Boat Trailer Tires Are Only Showing Tread Wear on the Outsides

Question:

I have an st205/75D14 boat trailer tires, can I replace it with a an st295/75R14? The tire wears out only on the outside from both sides. What could be wrong with the trailer?

asked by: Angel

Expert Reply:

Trailer axles usually have a bow in them at the center so the center of the axle is closer to the bottom of the frame than the ends. This causes the tires to camber in at the bottoms (positive camber). When a load is placed on the trailer that bow flattens out and the tires straighten. If the load is not heavy enough then it will not cause the axle to flatten out and the tires will still have a positive camber causing wear on just the outside tread.

Going to a wider tire would not solve the issue because the trailer would have the same problem just with wider tires.

In the event that the axle does not have the bow in it then you would want to check the suspension components to determine if something is misaligned or overly worn causing the problem. But if the issue is happening on both sides of the trailer it is likely that the boat is not heavy enough. When inspecting suspension components you will be looking for egg-shaped holes, obvious signs of excessive wear, and pretty much anything out of the ordinary.

expert reply by: Michael H