[Wavery]

In regards to using the old spare............trailer tires generally die from old age, not use. I would assume that the spare is the same age as the mounted tires. I would treat it in a similar manner (throw it away). Spares are actually worse off than the tires on the ground. As you tow your trailer, the vulcanized rubber in the tire is being self-vitalized as the oils in the tire sort of "Move-around" and lubricate the dry areas in the tire. As the tires age, the spare is generally the worse tire on the trailer. It doesn't have to show cracking on the surface. Most of the dry-out areas are internal.

As you now know.....it's quite common for someone to have a tire failure, install the spare, drive <100 miles and suffer another tire failure and have no spare to put on.

General rule of thumb........if you suffer a blow-out on a trailer that has 4+ year-old tires, install the spare and find the nearest place to buy 3 new tires. Remember, after the blow-out, you are far worse off than you were before the blow-out (you have no spare and the spare that you put on may be the next to blow).

Many a vacation have been spent in repair shop parking lots due to blow-outs and no spare.

BTW......Many rubber valve stems crack and fail far sooner that the tires, if the valve stem fails while you are on the highway, you won't notice the loss of air pressure before the tire blows apart, in most cases......

For those of you that have rubber valve stems, do yourself a BIG favor.....go out and bend the valve stem in every direction. If you see cracking, tow the trailer to the nearest tire store and have the valve stems replaced immediately. You should check rubber valve stems for cracking every time that you check your tire pressure. It's not uncommon for rubber valve stems to start cracking after 2 years of service.