Keep Your Spare Close: How To Install A Trailer Spare Tire Mount Properly

You’re ready for adventure, but is your trailer ready for a flat? A spare tire is useless if it’s not secure and accessible. Learning how to install a trailer spare tire mount properly is a critical skill for any traveler. This guide gives you the clear, step-by-step instructions you need to get the job done right the first time. We’ll cover choosing the right mount, finding the perfect location, and securing everything for safe miles ahead.

This main heading says it all. A spare tire mount isn’t just about convenience; it’s about safety and preparedness. A properly installed mount keeps your spare from becoming a dangerous projectile or getting stolen. It also ensures you can actually get to the tire when you need it most, potentially saving your trip from a major delay.

Why a Dedicated Spare Tire Mount is Essential

Many trailers come without a good spare tire solution. Tossing the spare in a storage compartment or strapping it down loosely are common mistakes. Here’s why a real mount is non-negotiable.

Safety: An unsecured tire can break loose in an accident or during hard braking. It becomes a major hazard for you and other drivers.
Security: A locked mount deters theft. Spare tires are valuable and easy targets if they’re just sitting there.
Accessibility: When you have a flat, you need to get to your spare quickly. A mount puts it in a known, easy-to-reach spot.
Space Saving: It frees up valuable interior storage space for your gear, not a bulky tire.
Tire Preservation: Keeping the tire mounted and off the ground protects it from UV damage, moisture, and dry rot.

Choosing the Right Spare Tire Mount for Your Trailer

Not all mounts are the same. Picking the correct one depends on your trailer’s design and your spare tire’s size.

Types of Trailer Spare Tire Mounts

Swing-Away Mounts: These are hinged, allowing you to swing the tire out of the way to access rear doors. They are ideal for utility and enclosed trailers.
Bumper-Mounted Carriers: These bolt directly onto your trailer’s rear bumper. They are simple and strong, assuming your bumper is rated for the weight.
Frame-Mounted Carriers: These attach directly to the trailer’s frame, offering the most strength and security. They are the best choice for heavier tires.
Undermount Carriers: These tuck the spare up underneath the trailer bed. They save space and keep the tire out of sight, but can be harder to access.
Side-Mount Carriers: These attach to the side of the trailer frame. They keep the rear clear and can offer good accessibility.

Key Factors to Consider

Tire Size & Weight: Ensure the mount is rated for your tire’s diameter and weight. Don’t guess—check the specs.
Trailer Construction: Do you have a strong steel bumper? A sturdy frame rail? Your trailer’s build dictates the best mounting points.
Access Needs: Do you need to open rear doors or a ramp? A swing-away might be necessary.
Locking Capability: Look for mounts with a built-in lock or the ability to add a padlock or lockable lug nut.
Material & Finish: Choose heavy-duty steel with a rust-resistant powder coat or galvanized finish for longevity.

Tools and Materials You Will Need

Gathering everything before you start makes the installation smooth. Here’s a typical list:

Your chosen spare tire mount kit
Spare tire and wheel
Wrench and socket set (sizes will depend on your hardware)
Torque wrench (very important)
Power drill with assorted bits
Metal drill bits (if drilling into frame)
Measuring tape and marker
Center punch
Safety glasses and work gloves
Penetrating oil (for rusty bolts)
Thread-locking compound
Touch-up paint for any drilled areas

Step-by-Step Installation Guide

Now, let’s get into the actual installation. Follow these steps carefully for a secure result.

Step 1: Determine the Mounting Location

This is the most important planning step. Consider these points:

Find a section of the main trailer frame or a reinforced bumper area. Avoid thin sheet metal or weak crossmembers.
Ensure there is enough clearance for the full tire. Check for interference with lights, jacks, doors, and the tow vehicle when turning.
Think about ground clearance, especially for undermount styles. The tire shouldn’t be the lowest point.
Make sure you can comfortably lift the tire into position and access the lugs for changing.

Step 2: Dry Fit and Mark the Mount

Don’t drill immediately. Have a helper hold the mount in your chosen location.

Position the mount exactly where you want it.
Use a level to ensure it’s straight, both horizontally and vertically.
Once perfectly positioned, use your marker to mark the center of each bolt hole directly onto the trailer frame or bumper.
Use a center punch to make a small indent at each mark. This prevents the drill bit from wandering.

Step 3: Drill the Mounting Holes

Put on your safety glasses. Drilling into steel can create sharp fragments.

Start with a smaller pilot bit, then step up to the final size recommended by the mount instructions.
Drill slowly and steadily, applying firm pressure. Use cutting oil on the bit to keep it cool and make drilling easier.
After drilling, deburr the holes with a file or larger bit to remove sharp edges. This protects the bolt threads and prevents stress points.
Immediately apply touch-up paint to the bare metal edges of each hole to prevent rust.

