Tire pressure

[JOFO17]

I have wondered about this for a while now. If the tires on my trailer say something like. "max load 2500 lbs. Max pressure 55 psi" Should I inflate to 55 psi or is that just the MAX that they should be inflated to?

 

[Sprig]

Run your trailer tires at the max pressure, in this case 55 lbs. Trailer tires are different from car tires and are designed to be inflated to the max. Probably the number one cause of trailer tire fail is under inflation. Under inflation causes the trailer tires to heat. This often causes failure/blow out. You should probably check the pressure every 60 days or so.
Another thing to check is the speed rating on your trailer tires. Most , not all are rated for 60mph. Towing above the max speed rating also causes the tires to heat up and fail.
Finally trailer tires are greatly affected by environmental factors and UV rays. If you see cracks in the sidewalls, especially around the area where the tire meets the wheel the tires should probably be replaced.

 

[robert graham]

Best to run about 5psi less than that max number on the sidewall.....from experience I know about this. If you start at the max then when tire heats up on the highway it'll gain several pounds of pressure, causing over inflation...

 

[robert graham]

Best to run about 5psi less than that max number on the sidewall.....from experience I know about this. If you start at the max then when tire heats up on the highway it'll gain several pounds of pressure, causing over inflation...

 

[ahicks]

Best to run about 5psi less than that max number on the sidewall.....from experience I know about this. If you start at the max then when tire heats up on the highway it'll gain several pounds of pressure, causing over inflation...

Old wives tale.

 

[matt167]

you can inflate them according to the load charts for the tire, or just put them at max pressure and not worry about it..

The max tire pressure is listed cold for a reason. The temperature inflation is factored into that pressure specification

 

[H20Rat]

Run your trailer tires at the max pressure, in this case 55 lbs. Trailer tires are different from car tires and are designed to be inflated to the max.

No, well, sort of no. Best to follow the manufacturers recommendations...

The max PSI is for the maximum load ONLY. If you have less than max, especially if it is significantly less, you don't want to run at max PSI. It puts the tire outside of its operating envelope, and will cause it to wear prematurely as well as have less traction. Ideally, you can find a tire load chart that shows exactly what the PSI should be for your specific tire and load combination.

As an example, here is the load chart for Maxxis trailer tires. The ST205/75R15 has a max load of 2150 pounds at 65 psi. It is rated all the way down to 1220 pounds, at 25 psi. Those values aren't random, they are designed so the tire will have the exact same sidewall deflection and footprint on the pavement across the entire load range.

https://www.maxxis.com/trailer/trail...nflation-chart

 

[matt167]

No, well, sort of no. Best to follow the manufacturers recommendations...

The max PSI is for the maximum load ONLY. If you have less than max, especially if it is significantly less, you don't want to run at max PSI. It puts the tire outside of its operating envelope, and will cause it to wear prematurely as well as have less traction. Ideally, you can find a tire load chart that shows exactly what the PSI should be for your specific tire and load combination.

As an example, here is the load chart for Maxxis trailer tires. The ST205/75R15 has a max load of 2150 pounds at 65 psi. It is rated all the way down to 1220 pounds, at 25 psi. Those values aren't random, they are designed so the tire will have the exact same sidewall deflection and footprint on the pavement across the entire load range.

https://www.maxxis.com/trailer/trail...nflation-chart

Yes and no.. Trailer tires are generally hot garbage, with a couple of exclusions.. Running a trailer tire with more air than what is really required causes them to actually run colder due to less rolling resistance and thus a higher sustainable speed. and trailer tire failures are almost always sparked by an overheat condition.. low pressure, too fast. Bang.. I Sell/ install lots of trailer tires, and the other 3 are almost always low on pressure if they have suffered a blowout

 

[Silvertip]

Inflating trailer tires to whatever pressure is recommended for the load you carry is fine -- EXCEPT a problem arises when the next trip you take has the boat more heavily loaded that what you aired the tires for. You now have an under inflation issue. So unless you religiously check tire pressures for the load you are carrying, you are best airing them up to the max indicated on the sidewall.

 

[jimmbo]

Some Trailer Tires, like the Goodyear Endurance have Max Pressures of 65(load range D) or 80 psi(load range E) so if you are running these in place of load range C tires, you don't have to inflate them to max.

 

[matt167]

All trailer tires are categorized by the load range according to the plies they have.. I think all manufactures make C-E and a couple make LRF and even LRG in 235/85/16
G=14 ply
F= 12 ply
E=10 ply
D=8 ply
C=6 ply

You still need to verify the inflation pressure according to a chart to have the tire at any amount under it's max inflation. At my shop for instance, we don't carry 205/75/15 LRD this time of year, because we consolidated the trailer tires for the snow tires.. In actuality the LRD is only cheaper by a couple dollars and makes no sense to stock both

 

[bigdee]

Inflate to max pressure and be worry free. It is AIR PRESSURE that determines the integrity of the tire. There is no advantage to running less than max. Lower pressure means lower load capacity why would you do that.

 

[ahicks]

Inflate to max pressure and be worry free. It is AIR PRESSURE that determines the integrity of the tire. There is no advantage to running less than max. Lower pressure means lower load capacity why would you do that.

The advantage to running less than max air pressure is that the trailer won't rattle itself, and the tow vehicle it's attached to, apart.

