Tire air pressure

[Turbo Terry]

My 2022 regular cab long box has done duty as a daily driver with 500 lbs gravel bags in the back in the winter for a better ride and traction on the snow and ice. The new Goodyear Wrangler Dura Tracs aired to 50 lbs front and 40 lbs rear have worked out real well. Summer time tires would go to 80 lbs front and rear to haul my 2900 lbs slide in truck camper. But last week my wife fell in love with a 24 ft travel travel so the truck camper is going away after 23 years Dry weight 6600 lbs and tongue weight 750 lbs Full load 10000 lbs so 10 percent 1000 lbs on the bumper. Maybe 600 lbs Honda Foreman in the back of the truck on some trips . 3500 is rated 1800 lbs at the bumper .
So let’s talk air pressure then . How much front and rear ? Then when I un hook someplace do I have to air tires down The ride will be pretty bad maybe??? Then air back up . How are you travel trailer haulers doing this?

 

[Diesel85]

The work truck I'll adjust air pressure accordingly to what is loaded by a slight amount. I found that unless I'm fully loaded to the kilt, 65-70 PSI works fine. I keep an eye on the pressures once driving for a while, especially when it's extremely hot out. Fully loaded, 70 PSI can quickly turn into 75+ PSI doing 65+ mph with the heat.

Part of being a good/responsible driver is keeping an eye on those tire pressures while towing heavy.

 

[Cummins12V98]

For the front and rear you need to know your LOADED tire weights. Once you know that use the tire weight inflation chart for your tire then add 5psi to rears and 10 psi to fronts. Using this method I get more mileage than most with even tread wear.

 

[petersonj]

Great advice from @Cummins12V98.

First, I would weigh your truck with what you normally carry. Weigh the axles independently. Write down the weights and keep them handy. I am assuming that you are going to use a weight distribution hitch.

It is worthwhile to purchase a tongue scale. Load you travel trailer with your gear. If you think you are near maximum capacity of the gross trailer weight, then check the tongue weight with your new scale - go for about 1,000 lbs - this will be close enough for now.



When you hook up the trailer, the rear of the truck will sag and the front of the truck will lift. Set the tension bars on the WDH to make things approximately level. Now, go weigh each truck axle and the tandem trailer axles. Write the numbers down.

If the new front axle weight is same as the empty front axle weight (+/- 50 lbs) you are good with the tension bars. Matching the new front axle weight with the empty front axle weight is important as this will make the steering effort and steering control feel normal. If the front axle is too heavy, the steering effort will be heavy and feel sluggish. If the front axle is too light, the steering effort will be too easy and feel touchy. Both situations will cause poor handling.

If the tongue weight is within 10% - 15% of the trailer weight, then the tongue weight is good. If the truck rear axle and tires, and the trailer rear axles and tires are at or under their respective weight limits, then you are good to go.

You can fine tune your tongue weight, WDH tension, and tire inflation to suit your self. It is not an exact science.

- John

 

[Turbo Terry]

All good info thanks

 

[petersonj]

But last week my wife fell in love with a 24 ft travel travel so the truck camper is going away after 23 years

My wife and I went from years of owning a side-in truck camper to a 5,200 GW travel trailer. For us, there were many pluses - eight tires on the road with brakes, low center of gravity with a wide stance, 100% of the truck bed available for cargo, trailer floor close to the ground, no climbing up to get into a bed,
and very easy to disconnect the trailer at a campground and use the truck without changing tire pressure.

Of course, there are down sides - like losing the ease of towing, and maneuvering with the additional combined length, but the pros outweighed the cons for us. Plus, it is SO easy to drive with the proper setup.

I think you will enjoy the changeover.

- John

 

[Turbo Terry]

At 75 it was becoming increasingly hard to get up into bed etc as you say. We had many adventures with the slide in but are really excited to be in the travel trailer . Time will tell

 

[Jim W]

In my humble opinion the front tires should be at the recommend air pressure on the "B" pillar placard of your truck. This should be regardless of towing or unloaded as the engine and the drive train have the most influence on the front axle loading numbers.

