Trailer Tire PSI?

[Andyfender]

Size of tire = 5.30-12
On the sidewall of the tire it states "Load 1050 Mas Psi 80 psi.

Should I really inflate these to 80psi? Presently I have them at 55 psi.

 

['78 Crusader]

Re: Trailer Tire PSI?

Not unless you're running the max weight the tire is rated for. I'd run it At 55-60 psi as you've stated.

That's what I'm doing with my similar tires on the Whaler.

 

[paultjohnson]

Re: Trailer Tire PSI?

Personally, I would bump 'em up to about 70#s cold. Makes the tire stiffer and you will have less trailer...sway. I have followed people pulling trailers w low tire pressure and the trailer sways back and forth alot more. Sure cant help your mileage or safety. I say 70#s cuz that give you a little leeway when your tire gets warm and pressure goes up because of it.

 

[BaileysBoat]

Re: Trailer Tire PSI?

You need the 80 PSI or the tires will run hot and fail. At 55 PSi too much sidewall flex = heat.
The air carrys the load.

 

[bigdee]

Re: Trailer Tire PSI?

You need the 80 PSI or the tires will run hot and fail. At 55 PSi too much sidewall flex = heat.
The air carrys the load.

YES BaiylsBoat is correct......If tire says 80 then put 80 in it. Most trailer tire failures are from UNDER-INFLATION.

 

[JB]

Re: Trailer Tire PSI?

Nobody has mentioned the weight of the load. It is essential to make any statements about what would happen. You need 80psi to carry the full rated load of the tire.

If you run lower pressure you degrade the load capacity of the tire. 50psi would probably be okay if your load is 700#, but as deadly as predicted IF you are running a 2000# load.

There is no downside that I know of to running the tires at max rated pressure. That is what I would do.

 

[jimbo_jwc]

Re: Trailer Tire PSI?

Had some AM General Bomb Cart tires that were 10 ply with same psi . Not sure if i aired up to 80# with load on trailer but they hauled heavy loads before with no problems . Never needed to check empty always looked good unloaded and way low and couldent tell till trailer was loaded then I checked .

 

[H20Rat]

Re: Trailer Tire PSI?

There is no downside that I know of to running the tires at max rated pressure. That is what I would do.

Rougher ride and increased wear to the center of the tire. I've always used 50% capacity as a general rule. If the weight of the trailer + load is over 50% capacity of the tire, run full air pressure. If its below, then adjust downward some depending on feel of the trailer.

(my example, i've got a 4x8 lightweight trailer that i usually use for lawn clippings/misc lowes runs. In other words, WELL below the rated capacity of 1000# per tire. Those tires are rated at 60 psi cold for max weight, i'll run 45 to 50. The trailer handles far better behind the vehicle, with 60 psi it will actually bounce enough on rough roads it won't even stay behind the vehicle.)

 

[180shabah]

Re: Trailer Tire PSI?

I say 70#s cuz that give you a little leeway when your tire gets warm and pressure goes up because of it.

Leeway for what - Tires are rated for a given load at a given pressure, already accounting to the small increase in pressure when warm.

You need the 80 PSI or the tires will run hot and fail. At 55 PSi too much sidewall flex = heat.

Depends on how much weight he is carrying - per tire

 

[linxlvr]

Re: Trailer Tire PSI?

I would run the sidewall pressure. If you see you are wearing the center of the tire, feel free to knock the pressure down a small amount. I would even feel comfortable if it was my tire and I had the center of the tire wearing slowly compared to the rest of the tire to increasing COLD press. slightly over rating. It is a cold rating. If you go over 5# cold or under 5# it will change little. Under inflation will of course make a softer ride. But that is not the job of the tire, it is the job of the suspension. If you wanted to drop a 90# tire down to 85# I'd just say whatever. That sidewall rating is telling you essentially what the load rating of the tire is at the recommended pressure period. It is NOT telling you how much press to put in the tire IF you want to run the max load. If I were to radically change the tire press purposely I would get an OK from the manufacturer FIRST and then use a pyrometer to check both sides of tread and center of each tire and balance for good road face temps after a long towing session. Way over the top you say. It's how they come up with their info. I couldn't be bothered reinventing the wheel (couldn't resist) over tire press, so I just use the sidewall recommendation.
--
dw

 

[paultjohnson]

Re: Trailer Tire PSI?

Hmmmmm............ Some good points on here. AND it got me to thinkn' [I know, scary] Maybe it would work to do what some people do with car/truck tires to determine proper PSI . Put whatever PSI you feel comfortable with. Then take a piece of chalk, Ive heard some people use a piece of masking tape, Put the piece of tape, or draw a even chalkline from edge to edge. [sidewall to sidewall right across the tread] Then go drive a few miles and examine the tape or chalk.. . If its more worn out in the center of the tire, you are overinflated and the tire is bulging a bit in the center... If the edges are more worn, you are underinflated and the tire is cupped a bit in the middle. Of course you are looking for even wear. This process is used more with people that run oversize tires on trucks etc. But may work here. Either way I myself will run as high as PSI as i can get away with. Feels more stable to me and less rolling resistance means better mileage. Sway is just wasted energy in side to side motion. I M H O

 

[bigdee]

Re: Trailer Tire PSI?

