Is There a Formula for Determining Air Pressure in Trailer

Published 03/14/2019

Question:

I have a PWC trailer that is rated for 1700lbs and has 5.30 -12 tires load range C which can have a maximum of 80psi. My issue is that I will only ever have a RIB on it which weighs about 360lbs. So even with fuel and any other gear Im likely never going to have more than a 400lbs load. Presently with 65psi I can put my finger underneath the first row of tread blocks. These tires have 5 rows of tread blocks and when viewing the tire tread only the centre row is really making full contact with the road surface. the other 4 rows are not in full contact with the ground. These tires will likely be wearing out in the centre. The trailer is also very bouncy with this pressure. I dont want to risk a tire problem by reducing inflation but having them at maximum tire pressure with such a light load doesnt seem correct either. Can I safely reduce the pressure so I have better contact with the ground or is their a formula to calculate pressure based on the actual load on the trailer vs maximum load?

asked by: Ray

Expert Reply:

There is no special formula for tire pressure in regards to the load of your trailer as you normally want to inflate the tire to the maximum cold psi for the best performance.

However, if you are not getting that, and your trailer is bouncing then you can try reducing the air pressure on a 5.30R12 tires like the Taskmaster # TT53012C which like your tire, has a max of 80 psi. The maximum capacity of these load range C tires is 1,050 lbs each so if you have the same or similar tire you can certainly reduce the air pressure without risking lesser capacity.

If you have bias tires, I do recommend switching to radial tires like the aforementioned Taskmaster. The reason is that radial tires are designed specifically to flex more than bias tires to give you better ground contact because bias tires have a stiffer sidewall.

I've added a link to a video review of this tire for you to take a look at as well.

expert reply by: Kyle S