You can minimize your chances of getting a flat tire by taking a few minutes to ensure proper inflation. Inspect tires when they are cool for cracks and spider webbing that occurs when rubber tires stay in one place for extended periods of time. Carry at least one spare tire assembly, and only replace radial with radial, bias ply with bias ply. Flat tire repair kits have proven their worth over the years for fixing flat tires caused by small punctures.
Improper bearing maintenance and lubrication account for most highway trailer breakdowns. At most ramps, boaters are forced to dunk their axle wheels and bearings in the water in order to unload the boat. When a warm hub is submerged in cold water, the air inside the hub contracts and draws water in through the best of seals. Once parked, the fresh- or saltwater will settle at the lowest point in the hub. This is where corrosion and rust begin. The next time the trailer is moved, the bad spot on the bearing may cause excessive heat and eventually total bearing failure. In the worst case scenario, heat can be intense enough to sever the axle and wheel.
The only way to eliminate water intrusion is to displace any possible air pockets with marine-grade grease. Bearing protectors apply slight pressure to the grease packing to help prevent water intrusion. Some hubs also help by providing lubricant at both the front and rear bearings without "repacking" the hubs. When on the road, make it a habit to check wheel hubs every time you stop for gas or a break. If the hub feels abnormally hot, the bearings should be inspected before continuing. Before a trip of any length, inspect your bearings for any signs of wear, rust corrosion, or heat damage and replace them if in doubt.