How to Select Appropriate Trailer Tires for Boat Trailer Carrying 6000-lb Boat  

Question:

Helpful Expert Reply:

We can help you select appropriately-rated tires for your boat trailer.

The best place to start is the trailer's primary information sticker that typically has its VIN, axle ratings, etc. Look for the GVWR figure; this is the most the loaded trailer can safely weigh, including the boat, of course. I also suggest checking with the maker of the boat (using its VIN) to confirm its exact weight; this will ensure that the trailer itself, independent of the tires used, has the required weight-carrying capacity for the craft.

Once you know the trailer is up to the task of transporting your specific boat, take the trailer's GVWR and divide this weight figure by the number of tires on the trailer. If single-axle divide by 2; if tandem axle, divide by 4. This calculation tells you the load each tire needs to be able to handle.

Safety margin is important in any trailering component but especially so in tires. Ideally you will select tires that EXCEED the actual per-tire load that will be on them.

For instance, let's say your trailer by itself weighs 1500-lbs. When we add this to the boat's own 6000-lb weight we have a total of 7500-lbs. If your trailer is a tandem axle this means each of the four tires will see a load of 1875-lbs. If a triple-axle trailer with 6 tires then each would see a load of 1250-lbs.

The trailer tire size you referenced, ST235/80-16, is offered in a radial type in several different weight load ranges, Load Range E and Load Range G. All tire options in this size are shown on the linked page. The excellent Taskmaster tire you referenced, Load Range E tire # TTWTRTM2358016E, has a per-tire weight-carrying capacity of 3520-lbs at its rated 80-psi pressure. This tire also offers a high speed rating, an M rating of 81-mph maximum, which is also an important feature since some trailer tires cannot be operated this fast without excessive heat build-up. In a Load Range G tire we have the Taskmaster Provider # PRG80235 which can handle 4080-lbs at its rated 110-psi pressure. This too carries an M speed rating.

It is perfectly fine to use tires that are rated for much more weight than you're actually going to put on them; this simply means they will run cooler, a good thing.

The main cause for a trailer tire to fail is excess heat. This can come about from several causes: overloading the tire beyond its weight rating; operating it with incorrect inflation pressure; or operating it at a higher speed than what it is rated to handle.

Trailer tires should always be inflated to the maximum psi pressure that is indicated on the tire sidewall. It is never appropriate to under- or over-inflate a special trailer tire for any reason. Tire pressure should be checked and maintained with the tires cold; they will naturally warm up as you drive but you do not have to compensate for this. Cold pressure is what matters.

I linked two helpful articles on trailer tires that may be of interest to you. And if there are any remaining questions or concerns please do not hesitate to reply to this email for further assistance.

expert reply by: Adam R

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