Trailer Tire Pressure

Mark W

Mark W

Well-known member
I know this has been discussed before and I searched through the threads. A couple were even mine.

I had purchased new tires for my duck boat trailer before last season. A couple weeks back I noticed one had gone flat. Sure enough, a small pinhole caused the leak and the tire was unrepairable.

Had the new tire mounted yesterday and I was asked what pressure I wanted it inflated to to which I replied 50psi. When I picked up the tire, the manager said the tire says it is rated for 90pshi and was I sure I didn't want the pressure higher. I asked what pressure he would recommend and he said 90psi.

This just seems really high to me. The total weight on that trailer is well under the recommended maximum load capacity. I would guess somewhere near 225lbs total including motor and gear. I really don't want to over inflate or under inflate. Tire size is 4.80 X 12

Any tire experts here that care to weigh in?
 

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I usually run my trailer tires at 25psi! Similar to you my loads are far lower the rating of the trailer. I use the tires to compensate for the springs some. On the big boat, I do run higher, but not 90. Like you 50 psi is the max. I generally don't run long distance, and when I do , I check the tires, and hubs after a few hours just to make sure all is well. So far, my wear has been typical, and the tires dry rot long before they wear out.
 
I run my 4.80 X 12 tire4s at 35 psi, I bet my whole rig is less than 500 pounds as well.
Ask 10 people about trailer tire pressure and get 10 answers!
 
Your tire is designed to be run at the higher pressures. Fill it up. Generally speaking, trailer tires need to be run at/near capacity to maximize tire and tread life. If you run a 90 psi tire at 50 psi, you're reducing the load it can handle by 40-50%. Probably not an issue in and of itself given your boat/trailer weight, but remember a load range C is "lighter load" to start with and has fewer plies, meaning it is relying more on internal pressure for structure.
 
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What Henry said. If you decrease the pressure more than 10%-15% below maximum you can expect accelerated tire wear with more likelihood of a flat. Small tires generally need higher pressure to retain an efficient shape, i.e. not running with a flat spot and bulging sidewalls. Follow the manufacturers recommendations. Don't play test pilot on public roads, somebody else can get hurt when a trailer goes AWOL.
 
For automobile tires I have used a combination of the 4psi rule and what the door sticker says. Trailer tires I have always used the tire pressure indicated by the manufacturer decal located on the inside of the frame. I have tried the maximum tire pressure but damn, it rides like a rock wagon! Like you said, ask ten people and get ten different answers. RM
 
RM Anderson said:
Like you said, ask ten people and get ten different answers. RM
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Asking 10 people is the mistake... ask your tire or trailer person. There are trailer tires that don't require high air pressures - but if you choose high air pressure tires then please use the correct air pressure - if not for your and your gear's sake then for yhe rest of us on the road.

And, no, I'm neither a tire nor trailer expert. But I've had this conversation with enough who are to be confident that there are not multiple correct answers to this question (regardless of how many answers are offered).
 
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