Help !! Landmark 365 Tire Pressures ??

["Hi-Viz" Bill]

I would like to tap into the vast knowledge base here .. My new GMC "finally" arrived .. So, now it's time to pull my NEW LM 365 Newport .. The Goodyear "H" rated tires have +- 100# to 105# of air, but the sidewalls say 125 psi "cold" ... Before I pull this rig, should I increase all the pressures to the 125# status and maintain it there??? The coach is not loaded down yet with "over winter" retire in FL quantity of things, but will be in January. Any wisdom on this subject, would be GREATLY appreciated !!

 

[Bob&Patty]

Yes, fill them to 125# as the tire said. Also fill the tires on your truck to the max cold reading.

 

[Jim.Allison]

I have Goodyear G114s, I use an goodyear load inflation table to determine the pressure for the tire, I keep them at 95 PSI as that is more than enough to support the rig. I printed a copy of the inflation table and taped it to my basement door for reference. Remember part of the load on a fiver is on the pin and not your trailer tires, weighing the rig will give you critical information and also allow you to properly inflate your tires according to the load they are carrying. Look up the model of tire that you have find the inflation pressure chart, and inflate them accordingly. This information is available on the net. I don't know what tire you have or I would look it up for you. But you can get into the ball park on the load your tires carry by taking the GVWR and subtract 15% and divide by the number of tires on your rig. That will be the approximate load your tires see. Then refer to the load inflation chart for your GY H rated tire and find that load, and inflate accordingly for max service on your tires.

BTW, with my tires inflated properly all I have to do is check them, I do not have to worry about increases in inflation due to ambient temps, seasons, or altitude. I have one inflation pressure for all seasons 95 PSI cold and I'm good to go; winter, spring, summer, fall.

I would like to tap into the vast knowledge base here .. My new GMC "finally" arrived .. So, now it's time to pull my NEW LM 365 Newport .. The Goodyear "H" rated tires have +- 100# to 105# of air, but the sidewalls say 125 psi "cold" ... Before I pull this rig, should I increase all the pressures to the 125# status and maintain it there??? The coach is not loaded down yet with "over winter" retire in FL quantity of things, but will be in January. Any wisdom on this subject, would be GREATLY appreciated !!

 

[porthole]

Yes, fill them to 125# as the tire said. Also fill the tires on your truck to the max cold reading.

Do not blindly fill them to 125 psi.

Goodyear has detailed information on proper load and inflation pressures.

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

https://www.goodyeartrucktires.com/pdf/resources/publications/2010_loadinflation.pdf

 

[ksucats]

A lot of different opinions and here is mine - the best way is to get individual wheel weights with the coach loaded as you would have it loaded for a trip (Propane, water, food, clothing, dogs toys ( :angel: ), everything. Then, using those individual wheel loads, go to the respective tire manufacturers web site and get the proper cold inflation pressure for that load. Now the question - how many of us actually have done that - I don't have the answer but I'd guess not a large percentage of those out there pulling trailers. So, in light of that, most of us will fill them to the max (mine are also 125) because we ( I ) don't really know what each individual wheel is carrying. On my KeyWest the entire kitchen with Residential refer, stacked washer/dryer, and entertainment center, not to mention bathroom, are all on the off-door side. I would imagine that that side is quite a bit heavier than the door side which only carries the dinette, theater seating and, thinking about it, the bedroom dresser and drawers. On the Cedar Creek that we traded in, same basic floor plan, our off-door side tires carried well over 1000 lbs more weight than the door side.

Then, add the fact that you may not be perfectly level and you add additional weight to the front or rear tires depending on which is lower. So, long reply but the best is to get the individual wheel load weight and go from there. Lacking that I personally take mine to the max as shown on the tire side wall (125 psi for my 17.5 H rated Goodyears.) As for the truck, when loaded I go with the pressure recommended by Ford; when empty I've taken the backs down some to try to reduce the harshness of the ride. It is a royal PITA though when getting ready to hook up again as I have to air up those duals.

By the way, congrats on the truck - as I recall you've been waiting a good while for it to show up. Time to get it, and the coach, out and enjoy.

 

[danemayer]

You don't want them either under inflated, or over inflated, as either condition can cause problems. As noted earlier, if you get individual wheel weights (offered at some rallies, and at some Escapees locations), you'll be able to judge based on those weights and the Goodyear inflation tables.

Absent individual wheel weights, I'd suggest you start with the GVWR of the trailer, subtract out 20% of that as being on the pin. So that would be 18,000 - 3,600 = 14,400 on the wheels. Divide by 4 and you have approximately 3,600 on each wheel.

I would allow for uneven weight distribution by assuming one side, or one wheel could be carrying 400 lbs more weight. So let's assume 4,000 lbs on at least one of your wheels.

Add a few hundred pounds of safety margin and that would take you to 4,300 lbs. The Goodyear inflation table shows the 215/17.5 tire as carrying 4,340 lbs at 110 psi.

