare that falls off helps nobody. A carrier should be designed for your trailer's frame or spare mount, fit the wheel pattern you actually have and hold the tire without rattling. Look for rust, cracked welds and loose hardware each season, and keep the spare dry and out of long direct sun when you can. Ask your trailer maker what a factory mount is designed to carry before you add a different one.
The Jack: Where Plans Fail
A jack that was fine for a car may not suit a trailer. Dexter's service manual says to support a trailer only on manufacturer-approved points, never on the axle or suspension, and never to get under a trailer unless it rests on jack stands rated for the load. So you need to know the following before you buy:
- Where your trailer maker says it can be lifted, and where the jack will actually sit.
- Whether the jack's stated rating suits your trailer. Read the maker's rating for the jack and the trailer's numbers on its label.
- How much lift it has, since a flat tire sits closer to the ground and a loaded trailer sits lower than an empty one.
- Whether you need blocks or a flat base to stop it sinking into soft ground or gravel.
The trailer's wheel chocks also matter. See our wheel chock guide for the options, and always chock before you lift.
Lug Wrench and Torque
Check the socket size on your lug nuts before you leave. A cross-style wrench is quick, and a breaker bar and socket give leverage for stubborn nuts. Then plan how you will tighten them. A torque wrench is the right tool for tightening to the number in your manual, and Dexter's manual calls for torque checks soon after wheels go on, so schedule a re-check after any roadside change.
The Rest of the Kit
| Item | Why it earns a spot | Check first |
|---|---|---|
| Jack stands | Safer support while the wheel is off | Rated for your trailer |
| Wheel chocks | Stop rolling while lifting | Fit the tire size |
| Tire gauge and inflator | Set the spare's pressure | The pressure your label lists |
| Gloves and flashlight | Roadside conditions are rarely ideal | Batteries in date |
| Wood blocks or base plate | Spread the jack's load on soft ground | Stable and dry |
| Reflective triangles | Make you visible | Stored where you can reach them |
Our guides to portable air compressors and the RV tool kit cover related gear.
Practice Once at Home
Do a dry run on level ground with the trailer unhitched or chocked as the maker directs. Take the spare off its carrier, find the lift points, loosen a nut or two and put them back. Note what is stiff, missing or too short. Write the torque value and tightening pattern on a card in the kit, and keep the manual page handy.
When to Call for Help
If you are on a narrow shoulder, the ground is soft, the nuts will not move or you are unsure where the trailer can be lifted, call roadside service. A kit improves your odds but it does not make an unsafe spot safe. After a roadside change, have the tire, the wheel and the hub checked by a shop, especially if the failure took out a fender or the axle.
New or Used Gear
Hand tools such as wrenches, sockets and breaker bars are reasonable to buy used if they are straight, unrusted and fit properly. Be more careful with anything that holds weight. A jack or jack stand with a bent frame, cracked weld, stripped thread or missing pin should be skipped whatever the price, and a rating you cannot verify is a reason to buy a different one. A torque wrench needs to be in good condition and stored as its maker directs, since a dropped or neglected one may not read correctly.
Where the Kit Lives
Keep the wrench, socket and gloves together in one bag or bin where you can reach them without unloading the bay. A tongue box or a front storage compartment can work; see our guide to tongue boxes and exterior storage. Do not bury the jack under camp chairs. Check the contents before each season and replace anything rusted, cracked or missing.
Common Mistakes
- Assuming the spare is fine because it looks new. Check the date code and pressure.
- Carrying a wrench that does not fit. Test it on a lug nut at home.
- Lifting at the wrong spot. Find the approved points in your manual first.
- Working under a trailer held only by a jack. Use stands rated for the load, as Dexter's manual directs.
- Forgetting the re-torque. A roadside change is not finished until the nuts are checked.
Read for this guide: NHTSA's tire safety page (spares age even when rarely used; check the pressure of all tires, including the spare, at least monthly; the last four digits of the DOT number give the week and year of manufacture; some manufacturers recommend replacing tires at between six and 10 years old regardless of tread; the page is written for vehicles and does not cover trailers); Dexter's Light Duty axle service manual (support a trailer only at manufacturer-approved points, never go under it unless it rests on jack stands rated for the load, check wheel nut torque early and follow the manual's values, and contact a qualified mechanic if a problem cannot be resolved); and, as secondary background, Wikipedia's tire code article (ST means special trailer; how the DOT date code works) and its spare tire article (full-size versus limited-use spares).
No inflation pressures, torque values, jack capacities or tire load ratings are quoted, because they depend on your axle, tires and trailer. Use your trailer's label and manual, the axle maker's instructions and the tire sidewall.
Frequently Asked Questions
How often should I check my trailer's spare tire?
Check the spare on the same schedule as the others. NHTSA says to check the pressure of all tires, including the spare, at least once a month. Look at the sidewall, the carrier and the age code too, since a spare can age on the rack without ever wearing its tread.
Can I use my truck's jack to change a trailer tire?
Only if its maker says it suits the job. Dexter's manual says to support a trailer only on manufacturer-approved points, never on the axle or suspension, and never to go under a trailer unless it is supported on jack stands rated for the load. Check your trailer and jack manuals before relying on any jack.
Do I need a torque wrench for a roadside change?
A torque wrench is the right tool for tightening wheel nuts to the number in your manual. Dexter's manual calls for checking wheel nut torque early on a new axle, and a roadside change deserves the same follow-up as soon as it is practical. Your trailer or axle manual lists the value and the pattern.
What does ST mean on a trailer tire?
ST stands for special trailer, according to Wikipedia's tire code article. A spare should match the size, load rating and construction of the tires it replaces, so read the sidewall and the trailer's label rather than guessing.
How old is too old for a spare?
The last four digits of the DOT code show the week and year of manufacture. NHTSA notes that some manufacturers recommend replacing tires at between six and 10 years old, regardless of tread wear. Check what your tire maker and trailer maker say.