If it is RECOMMENDED to run 80 why would anyone want to run less. Someone mentioned flex for a softer ride....flex will destroy a trailer tire. If it a softer ride you want then run car tires or softer springs! I learned the hard way that it is best to follow instructions and not try to second guess the manufacturer.

 

[Silvertip]

Re: Trailer Tire PSI?

Saw an EMPTY flat bed trailer with not one but two flat tires on the side of the freeway this past Wednesday. Tow vehicle was gone -- apparently to get two new wheels and tires. You guess is as good as mine as to what happened but my guess is too low a pressure and too high a speed.

 

[H20Rat]

Re: Trailer Tire PSI?

If it is RECOMMENDED to run 80 why would anyone want to run less. Someone mentioned flex for a softer ride....flex will destroy a trailer tire. If it a softer ride you want then run car tires or softer springs! I learned the hard way that it is best to follow instructions and not try to second guess the manufacturer.

think your logic through for a second... Yes i agree, flex kills tires by generating heat. But... The amount of flex depends on the load. Lets say your tire is rated at 1000# at 80 psi. If it is only carrying 250# and you drop the pressure to 50 psi, the amount of sidewell flex is still going to be LESS than that tire fully loaded at 80 psi. Idealy, you are maintaining the exact same contact patch in either case, which also means by default your sidewall has the exact same deflection.

Softer springs and/or car tires is not always an option. See my example above about the 4x8 trailer, that has a total weight of between 250 pounds to 2000#. It needs to be able to accomodate any weight in that range, and I adjust the tires to maintain proper ride and contact patch.

At least in theory, if you use a method like paultjohnson's above, your trailer tires will outlast those at max psi all the time, at least if you have a trailer like mine that has varied loads. Boat trailers aren't so variable and will generally always have near the max rated load.

 

[elkhunter338]

Re: Trailer Tire PSI?

Ok I have some experience with 5.3x12 tires. I had a tandem axle with these on it. Yes 1050 @ 80 psi is what they said on the sidewall. However I ran mine at around 65 psi with 4100 lbs on 4 tires, so 1025 per tire. I still had problems with the tires wearing the centers out, signs of over inflation.
I talked to a tire guy where I bought 2 new tires last summer because I hit a pot hole and broke the cords in both tires. Also blew a bearing buddy off when I hit the pot hole. Took a few hundred miles to show up. I explained my inflation pressure of 65 psi and how much load I had on the tires and how they still wore the centers. His comments where adjust the pressure so the tread wears flat, a small tire with high pressure is more apt to get damage when hits a pot hole. I never had one tire failure due to under inflation at 65 psi @ full load. Just my experience. I pulled this trailer probably 5,000 miles in the past 5 years. I sometimes pushed them up to 70 psi and I believe went as low as 60 psi, tried to keep them at 65 most of the time. I pulled them up the freeway one day at about 90 deg F and 60 mph.
Because my tires where at max load, and I ruined 2 tires last year hitting a pot hole, and my axles where 2,000 lbs and rusty I just got ride of them this winter. Replaced both axles with 3500 lb, with 15inch tires, and added disc brakes on one axle.

 

[linxlvr]

Re: Trailer Tire PSI?

Here is a new twist....
http://www.tire-information-world.com/goodyear-trailer-tires.html
--
dw

 

[paultjohnson]

Re: Trailer Tire PSI?

Here is a new twist....
http://www.tire-information-world.com/goodyear-trailer-tires.html
--
dw

interesting.....

 

[bigdee]

Re: Trailer Tire PSI?

think your logic through for a second... Yes i agree, flex kills tires by generating heat. But... The amount of flex depends on the load. Lets say your tire is rated at 1000# at 80 psi. If it is only carrying 250# and you drop the pressure to 50 psi, the amount of sidewell flex is still going to be LESS than that tire fully loaded at 80 psi. Idealy, you are maintaining the exact same contact patch in either case, which also means by default your sidewall has the exact same deflection.

Softer springs and/or car tires is not always an option. See my example above about the 4x8 trailer, that has a total weight of between 250 pounds to 2000#. It needs to be able to accomodate any weight in that range, and I adjust the tires to maintain proper ride and contact patch.

At least in theory, if you use a method like paultjohnson's above, your trailer tires will outlast those at max psi all the time, at least if you have a trailer like mine that has varied loads. Boat trailers aren't so variable and will generally always have near the max rated load.

After thinking a bit I have to agree that what your saying makes sense. I have a utility trailer with 4.80x12 @ 60psi that has varying loads hauled on it but I always inflate to the max because it is too much of a hassle to be constantly adjusting pressures so I figure that keeping them at the max pressure is the failsafe way to go.

 

[uplander]

Re: Trailer Tire PSI?

http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

http://www.maxxis.com/Repository/Files/m8008load.pdf

 

[elkhunter338]

Re: Trailer Tire PSI?

I forgot I reused my 5.3x12 tires and axles this winter to make a boat trailer for my 14' klamath. I plan to run tire psi at 35 psi to start with and adjust from there up or down based on tire wear.
might even run 30 psi if the tires do not look under inflated.