tire pressure for trailer

M

mikestein

New Member
Jun 5, 2007
129
Columbia, SC
I am taking my boat on it's longest trip tomorrow... about 150 miles. The tire pressure is 27 lbs. Max pressure is 50. What should I have? I've got a 185 that weighs in about 3000 lbs with fuel and gear. The trailer is another 1200 -- I think. It's a shorelandr.
 
I had four new 15" tires put on my trailer a few months back and they are at 50psi.
 
Not 100% sure if it is right but I set mine to 48. I figure when trailering they build up a little heat. Someone will correct me if I am wrong and if so I hope they do, so I can fix it. Mine sit in the garage so they are always cold before starting and always seem to be down a pound or so. :smt017

Wesley
 
Ah, the trailer tire discussion again. :grin:

First off, tire pressure should be checked cold. I mean not even sitting in the sun. Cold pressure is what the rating is on the sidewall. If you should run 50 psi, run 50 psi cold. Yes it'll heat up some but running it lower will heat it up more. 27 psi is dangerous.

Also, ST tires are rated at 65 MPH max. If you're planning on driving faster than 65 MPH, you go up to as high as 60 psi with ST tires that are rated for 50 psi.

Direct from Goodyear:
"Based on industry standards, if tires with the ST designation are used at speeds between 66 MPH and 75 MPH, it is necessary to increase the cold inflation by 10 PSI above the recommended pressure for the load".

http://www.goodyear.com/rv/pdf/rvbrochure.pdf go to page 9 to the "Important Operating Information" for the whole piece.

As for what psi you should be running, I don't know what size tires they are but I assume it's single axle. You should find a load range chart on Goodyear's web-site that will tell you what you should have them inflated to for you're load. Depending on how the trailer rides, I'd be inclined to run them at 50 psi.

The Goodyear site has a lot of good information on ST tires. They aren't like car tires and aren't used like car tires. They don't last like car tires. In my case I'll replace all 4 every 3 years max. and I do things like rotate each tire 1/4 turn if it's sitting for more than a month at a time and I check the psi each time before pulling it out of storage. I've waited then checked and found the side facing the sun were at a higher psi after sitting in the sun for a few minutes. I found the same thing with my truck.

I'm anal about trailer tires especially since mine are at the ragged edge of their total capacity. I've only lost 1 tire on the HWY and it separated but didn't blow. I'd just had 2 others replaced due to tread separation that I caught before they came apart. They had sat for 7 months in almost the same place outside in the weather. That killed them. See comment about 1/4 turn once a month above. It's because the oils in the rubber will settle and leave the top drier and then they come apart when they start getting used and heating up. Another tip from a guy from Goodyear that turned out to be true.
 
Thanks Jim, I thought that may be the case. I was hoping you would answer this one!!! :thumbsup:

Wesley
 
Sea Ray Jim said: I'm anal about trailer tires especially since mine are at the ragged edge of their total capacity. I've only lost 1 tire on the HWY and it separated but didn't blow. I'd just had 2 others replaced due to tread separation that I caught before they came apart. They had sat for 7 months in almost the same place outside in the weather. That killed them. See comment about 1/4 turn once a month above. It's because the oils in the rubber will settle and leave the top drier and then they come apart when they start getting used and heating up. Another tip from a guy from Goodyear that turned out to be true.

Jim, Could it also be from the sun dryrotting the tire, and if it were covered, would it help? Allot of camping people cover their tires during storage.
 
I run my tires at 50, I check tires and hubs when I stop, I make several stops in trip, sometimes just to check, they are always just slightly warm.
 
It's a good thing I asked.... It might have been a long trip at 27 lbs, or more likely, 0 lbs after a few miles. Anything else I should be looking at, bearings etc?
 
I have bearing buddys on my trailer, I always make sure that I have enough grease to push the cap out against the spring, do not compress the spring all the way, it needs to have expansion room, would not hurt to pull and check at least once a year, replace seal, clean, inspect and repack bearings with fresh grease. Make sure you have a spare tire, lug wrench and jack for the trailer, just in case. I know there is more I just can't think of it right now.
 
A few other trailer tire ideas.

1. Don't store long term on concrete. Put a piece of wood/plywood under each tire. Especially if you can't rotate them the 1/4 turn from time to time as recommended by Jim.

2. For off season storage consider jacking up the trailer/boat so the tires are completely off the ground and securely supporting the trailer/boat with several jack stands. I read that was a recommended procedure but my mechanic said it was overkill. I still think I'm going to do it this autumn.

3. Next time you buy trailer tires, consider moving up one level in load range. I did that this year. It just gives me a bit more peace of mind and didn't cost much more at all.

4. If your trailer is stored in the sun, consider ways you can get it in the shade. Or put covers over just the tires to keep them out of the UV rays.
 
Sea Ray 300 said:
Jim, Could it also be from the sun dryrotting the tire, and if it were covered, would it help? Allot of camping people cover their tires during storage.
Click to expand...

The tires were less than a year old and it wasn't dry rot, but you are correct that it was from the sun and the elements. They sat in one place for a long time (it was moved a few times but still had a few months on one place) and the heat, sun etc. caused the oils to settle which left the top of the tire drier. That was evident when I put all that together and when the first 2 tires were found separated (out of round and funky looking) it was on one place on the tire, and the one that came apart was the same deal as you could see where the tread was not "adhered" like it was the rest of the way around. The tread and the tires otherwise looked new still.

So yes absolutely cover them if they are outside, but the heat/cold and sitting in the same position is also just as much of an issue. The covers will help prevent dry rot and slow down the settling of the oils in the rubber. Cover and spin 1/4 turn at least monthly.

Also, most TT's that sit will be up on jacks so there is no weight on the tires which is also good. The guy with Goodyear said that they just found that it was not as easy to do with boat trailers which is the only reason why it's not done much with them.

If you browse around Goodyear's site, also notice they say to over inflate the tires if they are going to sit for a long time.

A note about the Goodyear site, most of what they say is industry standard and applies to all ST rated tires but they just put it all right there easier to access.
 
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