For the rear tires I would take the truck and trailer to a CAT scale. Weighting them both together and separately to find the actual loaded axle weights and combined Gross Vehicle weights. Using an air inflation table for the tires I would than use the appropriate air inflation number to support the rear axle tire loads.

This is what I have done for my truck since new, and I have never had an issue with the tires when loaded or truck handling issues.

Just my experience from towing three different 5ers and two pop-up campers.

 

[Turbo Terry]

Yes there’s a lot of weight on the front of theses trucks

 

[Cummins12V98]

I don't know much about the tire capacity on SRW trucks but 4wd, AISIN makes my DRW need the full 80psi. That is why I said you should weigh the front and rear axles. I am betting the SRW tires have a much higher weight rating than my DRW tires have. So based on that I would wager 80psi front is NOT needed unless maybe you have a camper that loads the front axle.

 

[AH64ID]

I don't know much about the tire capacity on SRW trucks but 4wd, AISIN makes my DRW need the full 80psi. That is why I said you should weigh the front and rear axles. I am betting the SRW tires have a much higher weight rating than my DRW tires have. So based on that I would wager 80psi front is NOT needed unless maybe you have a camper that loads the front axle.

OE sized DRW tires need 80 psi to support the FAWR, but SRW sizes only need 65 psi.

80 psi supports 1,260lbs more than the front axle is rated to carry.

I will run up to 65 psi when loaded up on my truck, but most the time 50-55 is all I need empty . The tires wear better and traction is better when not overinflated.

 

[johnmyster]

Your camper is not all that large or heavy on the tongue. Cold, 60 front, 60 rear sounds like a good starting point and is what the factory size tires would have been specified for a 2500, axle loads up to 6000 pounds front, 6000 pounds rear.

When unloaded the rear will be a little stiff. It's a compromise you'll have to make unless you have convenient compressed air on the truck/camper and want to constantly adjust.

I target 60f/65r cold. 2014 3500 megacab, 1650# tongue weight camper. Unloaded back axle is ~3250. ~6000 loaded. 275/70r18.

 

[Cummins2014]

OE sized DRW tires need 80 psi to support the FAWR, but SRW sizes only need 65 psi.

80 psi supports 1,260lbs more than the front axle is rated to carry.

I will run up to 65 psi when loaded up on my truck, but most the time 50-55 is all I need empty . The tires wear better and traction is better when not overinflated.

I run 60 psi cold on my front towing or not , it's what's on the door pillar on my 2014 3500 SRW. It seems to work for me , tire wear, and handling is okay . I run the Thuren specs the alignment . I rotate every 5K . Running empty on the rear I run 45psi cold . 80 psi. towing the fifth wheel .

 

[Cummins12V98]

I run 60 psi cold on my front towing or not , it's what's on the door pillar on my 2014 3500 SRW. It seems to work for me , tire wear, and handling is okay . I run the Thuren specs the alignment . I rotate every 5K . Running empty on the rear I run 45psi cold . 80 psi. towing the fifth wheel .

I am with you on your front axle inflation but 80 rear seems excessive? How does the tires capacity @ 80psi X2 compare to your rear axle fully loaded?

 

[johnmyster]

I am with you on your front axle inflation but 80 rear seems excessive? How does the tires capacity @ 80psi X2 compare to your rear axle fully loaded?

3500 SRW RAWR is 7,000 pounds. A pair of 275/70r18 is 7,280 at 80 psi, which is what the door jamb sticker lists. I think the 20" fitment is very similar.

Even if not at 7k loaded, some folks prefer/advocate extra rear pressure when towing heavy for lateral stability on SRW trucks.

 

[Cummins12V98]

3500 SRW RAWR is 7,000 pounds. A pair of 275/70r18 is 7,280 at 80 psi, which is what the door jamb sticker lists. I think the 20" fitment is very similar.

Even if not at 7k loaded, some folks prefer/advocate extra rear pressure when towing heavy for lateral stability on SRW trucks.

