Does a Spare Tire have to Match the Regular Tires on a Boat Trailer

Updated 10/03/2013 | Published 10/02/2013

Question:

I have a boat trailer with 4.80/4.00-8 tires. I recently had a marine store mount a spare tire on the trailer tongue. They used a 4.80-8 sized tire. The tires have different load and tire pressure max ratings, 590 at 60 lb and 780 at 90 lb respectively. Can I use the two different tires on the trailer at 60 pounds or must I get a different tire for my spare?

asked by: Keith S

Helpful Expert Reply:

Having a different rating and psi rating on a spare is permissible so long as you do not have to go far to get a new tire and as long as the capacity of that tire is enough for the capacity of the trailer. Ideally, your spare tire should be exactly the same as the regular tires to avoid any compatibility issues.

Not only should the spare be the same size, capacity, load range, and have the same psi rating but it should also be the same construction; either bias ply or radial.

Tire # AM10004 would be a great spare as long as the other tires on the trailer are 4.80-8, load range C bias ply tires rated for 760 pounds at 90 psi. I have included a link to our trailer tire FAQ article for you.

expert reply by: Michael H