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.... view full answer...