My car and trailer weigh about 4500 lbs. The trailer has ST205/75 D 14 tires. Max pressure says 50psi.
What's a good psi, and how is it determined?
What's a good psi, and how is it determined?
Trailer Tire Pressure
- Thread starter SpeedThrills
- Start date
-
Ddaddy
Just doing what I do
Trailer tires should always be inflated to the maximum psi indicated on the tire sidewall. This is because trailer tires are built with a thicker sidewall than passenger vehicle tires to handle more vertical load. If under inflated the thicker sidewall generates excessive heat and can lead to failure.
sireland67
Well-Known Member
But inflated to max pressure will cause a trailer to sway, I have found if you stay around 35 psi it will handle nice.
I also do not pull a trailer over 100 miles at a time, so heat may not be causing me any issues.
I also do not pull a trailer over 100 miles at a time, so heat may not be causing me any issues.
Ddaddy has it right, but an empty trailer will ride hard.
The max load at 50 psi could be 4500 lbs for example.
So divided by 4 tires you could haul it at 12.5 psi and be good.
Thats the theory, i run mine at 40.
50 if i max out the trailer.
So on a car, its very different, 35 psi in tires on your average pickup, if you switch out tires with more plies and a higher load rating you could in theory run a lower pressure.
So many run the tires a max pressure, if underloaded the centre of the tread wears prematurely.
The max load at 50 psi could be 4500 lbs for example.
So divided by 4 tires you could haul it at 12.5 psi and be good.
Thats the theory, i run mine at 40.
50 if i max out the trailer.
So on a car, its very different, 35 psi in tires on your average pickup, if you switch out tires with more plies and a higher load rating you could in theory run a lower pressure.
So many run the tires a max pressure, if underloaded the centre of the tread wears prematurely.
sireland67
Well-Known Member
I can tell you for a fact, I went and had new tires put on our camper, and the tire shop put them at max inflation.
You could not hold that trailer on the road, it swayed so bad, my wife was behind me and said what is wrong with trailer.
It was white knuckle driving for a few mile until I pulled over and let some air out of the tires.
You could not hold that trailer on the road, it swayed so bad, my wife was behind me and said what is wrong with trailer.
It was white knuckle driving for a few mile until I pulled over and let some air out of the tires.
Tail wagging the dog. Many trailer owners manuals have reccomended tire pressure.some are on a decal right above the wheel as well as wheel nut torque. But that makes it too easy.
sireland67
Well-Known Member
So true, none of the ones I have say max pressure.
Ddaddy
Just doing what I do
A lot of it depends on the tire. True trailer tires should be run at max inflation when loaded. Often times, passenger vehicle tires are used on some trailers and the rules become different. You are also talking about a camper rather than a car trailer so your application adds to the equation.
However, the OP posted a specific tire on a car trailer and they are recommended to be run at max inflation as listed on the sidewall.
sireland67
Well-Known Member
The camper is as heavy as his load, and they were trailer tires.
I can see cheap car tires needing more inflation.
I also run 35 psi in my car trailer, with a full sized E-Body runs around 6500 lbs.
All have trailer tires, the over-inflation caused me an issue.
The best advice to the op is to inflate to max, it is easy to pull over on the side of the road and adjust the pressure to what makes your tow vehicle happy.
I can see cheap car tires needing more inflation.
I also run 35 psi in my car trailer, with a full sized E-Body runs around 6500 lbs.
All have trailer tires, the over-inflation caused me an issue.
The best advice to the op is to inflate to max, it is easy to pull over on the side of the road and adjust the pressure to what makes your tow vehicle happy.
JDMopar
Well-Known Member
My car trailer has the same size tires, and I just put 4 new wheels and tires on it. I always run 50 lbs. in mine, and never have had any problems. I typically carry my wifes Saturn Vue on my trailer, to or from the beach if she and I are going to, or coming from the beach at the same time. Car and trailer weigh around 5700 lbs, and my trailer tires never sway or get hot....and I usually run 75 mph. I just bought some tire covers that Camping World had on sale, so hopefully the sidewalls won't dry rot like my old tires.
