Correct Tire Pressure for 5.30x12 Trailer Tires

Question:

Max air pressure is 80 psi with a load of 1085lbs. My trailer alone is 1300lbs. The tires are the right size for the trailer.... What is the best tire pressure.. Im currently running at 65psi

asked by: Michel C

Expert Reply:

In order to realize their full weight carrying capacity, trailer tires should remain at their maximum pressure as stated on the tire's sidewall. When fully pressured up, your current tires have a capacity of 2170 lbs per axle. When you subtract the 1300 lb weight of the trailer, you're only left with 870 lbs for payload. Running at a lower pressure rating reduces the weight capacity of your tires, but the actual capacity is unknown because the tires are tested at the recommended full pressure. So, I'd recommend keeping them inflated to the full pressure rating of 80 psi.

If that load rating is insufficient, you could go with a ST145/R12 load range D radial tire like # AM10130 which has a 1220 lb rating per tire or 2440 lb per axle weight capacity when properly inflated to 65 psi. This leaves you with 1140 lbs of payload capacity. This assumes that your trailer has a GVWR equal or greater to 2440 lbs. This tire is roughly the same size as your current tires, so you won't have any fender or frame clearance issues and it'll fit your current wheels.

The tire is also available mounted to a white painted 12x4 wheel with a 5 lug/4-1/2 inch bolt circle as part
# AM31199DX.

expert reply by: Mike L