I would think 110 psi would be a safe inflation setting on your tires.

On our coach, the GVWR is 16,000 and we have about 3,600 on the pin. That puts about 3,100 on each wheel. I've had individual wheel weights done twice at Heartland North American Rallies. The results were quite different due to the changes in what we were carrying and where it was stored. So I inflate the G114s to about 105 psi, which supports 4,180 lbs. That gives me a safety margin of about 500 lbs on the heaviest wheel - and does so even if DW moves things around changing the weight distribution.

 

[TxCowboy]

You don't want them either under inflated, or over inflated, as either condition can cause problems. As noted earlier, if you get individual wheel weights (offered at some rallies, and at some Escapees locations), you'll be able to judge based on those weights and the Goodyear inflation tables.

Absent individual wheel weights, I'd suggest you start with the GVWR of the trailer, subtract out 20% of that as being on the pin. So that would be 18,000 - 3,600 = 14,400 on the wheels. Divide by 4 and you have approximately 3,600 on each wheel.

I would allow for uneven weight distribution by assuming one side, or one wheel could be carrying 400 lbs more weight. So let's assume 4,000 lbs on at least one of your wheels.

Add a few hundred pounds of safety margin and that would take you to 4,300 lbs. The Goodyear inflation table shows the 215/17.5 tire as carrying 4,340 lbs at 110 psi.

I would think 110 psi would be a safe inflation setting on your tires.

On our coach, the GVWR is 16,000 and we have about 3,600 on the pin. That puts about 3,100 on each wheel. I've had individual wheel weights done twice at Heartland North American Rallies. The results were quite different due to the changes in what we were carrying and where it was stored. So I inflate the G114s to about 105 psi, which supports 4,180 lbs. That gives me a safety margin of about 500 lbs on the heaviest wheel - and does so even if DW moves things around changing the weight distribution.

Dan, thanks for your post. Lots and lots of us do not have access to weigh stations, particularly those that can give you individual wheel weights. We need something else as a guide for tire pressure and your post does that.

 

[chrizg]

I run trailer tires at max psi. When I was in Elkhart, I stopped by Treddit as I was going to get some new tires for the prev big country, and they said that if you have a blowout and wanted to claim warranty, they would deny the claim if you ran them anything other than max psi cold.

Car/truck tires are different will bald in the middle of the tire if you run them at max PSI unless you have the weight on the tire that supports the higher PSI.

 

[jmgratz]

I always run my tires at the cold inflation stated on the tire sidewall. If you don't weigh yours then presume you are max on the tires to be safe. One of the fastest ways to cause damage to your tire is to run it under-inflated. If you want a ballpark figure go to the Pilot Truck Stop and weigh the tow vehicle without the trailer. Then weigh it with the trailer. Then you can weigh just the trailer. Then you can subtract the truck weight from the trailer weight to figure your pin weight. Then subtract the pin weight from the trailer weight and you will have the weight you are carrying on the axles. Or you can go to the Escapee Rainbow Park in Livingston TX and they will weigh the truck and RV by each tire. Some rallies do that too.

 

[porthole]

I run trailer tires at max psi. When I was in Elkhart, I stopped by Treddit as I was going to get some new tires for the prev big country, and they said that if you have a blowout and wanted to claim warranty, they would deny the claim if you ran them anything other than max psi cold.

What does tire pressure have to do with blowmax warranty or longevity?

I would challenge any tire jockey to prove I didn't run my tires at the proper inflation, just can't do it.


Back to the original posters questions.

Since he has Goodyear G-114's he is in a different category. He has quality tires (great tires, but not perfect though, like anything else), excellent load capacity and a manufacturer that will support him for defects.
And since the Goodyear G-114's should be inflated per the recommended Goodyear tire inflation chart, the 125 PSI cold is a Maximum pressure that you should use, not a daily recommended travel pressure.

Running the G-114's at 125 psi cold will give you 19,000 (4800 per wheel) pounds of capacity. AFAIK there are no 2 axle 5th wheels carrying that much weight on two axles.

But, if you want to run them at 125 psi and have the increased pressure and decreased ride quality, go for it.

Dan's recommended cold inflation of 110 psi for a starting point, sans weighing the rig is a good number to go by.

And if you are running a TPMS, expect to see pressures build to 140+ in hot weather starting at 110 cold.

 

[hoefler]

When I switched to 17.5" tires and wheels, I ran the presure suggested with the load chart from the tire manufacture. My first trip out, about 200 miles, I noticed my fuel economy was down 1.5 mpg for the trip. I have done this trip several times, and know what was expected. On the trip home, when stoping for fuel, I shot the tires with my temp gun and found the tires 20*-25* hotter than the tires on the truck. They always have been the same or a bit cooler. I aired them up to the 125 psi as stated on the side wall. My milaege came back up and now they run cooler than the truck by 10*-15*.