To run profitably with a GVWR under 26,000 the objective is to take as much curb weight out of the set up to maximize payload. Simply put a tri-axle trailer is lighter by about 500 pounds than a twin dually trailer, and therefore will allow for a higher pay load.
The problem with tri-axle set up is they require an ongoing maintenance vigil. Kaufman trailers the largest 3 car trailer manufacturer in the US recommends re-packing tri-axle bearings every 10-12,000 miles. For a full time rig that is every 5-6 weeks! But in our experience a disciplined tighten and re-pack schedule every 5-6 weeks is NOT enough, and maybe too short under certain conditions.
Tri-axle bearings are placed under pressure on every turn. Similar to a wind-shear, the bottom of the wheel is often under a side force opposite to the top of the wheel. We have observed a wheel torqued out at the bottom or top by as much as 1-2 inches under a sharp turn. This is because the center wheel is the pivot point on the turn, while the front and rear wheels are literally dragged across the pavement. Even a modest turn under a heavy load will leave a tire skid mark on dry pavement an indication of the front or back tires dragging across the pavement. The shearing action caused by turns can loosen bearings and more importantly loosen seals allowing grease to leak out and away from the bearing.
Tri-axle wheels need an ongoing observation strategy to avoid problems. There are 2 ongoing checks while on the road that can smoke out imminent wheel bearing problems.
- Check your wheel bearing operating temperatures at least once a day. This is a quick check that can be done at any stop. Park and immediately walk back to the trailer and briefly touch each wheel hub. If the hub is slightly warm or less, the bearings are fine. If the hub is too hot to hold, that bearing is running too hot and needs attention. A hot running bearing is caused by not enough grease in the bearing. There could be several reasons why the grease is gone or broken down, but a couple shots from a grease gun can resolve the hot bearing. If a seal is broken a shot of grease will only provide a short term fix, but could keep you on the road, and prevent a total breakdown of the bearing.
- At some point on each trip you will have a moment when the trailer is parked and empty. Inspect each trailer wheel with a “wiggle test” by grabbing the top of each wheel and pulling firmly outward. The wheel should be tight and have no internal play or “wiggle.” A slight wiggle is not an immediate problem. Experience will help a driver diagnose the severity of a loose bearing, severe or not a wiggle in a wheel is an imminent future problem that should be scheduled for service.