I completely disagree with airing tires to MAX just because. Tires that are overinflated con't last as long, don't stop as well and sure don't ride as well.

There is a reason tires have weight/inflation charts. Tires say MAX PSI, NOT air to MAX.

 

[johnmyster]

I completely disagree with airing tires to MAX just because. Tires that are overinflated con't last as long, don't stop as well and sure don't ride as well.

There is a reason tires have weight/inflation charts. Tires say MAX PSI, NOT air to MAX.

I don't disagree. I don't inflate to sidewall max cold on any tire that I own including truck and rv. (Our 80 psi camper tires scale at 55% of their sidewall rated capacity.) OTOH, we also don't want excess sidewall deflection and heat causing tires to come apart.

Yet, load inflation tables reflect minimums. We don't know the load in question but it isn't as if 40 psi is appropriate and the user is inflating to 80. For a big fifth wheel on a SRW, 80 may not be far from the minimum given by the tables. After all, for a 3500 SRW the door sticker says 80 psi rear axle. If 10 or 15 psi over what is given by the tables is used to improve handling characteristics, that's well within an acceptable margin that may already be there for cold days, slow leakers, seasonal changes, uncertainty/imbalance of loading, etc.

 

[Turbo Terry]

Yes at the price of these tires I want to get a long life etc . I have been using the tire air weight chart which is very handy. With a tongue weight of about 900 lbs I should be able to get by with something like 65 front and 50 rear until I put my 600 lbs Honda foreman in the back of the truck and maybe bump the rear up to 55 lbs. Tires should last a bit longer at this rate not hauling a 3000 lbs truck camper. That’s pretty hard on tires. Well I think I have a pretty good baseline for when I pick up the new travel trailer in April .. Thanks for the help

 

[Cummins2014]

I am with you on your front axle inflation but 80 rear seems excessive? How does the tires capacity @ 80psi X2 compare to your rear axle fully loaded?

Ron , I am so close to the 7K on my rear axle with the fifth wheel , I am not really worried about being 80 psi , over say 70-75 psi . My towing miles are pretty limited these days . We spend a lot of time in the fifth wheel ,but not a lot of miles getting to ,and from . I weighed a few years ago , but as said I was pretty darn close to max on my 3500 . I don't remember weights , it's been awhile , but felt comfortable with 80 psi . If anything I am probably a little lighter now , eliminating a bunch of stuff that I felt unnecessary . Granted I probably should weigh again ,but as said I'm comfortable with what I am doing . Now the fifth wheel is another matter ,I am running G rated Saliuns , they are rated at 4400 lbs @ 110 psi . Don't need that much , especially with Sailuns. According to my weights ,and the inflation chart if I remember I only needed around 85 psi. I run them at 95 psi , that seems to be a good compromise , fifth wheel rides well . I would think 110 would be a little rough on my fifth wheel ,and unnecessary.

 

[Cummins2014]

I don't disagree. I don't inflate to sidewall max cold on any tire that I own including truck and rv. (Our 80 psi camper tires scale at 55% of their sidewall rated capacity.) OTOH, we also don't want excess sidewall deflection and heat causing tires to come apart.

Yet, load inflation tables reflect minimums. We don't know the load in question but it isn't as if 40 psi is appropriate and the user is inflating to 80. For a big fifth wheel on a SRW, 80 may not be far from the minimum given by the tables. After all, for a 3500 SRW the door sticker says 80 psi rear axle. If 10 or 15 psi over what is given by the tables is used to improve handling characteristics, that's well within an acceptable margin that may already be there for cold days, slow leakers, seasonal changes, uncertainty/imbalance of loading, etc.

I have always felt the same with 80 psi on my rears with my fifth wheel ,as said above in my previous post I am close enough , and see no reason not to run 80 psi towing . Soon as I get to where I am going , I usually air down to 45 psi . Unless just for a day or two, a week or longer , I air down ,don't can't care much for getting beat up in that 1 ton .