Step 4: Bolt the Mount to the Trailer

Now you’re ready for the permanent attachment.

Apply a small drop of thread-locking compound to the threads of each bolt. This prevents them from vibrating loose over time.
Insert the bolts through the mount and into the drilled holes. Add washers and nuts on the inside if accessible.
Hand-tighten all bolts first to align everything.
Using your torque wrench, tighten the bolts to the specification in the mount’s instructions. If none are given, a general rule for grade 5 bolts in steel is to torque to about 80-90 ft-lbs, but checking a torque chart is best. Do not over-tighten.

Step 5: Mount the Spare Tire

The final step is securing your spare.

Carefully lift the tire and wheel onto the mount’s studs or plate. It may be heavy, so get help if needed.
If using a swing-away, you might need to attach the tire before bolting the hinge mechanism to the base.
Secure the tire using the provided lug nuts or mounting hardware. Again, use a torque wrench to tighten the lug nuts to your wheel’s specified torque (often between 75-110 ft-lbs).
If your system uses a lock, install it now. Give everything a final shake test to check for movement.

Critical Safety Checks and Maintenance

Your job isn’t done after the last bolt is tight. Regular checks are vital.

Post-Installation Inspection

The Tug Test: Firmly try to shake the mounted tire. There should be no looseness, rattles, or flex in the mount itself.
Visual Check: Look for any cracks in the welds of the mount or stress marks on the trailer frame after your first trip.
Hardware Check: After 50 and 100 miles of towing, re-check the torque on all mounting bolts and lug nuts. They can settle.

Ongoing Maintenance Tips

Every few months, inspect the mount for signs of rust or corrosion, especially near the drilled holes.
Lubricate any moving parts on swing-away mounts with a dry lubricant to keep them working smoothly.
Check the tire pressure in your spare just as often as your main tires. A flat spare is as bad as no spare.
Before any long trip, make it a habit to visually verify the spare is secure and the lock is engaged.

Common Installation Mistakes to Avoid

Knowing what not to do is just as important. Steer clear of these errors.

Mounting to Weak Metal: Never attach a mount to the trailer’s thin exterior skin or a hollow tongue. Always find the structural frame.
Using Incorrect Hardware: Don’t substitute bolts with lower-grade ones. Always use the high-strength bolts provided or their equivalent.
Overtightening or Undertightening: This is why a torque wrench is essential. Overtightening can strip threads or crack metal; undertightening leads to failure.
Ignoring Clearance: Forgetting to check full turning clearance with the tow vehicle is a common and costly mistake that leads to collision damage.
Skipping the Lock: Leaving your spare unprotected is an invitation for theft. Always use a locking mechanism.

FAQ: Trailer Spare Tire Mount Questions

Q: Can I install a spare tire mount on any trailer?
A: Most trailers with a steel frame or reinforced bumper can accept a mount. You must verify the structure is strong enough to handle the weight and dynamic forces of towing.

Q: How much weight can a typical spare tire carrier hold?
A: It varies widely. Light-duty carriers may hold 75 lbs, while heavy-duty frame mounts can handle 150 lbs or more. Always check the manufacturer’s weight rating against your tire and wheel combination.

Q: Is it hard to install a trailer tire mount yourself?
A: With basic mechanical skills, the right tools, and patience, it’s a manageable DIY project. The hardest part is often drilling into the frame correctly. If you’re unsure about locating the frame or drilling, consulting a professional is wise.

Q: Should the spare tire match my trailer tires exactly?
A: Yes, ideally. The spare should be the same size, load rating, and bolt pattern as the other wheels. Using a different size can damage your trailer’s axle or brakes if used temporarily.

Q: How do I stop my spare tire mount from rattling?
A> Rattling usually means something is loose. Re-torque all bolts and lug nuts. On swing-away mounts, check the hinge pin and latch for wear; adjustment or lubrication often solves the problem. You can also place a rubber mat between the tire and the mount plate to dampen vibration.

Q: Can I mount a spare on the trailer tongue?
A: Sometimes, if the tongue is designed for it. However, you must ensure it doesn’t interfere with the coupler, jack, or electrical connection. Also, remember that adding weight to the tongue increases tongue weight, which must be factored into your overall loading calculations.

Final Thoughts on Securing Your Spare

A flat tire on your trailer dosen’t have to ruin your journey. By investing in a quality spare tire mount and installing it correctly, you turn a potential crisis into a minor inconvenience. The process requires careful planning, the right tools, and attention to detail, but the payoff is immense peace of mind. You’ll know your spare is safe, secure, and ready when you need it. Take a weekend to complete this important project—your future self on a remote road will thank you for it. Remember, the goal is to make sure your spare is always close, but never a concern.