When it comes to RV safety, few components are as critical—and as overlooked—as your wheel bearings. Properly packed and lubed bearings are what keep your wheels spinning smoothly down the highway. If they fail, the results can be costly, dangerous, and even catastrophic. In this week’s Two-Minute Tech Tip Tuesday from the National RV Training Academy (NRVTA), we’re diving into how to inspect, clean, and repack your bearings the right way.
Why Bearings Are a Safety Concern
If you’ve ever seen an RV or trailer lose a wheel on the interstate, there’s a good chance the culprit was a failed bearing. Bearings that aren’t greased properly—or that go unchecked—can overheat, seize, and cause a blowout. In worst cases, a wheel can detach entirely, creating a major hazard for you and everyone else on the road. That’s why regular bearing inspection and maintenance isn’t just a “good idea”—it’s a must.
Step 1: Inspect for Play
When you arrive at a campsite or fuel stop, a quick check only takes a minute:
- Use a jack to lift the trailer slightly off the ground.
- Grab the tire at the sides and then at the top and bottom.
- If you feel any wiggle, your bearings may be going bad. If everything feels solid, you’re in better shape—but don’t stop there.
Pro Tip: Always support your trailer with jack stands under the frame, not the axle. Supporting the axle can cause it to bend.
Step 2: Remove and Inspect Bearings
- Take off the tire and hub.
- Pull out the bearings and inspect them closely.
- Look for pitting, black grease, or metal-on-metal wear. Healthy bearings should be well-lubed with red grease, not blackened or dry.
If bearings show signs of damage, replace them immediately. If they’re still good, clean them thoroughly using non-chlorinated brake cleaner or parts cleaner.
⚠️ Important: If using compressed air, blow from the inside out, and always drain water from your compressor tank. Rust-contaminated air can ruin a clean bearing.
Step 3: Packing Bearings with Grease
The right grease matters. Many RVers and technicians recommend red and tacky grease, which withstands temperatures up to 450°F—perfect for the heat bearings generate at highway speeds.
Here’s how to pack your bearings:
- Place a small amount of grease in your palm.
- Press the bearing into the grease repeatedly, rotating as you go.
- Continue until grease is pushed through the rollers and starts coming out the opposite side.
- Wipe off excess, apply a light coating inside the bearing, and spin it in your hands to ensure even coverage.
The goal isn’t to drown the bearing in grease, but to ensure every roller is fully lubricated.
Step 4: Reassembly
- Reinstall the race and bearing onto the spindle.
- Tighten the castle nut to 50 ft-lbs, then back it off to hand tight.
- Insert the cotter pin and reassemble the hub and wheel.
With everything torqued and secure, your bearings are ready for the road.
Step 5: On-the-Road Safety Checks
Every time you stop for fuel, make it a habit to check your axles:
- Touch each hub to gauge temperature.
- All hubs should feel roughly the same.
If three hubs are warm (around 200°F) but one is significantly hotter (say, 400°F), that’s a red flag—likely a failing bearing. Don’t ignore it. Jack up the trailer and inspect immediately.
Some axles have a zerk fitting (a small grease port) at the hub cap. This is for emergency use only. A couple of squirts from a grease gun may get you safely to an auto parts store, but it’s not a permanent fix.
Knowing Your Bearings
Most RVs use axles from Dexter or Lippert, each with specific bearing sizes and codes stamped on them. Before buying replacements, pull the old bearing and match the numbers, or record them ahead of time. Having the right part on hand can save you from being stranded.
The Bottom Line
Properly maintained bearings aren’t glamorous, but they’re critical for safe RV travel. A little grease, a few simple checks, and regular attention can save you from breakdowns, blowouts, and dangerous situations on the road.
Take the time to learn your RV’s axle system, practice safe bearing maintenance, and add this to your regular inspection checklist. It could be the difference between a smooth trip and a roadside disaster.
And there’s your Tech Tip.