Last edited:
I run my pressure according to load. If I max out my 18' trailer with two 7000lb axles I'll put the 60psi in the my tires say is "max" pressure. But if I'm doing light hauling I'll run as low as 45psi. My trailer is a 2003, I've had it since new, it has thousands of kms on it. And I have never had a failure of any sort, tires or suspension. Think about the "max" word. I also have never ran the 70psi my 3/4 ton duramax calls for either. I don't like riding on Fred flintsone wheels. I've hauled everything from cars to tractors. Works for me.
Side note: on my 5th wheel camper, which is very heavy, I run max. It reduces the soft sway around effect.
Side note: on my 5th wheel camper, which is very heavy, I run max. It reduces the soft sway around effect.
I just did what I guess I should've done in the first place. I know there's lots of experience and know-how on FABO, but I just called the mfg. of the trailer, Dively, and asked the man who answered how much air.
He said 50 psi because they're 6 ply tires.
I test drove it yesterday, with 35 psi, and it would get swaying a bit with a little jiggle of the steering wheel.
I'll go to 50 and see how it is. I already moved the car up about 3", so it won't be conclusive, but I'll see how it goes. Next "test" will be Friday, when I take my Mustang (There, I said it!) to Atco. My Duster is a couple years away from being ready for that.
Thanks for all the replies and ideas. Got me to thinking...
He said 50 psi because they're 6 ply tires.
I test drove it yesterday, with 35 psi, and it would get swaying a bit with a little jiggle of the steering wheel.
I'll go to 50 and see how it is. I already moved the car up about 3", so it won't be conclusive, but I'll see how it goes. Next "test" will be Friday, when I take my Mustang (There, I said it!) to Atco. My Duster is a couple years away from being ready for that.
Thanks for all the replies and ideas. Got me to thinking...
nm9stheham
Well-Known Member
I ran the OP's tires for some time and ran them around the low-mid 40's on an enclosed trailer. Ran fine, never got too hot.
BTW, most of the bias ply trailer tires that size are kinda junky.....OK if for short distances like back and forth to Englishtown. I switched to radial trailer tires for our long hauls (500 miles typical each way) and the tire life went up about 4-5 fold. Stability did not change.
And yes, OP, car loading position has a lot to do with stability. Then any looseness of the hitch in the receiver needs to be eliminated; you'd be surprised how that can effect things. Finally, the towing vehicle is important, some have a lot of sideways give in things like standard leaf springs, and a short wheelbase vehicle will swing back and forth more easily.
A lot of tongue weight from the trailer lifting the towing vehicle's front end is always a source of directional instability. So moving the car forward can help (move the car's CoG up closer to the hitch) but can hurt (excess tongue weight lifting the front of the towing vehicle).
Share you towing vehicle and trailer info if you like.
BTW, most of the bias ply trailer tires that size are kinda junky.....OK if for short distances like back and forth to Englishtown. I switched to radial trailer tires for our long hauls (500 miles typical each way) and the tire life went up about 4-5 fold. Stability did not change.
And yes, OP, car loading position has a lot to do with stability. Then any looseness of the hitch in the receiver needs to be eliminated; you'd be surprised how that can effect things. Finally, the towing vehicle is important, some have a lot of sideways give in things like standard leaf springs, and a short wheelbase vehicle will swing back and forth more easily.
A lot of tongue weight from the trailer lifting the towing vehicle's front end is always a source of directional instability. So moving the car forward can help (move the car's CoG up closer to the hitch) but can hurt (excess tongue weight lifting the front of the towing vehicle).
Share you towing vehicle and trailer info if you like.
