Spare Tire Question?

What pressure do you keep your spare tire at?

I was filling up my tires the other day and I realized I hadn't checked the spare in a while and it was way lower than other tires, obviously, but without having to jack the trailer up and see what the pressures drop to under no weight, is their a general rule of thumb you guys follow?

Just inflate the spare to the max rating on the tire. Do this when it is not in the sun.

Originally Posted by rallyart

Just inflate the spare to the max rating on the tire. Do this when it is not in the sun.

Yeah I kind of figured that, I could always drop the pressure after I got it on the trailer. But why not in the sun? Does it play with elasticity and throw off the reading?

Originally Posted by chillinoj

What pressure do you keep your spare tire at?

I was filling up my tires the other day and I realized I hadn't checked the spare in a while and it was way lower than other tires, obviously, but without having to jack the trailer up and see what the pressures drop to under no weight, is their a general rule of thumb you guys follow?

Originally Posted by chillinoj

But why not in the sun? Does it play with elasticity and throw off the reading?

Yep, it increases the temp, which increases the pressure (PV=NRT).

pressure in the tire won't change just because the tire has a load on it.