Boat Trailer Tires And Wheels: Maintenance, Parts And Tire Pressure.

Boat trailer tires and wheels are an often neglected part of your boating package.

How many times have you heard stories of grief about seized wheel bearings, blown tires, flats with no spare?

The tires, wheels and bearings on your trailer do need a little attention to be kept in top working order, but it is worth it.

I often read articles which recommend repacking your bearings every 6000 miles or 10,000 miles. I know I don't track how far I have towed my trailer since last time I repacked the bearings.

So, I keep it simple.... I maintain my boat trailer tires, wheels, and bearings every spring, and keep an eye on them throughout the boating season to make sure there are no issues.

I do use "Bearing Buddies" on my hubs, so a shot of grease now and then insures there will be no seized bearings in my life.

The important points to check around the wheels on your trailer:

  • boat trailer tire pressure - is it correct
  • tread wear on tires for boat trailer - if they are worn out replace them
  • boat trailer spare tire - make sure you have one and it is correctly inflated
  • boat trailer hubs - when were they last greased?
  • boat trailer fenders - make sure they are not bent or rubbing
boat trailer tiresWhy trailer specific tires?

Boat trailer tires are designed to support the weight of the trailer and boat for many miles with a minimum amount of bounce. Trailer tires generally have stiffer side walls than passenger car tires, to support weight without flexing, because ride comfort is not as important.

Trailer tires are also designed to have lower rolling resistance than vehicle tires by using harder rubber compounds. The harder rubber compounds increase the life of the tire but decrease the traction. Since a trailer simply follows the tow vehicle, traction on a trailer is not an issue.

Radial vs Bias Ply Tires

Radial tires have radial reinforcing belts set at 90 degrees to the direction of travel and more belts wrapped around the tread area of the tire. This allows the sidewalls to flex seperately from the tread area which reportedly means longer tire life, better trailer tracking, as well as a better ride.

Bias ply tires have the reinforcing belts set at a 45 or 30 degree angle to the direction of tire travel, which some say gives the tire more resistance to damage, but the tread area of the tire does change shape on the road surface as the tire sidewall flexes, which decreases traction, and tracking of the trailer.

Radial tires are the tire of choice for passenger vehicles, but bias ply technology is a popular choice for boat trailer tires because they are significantly cheaper.

Load Ratings

Tires are given a load rating letter or a number of plies to indicate strength of the sidewalls. The number of plies is based on the number of plies bias ply tires of equivalent strength used years ago. Neither of these rating systems tell you how many fabric or steel plies are in a modern tire. Modern bias ply and radial tires don't need to use this many plies to achieve the given load rating.

The letter is the new load rating and the number of plies indicated is a comparison with the older bias ply load rating system.

B=4ply, C=6ply, D=8ply, E=10ply, F=12ply, and G=14ply

The trailer tires on my RV are radials with a load rating of B, and they have only 2 polyester plies in the sidewall. The bias ply tires on my boat trailer have a load rating of B and also have only 2 polyester plies.

The size of the tire must also be taken into account when looking at how much the tire can carry. Larger tires of the same load rating will be able to carry more weight. Tires are marked with their maximum safe load.

Tire Manufacturers

There are many manufacturers of trailer specific tires. A few that I know of are:

  • Carlisle
  • Duro
  • Titan
  • Towmaster
  • Vredestein
  • Countrywide
  • Goodyear
  • Loadstar
  • Trail America
  • Kumho

Protecting from cracking

No matter which type of tires you choose, a common problem with trailer tires is cracking. Trailers typically sit for extended periods of time and it is easy to forget about them. After a few years of UV exposure, they begin to crack, so even though there may be lots of tread wear left, the tires may be no longer serviceable.

Protecting your tires from UV light during the off season is a good idea. (I admit I do not do this) Another option is using some type of protectant on the rubber. I do treat the rubber tires when I treat my inflatable boat..... I hope it gives me the desired effect of extended tire life!

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