Max load capacity air pressure often not necessary if the load isn't maxed. Running max rated air pressure makes the call regarding how much air pressure brain dead simple. If that's your tendency go for it.

Options are to use a chart to find load and pressure. Best plan, in my little world, is to check the tire sidewalls and the wheel bearings for excess temp. with your hand after traveling a short distance, then at fuel stops and potty breaks for the rest of the trip.

 

[CNT]

You know... as for car/trucks, generally, it's 32psi. I almost always inflate MY vehicles to 35psi. In doing so, I notice auto tires tend to wear uneven or sometimes even wear faster at 32psi. Maybe can't compare with a VW, but years ago, I bought a nice 90,000 miles VW Jetta GL (love that stick), and bought all 4 new tires right away. On those tires (some foreign brand), the wall says somewhere 55psi, so I inflate it (and maintain) to the MAX, drove it to 160,000 miles and the tires were still like new.

Now, concerning trailer tires, interesting concept. Looks like I might do a 32psi and leave it like that. Makes sense that trailers would bounce or swing if it's hard (high inflated). When I buy my boat/trailer, I will do some experiment. As one said in here, bearings play a huge role in trailer tires.

 

[matt167]

You know... as for car/trucks, generally, it's 32psi. I almost always inflate MY vehicles to 35psi. In doing so, I notice auto tires tend to wear uneven or sometimes even wear faster at 32psi. Maybe can't compare with a VW, but years ago, I bought a nice 90,000 miles VW Jetta GL (love that stick), and bought all 4 new tires right away. On those tires (some foreign brand), the wall says somewhere 55psi, so I inflate it (and maintain) to the MAX, drove it to 160,000 miles and the tires were still like new.

Now, concerning trailer tires, interesting concept. Looks like I might do a 32psi and leave it like that. Makes sense that trailers would bounce or swing if it's hard (high inflated). When I buy my boat/trailer, I will do some experiment. As one said in here, bearings play a huge role in trailer tires.

No, it's not.. Cars, trucks, and even modern trailers actually have listed air pressures that apply to their OEM tire load range/ speed ratings ( not just the OEM tire as some suggest ).. Usually on the data plaque on a trailer, and LF door jam/ door of a car ( trunk on some older GM's ).. on a car/ truck it has more to do with traction and stability and it's almost never 32 psi... The only thing that is pretty much rock solid on air pressure is half ton trucks generally take 35 PSI except some newer Rams which spec 39 psi and Toyota's

For a trailer tire, never run it 'soft'. you'll heat it up and tear apart the sidewalls due to under inflation and cause a blowout that will happen later.

 

[matt167]

Options are to use a chart to find load and pressure. Best plan, in my little world, is to check the tire sidewalls and the wheel bearings for excess temp. with your hand after traveling a short distance, then at fuel stops and potty breaks for the rest of the trip.

run them soft enough you notice them hot, and you have destroyed the tire. under inflation is what destroys tires.

 

[ahicks]

I couldn't agree more, but they get REALLY hot before they go. That condition EASILY detected AND avoided by taking their temp with your hand. If you have one, a tire or a bearing, getting warm on you, generally you have time to get the problem taken care of early enough to head off a problem.

20 years experience as a service manager at a large RV dealership, with over 50 years towing all over the country without a single failure. I do have a clue regarding what I'm talking about....

 

[matt167]

Yes, but not everyone might know how hot, is too hot.. Every RV ( not motorhome ) that I have put tires on, has had at least one blowout and suffered damaged wheel wells/ fiberglass. Almost always, all the tires are under inflated and none of them are very old.. I think if you run them softer than the max pressure without the load chart, you need to have an understanding of what is what.. It's not a bad suggestion all in all, but it's safer to run them at a higher pressure if your unsure. probably really don't need max pressure depending on the load rating, unless it's a trailer able yacht or something huge. but 80% or so of that max number I would call a safe minimum, but that is variable depending on load range.

 

[bigdee]

The advantage to running less than max air pressure is that the trailer won't rattle itself, and the tow vehicle it's attached to, apart.
.

The springs are there to soften the load....flexing the under-inflated TRAILER tires to soften the ride will cause tire to overheat. The only way to take the bounce out of a trailer is to install shocks, I don't carry passengers in my trailers so I could care less.

 

[ahicks]

Yes, but not everyone might know how hot, is too hot.. Every RV ( not motorhome ) that I have put tires on, has had at least one blowout and suffered damaged wheel wells/ fiberglass. Almost always, all the tires are under inflated and none of them are very old.. I think if you run them softer than the max pressure without the load chart, you need to have an understanding of what is what.. It's not a bad suggestion all in all, but it's safer to run them at a higher pressure if your unsure. probably really don't need max pressure depending on the load rating, unless it's a trailer able yacht or something huge. but 80% or so of that max number I would call a safe minimum, but that is variable depending on load range.

It's pretty easy to tell really. If you can leave your hand on the tire (or bearing) without too much discomfort, you're good to go. Once in a while, while traveling in the southern states especially, the side of the trailer and tow vehicle facing the sun will be running noticeably hotter than the shaded side. Normally this difference in temps is exactly what I am looking for when checking to make sure everything is OK. If you find a hot or very warm tire, you have a problem that needs to be addressed right away!

In the case of the sunny side tire scenario, they can get warm even when inflated to max! That's when a judgement call may need to be made....