Roadside Trailer Repairs: Carrying a Spare Hub and Changing a Hub or Tire Safely

Stop at the next safe place if you notice:

• A hub much hotter than the others when you check at a fuel stop (BoatUS lists this as a bearing warning; a dragging brake can also cause it)
• Grease slung on the inside of the wheel rim, the fender or the boat's hull near the wheel
• A grease cap that has popped off
• Grinding, growling or squealing from a wheel, smoke, or a burning smell
• The trailer wandering or a wheel visibly wobbling

A wobble or smoke means stop now, not at the next exit.

Signal, slow down gradually and pull as far off the road as you can, onto level, firm ground. An exit ramp, rest area or parking lot is far better than a highway shoulder. Turn on the hazard flashers. Put the vehicle in park, set the parking brake and turn off the engine.

If the failed wheel is on the traffic side and you can't get far enough away from traffic, don't work there. Call for help.

Put on a reflective vest. BoatUS suggests placing warning triangles or flares in a row starting about 100 feet behind the trailer. On a curve or hill, place them farther back so approaching drivers get warning. Keep passengers out of the vehicle on the traffic side, well away from the road.

Look at the problem before you commit:

• Flat tire: usually a roadside job if you have a good spare and a safe spot.
• Failed bearing, hub still on and spindle undamaged: a hub swap is possible if you have the right spare hub and tools.
• Hub came off, spindle is scored, bent or blue from heat, or the bearing has welded itself to the spindle: not a roadside job. The axle or spindle needs replacing. Call a trailer shop or roadside service.

If you have BoatUS Trailer Assist or Sea Tow Trailer Care, now is the time to call; both cover help with trailer flats and breakdowns within their limits (see our towing membership guide).

Chock the wheels on the side that will stay on the ground, front and back, so the trailer can't roll. On a single-axle trailer, chock the opposite wheel. On a tandem, chock the other wheels on the same side and the opposite side. Leave the trailer hitched to the vehicle.

With the wheel still on the ground, break each lug nut loose about a half turn, turning counterclockwise for standard threads. BoatUS reminds owners to loosen the nuts before lifting the wheel. Doing it in the air just spins the wheel.

• Tandem axle: a tire-changing ramp is the simplest and safest option. Drive the good tire on the same side up onto the ramp, and the flat or failed wheel lifts off the ground. BoatUS notes ramps only work on twin-axle trailers.
• Single axle (or no ramp): use a jack under the trailer frame, close to the wheel, on firm ground. Dexter recommends jacking only on the frame, not on springs, hangers or the axle tube, because those can bend and throw the axle out of alignment. Check your trailer maker's instructions for jack points.
• Lift only enough to get the wheel off. Put a jack stand or solid block under the frame if you have one. Never reach or crawl under the trailer.

1. Remove the lug nuts and pull the wheel off. Keep the nuts in a pocket or cup.
2. Fit the spare, making sure it's the right size and load range.
3. Thread all lug nuts on by hand, cone side toward the wheel if your nuts are tapered.
4. Snug them in a star (crisscross) pattern.
5. Lower the trailer, then tighten in a star pattern to the torque in your trailer or wheel maker's spec. If you don't have a torque wrench with you, tighten firmly with the lug wrench and get them torqued at the first chance.

If you're swapping a hub:

1. Remove the wheel (step 8).
2. Pry or tap off the grease cap (or bearing protector).
3. Straighten and pull out the cotter pin with pliers. Remove the spindle nut retainer (if any), the spindle nut and the washer.
4. Slide the hub off the spindle, keeping it level. The outer bearing may fall out; catch it if you can, so you can show the shop.
5. Brake axles: back off the brake adjustment if the drum won't slide off, and don't damage the brake wiring.

Wipe the spindle clean and look closely:

• Smooth and evenly colored: OK to fit the spare hub.
• Scored, pitted, bent, blued from heat, or with the old inner bearing or seal stuck on it: stop. BoatUS says spindles and bearings must be perfectly smooth; a damaged spindle will quickly ruin a new hub. Call for a tow or a trailer shop.

Make sure the old inner seal and any bits of bearing came off with the hub.

1. Put a light coat of grease on the spindle where the bearings and seal sit.
2. Slide the new hub on straight and gently so you don't damage the seal.
3. Fit the washer and spindle nut.
4. Set the bearing adjustment exactly as the hub kit's instruction sheet says. The general method BoatUS describes: tighten the nut while turning the wheel to seat the bearings, then back it off slightly and lock it with the cotter pin. Don't guess at a tighter setting; overtight bearings overheat.
5. Use a new cotter pin and bend its legs over. Tap the grease cap on squarely.
6. Refit the wheel and lug nuts as in step 8.

Remove the chocks only after the trailer is back on the ground and everything is tight. Collect the triangles. Then:

• Drive slowly for the first few miles and stop at a safe place.
• Carefully feel near each hub (back of your hand close to it first; a bad hub can be very hot). The new hub should be no hotter than the others.
• Recheck lug nut tightness. Dexter explains that trailer wheels need re-torquing several times after mounting until the torque stabilizes, so follow your trailer or wheel maker's re-torque schedule.
• If a hub runs hot, stop and recheck the bearing adjustment, or get help.

• Replace the spare hub and spare tire before the next trip.
• Have the trailer shop check the other hubs. Bearings of the same age often fail close together.
• Consider bearing protectors or an oil-bath/sealed hub upgrade (see our hub upgrade guide).
• Check the brakes on that wheel if it ran hot.