Trailer Tires and overall weight

[Mako Shark]

I recently purchase a boat and trailer and was wondering if the size tires are adequate for the total weight. The boat is a 1975 Mako 15 and according to Mako's website weighs 850 lbs. It has a 70HP Johnson outboard and the trailer is a 1976 Cox trailer and everything looks like it was purchased together when new. The trailer has 5.7 x 8 class C tires on it which the side walls say 910 max weight. The registration for the trailer is rated at 3000 lbs which I thought was odd seeing that the tires are only suppose to have a max weight on them of 1820 lbs. I am curious to hear some thoughts.

 

[Silvertip]

Re: Trailer Tires and overall weight

The weight on the registration slip is not necessarily the gross vehicle weight rating (GVWR) or all up weight. It is merely a fee classification. In other words it may be that trailers in the 1500 - 3000 pound range pay the same fee. But you are observant and very correct in your concern about load and tire capacity. In your case, if the numbers are correct, you should be ok with those tires. The total load includes the weight of the trailer, boat, engine, fuel, equipments, and anything else you put it it minus the tongue weight because that is supported by the tow vehicle.

 

[Moody Blue]

Re: Trailer Tires and overall weight

Without knowing the trailer but judging by the year and size of boat, and the size of tires on it (the trailer ) I would guess that your trailer only has a 2000 Lb rated axle.

If you add up the total weight

boat 850
motor 250 (est)
battery 50
gas 50 (5 gal tank)
trailer 250 (est)
misc gear 100 (est)

you end up with 1550 Ibs. You are withing the capacity of the tires and more than likely the axle. The other consideration is the spring capacity. Not sure how to determine that.

Make sure you keep the tires inflated to the MAX rated pressure or you will end up on the side of the road with a blown tire.