10 psi per ply. for trailer tires. I have pulled countless trailers, some grossly overloaded. If you want best service, minimal blowouts, 10 psi per ply and don't speed! Over 60 MPH with trailer tires is speeding. But why listen to me.......
famous bob
mopar misfit
I`ve always tried to run 75 to a 100 pounds tongue weight on car trailers (open type), and 50 to 70- on a long ATV trailer. And a short wheel base p/u will be a lot easier to back than a long 4 door or quadcab, but won`t handle the weight as good. I only live about 9 miles from our dragstrip, so a short bed standard cab is better for me.10 psi per ply. for trailer tires. I have pulled countless trailers, some grossly overloaded. If you want best service, minimal blowouts, 10 psi per ply and don't speed! Over 60 MPH with trailer tires is speeding. But why listen to me.......
GeorgeH
Well-Known Member
Standard valve stems don't like 50 psi which are pretty common in a 14" trailer wheel assembly. Have lost more tires from valve stems failing then from a little bit of under or over inflation even running at less psi.
Last edited:
nm9stheham
Well-Known Member
FWIW.... I almost agree with that for the cheaper bias ply trailer tires. But running newer radial trailer tires, we run 70-80 for 500 miles at a crack and never a single tire problem in almost a quarter of a million miles in the last 11-12 years.10 psi per ply. for trailer tires. I have pulled countless trailers, some grossly overloaded. If you want best service, minimal blowouts, 10 psi per ply and don't speed! Over 60 MPH with trailer tires is speeding. But why listen to me.......
Now small wheel bearings are another matter! Just picked up a new work trailer today with a step heavier axles (5200# axles) so we can hopefully stop burning out the smaller wheel bearings 1x-2x per year. Towing about 6000 lbs gross average (I think).
abodyjoe
Well-Known Member
we just bought a travel trailer.. all the research i did said ya run the max cold psi on the sidewall of the tire. they said the same thing with my little 5x8 trailer.
towed that 3800 pound travel trailer home 700 miles at max psi according to the sidewall and it towed very nice. hit speed as high as 75mph but kept it between 60-70 most of the time..
towed that 3800 pound travel trailer home 700 miles at max psi according to the sidewall and it towed very nice. hit speed as high as 75mph but kept it between 60-70 most of the time..
-The tire says max 50, so I stopped there.10 psi per ply. for trailer tires. I have pulled countless trailers, some grossly overloaded. If you want best service, minimal blowouts, 10 psi per ply and don't speed! Over 60 MPH with trailer tires is speeding. But why listen to me.......
-I'd say in most areas now, 60 mph is clogging the road.
In my research over the summer, I read that LT tires are for just that, light trucks. I wish I could remember the details, but it makes sense. If I somehow wreck, I don't want the insurance companies seeing LT's on it.
The trailer mfg. installed the valve stems. They look standard to me. The trailer mfg. also recommends 50 psi. I hope you're wrong! What would be a good alternative?
I went to Atco last night. 80 miles each way. There is still a feeling that it will sway excessively if I don't pay attention. It rode well other than that.
I will only use this trailer for shorter jaunts, such as an Atco trip.
Part of the swaying thing is probably the truck. It's a 95 F150, w/ 300 straight 6. 5 spd and 2.73 gears. I dont think the suspension is stiff enough.
The trans has a 3.92 1st gear to help that 2.73. But I think a set of 3.27's would be nice. It doesn't like grades at all.
I will only use this trailer for shorter jaunts, such as an Atco trip.
Part of the swaying thing is probably the truck. It's a 95 F150, w/ 300 straight 6. 5 spd and 2.73 gears. I dont think the suspension is stiff enough.
The trans has a 3.92 1st gear to help that 2.73. But I think a set of 3.27's would be nice. It doesn't like grades at all.
abodyjoe
Well-Known Member
Towing speed limits range from 55-65 mph depending on state.
http://onlinetowingguide.com/pdfs/StateTowingLaws.pdf
http://onlinetowingguide.com/pdfs/StateTowingLaws.pdf
-
Similar threads
