Deflating tires. On the dirt.

[afk314]

Disclaimer: I've been around here long enough to know that tire pressure threads get religious. And I've also learned that hard and fast rules generally don't exist in the real world and even if they did they would require knowledge of variables that most of us couldn't measure. So, I understand whatever winds up in this thread (if anyone even attempts to take it on) will be opinion and subject to debate. That said:

My AS has been on many rough roads. It has a custom 4" lift and just about everything that you'd expect to happen on a modern trailer that sees a lot of dirt has happened to mine (maybe outside of the microwave hitting the floor but pretty much everything else). However, as I get older and wiser I'm now willing to plan things out a little better.

I have an upcoming trip which will take me over 20+ miles of dirt roads with mild-to-medium washboards. Of course, it'll be slow going and precautions will be taken sufficient to the case. However, I'm thinking about deflating a bit on this one. My 15" GY Endurances look like they can handle ~40PSI based on my measurements of my trailer weight and the inflation table found online. (Total trailer weight of 7300 distributed over 4 tires). However, this is for "normal highway speeds" - which I won't even be close to reaching. Instead, I'd say my max speed will be closer to 10-15 mph. Granted, I'll be contending with rocks and everything else.

My question is - do you ever deflate on longer dirt roads? If so, what have you learned and how low will you go for your rig? Is deflating the tires on the truck a good idea, too?

Thanks for reading!
Adam

[ROBERT CROSS]

Sand...yes.
Hard packed dirt...not so much.
Speed effects shock more than TP.

Bob
🇺🇸

[GetawA-S]

I always thought the purpose of deflating was to improve the grip of the driven wheels, which implies increased friction/drag. Wouldn’t deflating the trailer tires amount to throwing out a small anchor? It doesn’t seem prudent wherever “digging in” is a possibility.
Someone once quoted Wally Byam’s solution to traveling over rough roads, “Slow Down!”
Happy travels!

[mojo]

Deflating on sand to keep from getting stuck or unstuck is usually a soft environment. Off-roading with deflated tires on hard, rocky ground can cause a tire to pop the bead and deflate depending on the firmness of the sidewalls. Go slow...

[JonDNC]

So I’m going to take a slightly different approach which is take 10lbs off normal. So in my case normal is 65 so if I was doing a long drive on rough road I’d deflate to 55 or so. Same on the truck.

Then as soon as I hit pavement take things up 10 so back to normal.

Obviously need to have a pump that can move the necessary amount of air/pressure.

[Action]

Dirt road in general no.
Dusty road no
Sand over dirt road no
Loose dirt on road in general no

Deeper sand or loose snow, that has some merit on a longer traveled road.

Deflating tires is to spread the load over a greater surface. Think of an over inflated tire as having a bulge in the center tread. The weight of the load is concentrated in the center of the tread.

Letting air out spreads the load over greater surface area of the tire. It also greatly reduces the load capacity and the speed that should be driven. And know that road tires are not well suited or designed for travel in deeper sand. I would suggest that if you find yourself in a situation that the normal road tires on a travel trailer are digging in deeper to the loose surface, a lot of thought may be required as to continuing down that path.

Action

[Goin camping]

Desert boondocks here.

You can let some air out to soften the ride. May or may not work as smoothing wash board roads is a balance of speed, tire pressure, length of vehicle(s) and height and width of the washboards.

I encounter wash board roads every time I am out in the desert. Without a trailer I add speed and glide along top of the washboards. With a trailer. I slow the down to turtle speed. Easiest way to cope with it.

Best to you.

[B. Cole]

This is low speed/ very short distance/no traffic work.Its not like you're crossing the continent like our covered wagon kin did.With 4 wooden wheels
Lowering air pressure like noted above will provide more " shocking action".
As most noted above, slow it way down, will be fine.

[LNBright]

Originally Posted by mojo

Deflating on sand to keep from getting stuck or unstuck is usually a soft environment. Off-roading with deflated tires on hard, rocky ground can cause a tire to pop the bead and deflate depending on the firmness of the sidewalls. Go slow...

I've been in some 'rock gardens' where you had to deflate in order to have enough grip on the rock....

[LNBright]

Originally Posted by afk314

I have an upcoming trip which will take me over 20+ miles of dirt roads with mild-to-medium washboards. Of course, it'll be slow going and precautions will be taken sufficient to the case. However, I'm thinking about deflating a bit on this one. My 15" GY Endurances look like they can handle ~40PSI based on my measurements of my trailer weight and the inflation table found online. (Total trailer weight of 7300 distributed over 4 tires). However, this is for "normal highway speeds" - which I won't even be close to reaching. Instead, I'd say my max speed will be closer to 10-15 mph. Granted, I'll be contending with rocks and everything else.

My question is - do you ever deflate on longer dirt roads? If so, what have you learned and how low will you go for your rig? Is deflating the tires on the truck a good idea, too?

Old off-roader perspective: For dirt roads, be they good or bad, I usually don't touch the tires of my vehicle. If I'm at a 4x4 'park', something like Uwharrie or what-not, I'd air my vehicle down for that if I'm hitting the rock gardens, but, if I'm just rolling the trails and not tackling the rocks, I'd not. If I head for the Outer Banks and am going to drive on the beach, I air down my tires.

But for all those: it's for the vehicle: the steering tires or the drive tires.

For a camper that's behind being towed, when you're running down the highway, you need to ensure you have enough air pressure in the trailer tires to support the weight: as you're running Endurance tires, and have four of them, I'd not 'worry' about them: just ensure they have adequate pressure for the weight for the road.

Once you cut your speed to half, the trailer won't care: it'll be able to handle nice and slow: you still have to maintain enough air pressure to support the weight, but the trailer's tires aren't steering, they aren't driven, they're just rolling along for the ride. As long as they're not 'over-inflated' to where you'd be popping rivets, then I'd not adjust the trailer tires.

[Peter417]

I love this topic.

Pay close attention to point 2 and 3 and think about how that might apply to your rivets. Ride quality goes way up with lower pressures.

https://www.youtube.com/watch?v=KXAKVyKYJBw

[pteck]

Originally Posted by afk314

Disclaimer: I've been around here long enough to know that tire pressure threads get religious. And I've also learned that hard and fast rules generally don't exist in the real world and even if they did they would require knowledge of variables that most of us couldn't measure. So, I understand whatever winds up in this thread (if anyone even attempts to take it on) will be opinion and subject to debate. That said:

My AS has been on many rough roads. It has a custom 4" lift and just about everything that you'd expect to happen on a modern trailer that sees a lot of dirt has happened to mine (maybe outside of the microwave hitting the floor but pretty much everything else). However, as I get older and wiser I'm now willing to plan things out a little better.

I have an upcoming trip which will take me over 20+ miles of dirt roads with mild-to-medium washboards. Of course, it'll be slow going and precautions will be taken sufficient to the case. However, I'm thinking about deflating a bit on this one. My 15" GY Endurances look like they can handle ~40PSI based on my measurements of my trailer weight and the inflation table found online. (Total trailer weight of 7300 distributed over 4 tires). However, this is for "normal highway speeds" - which I won't even be close to reaching. Instead, I'd say my max speed will be closer to 10-15 mph. Granted, I'll be contending with rocks and everything else.

My question is - do you ever deflate on longer dirt roads? If so, what have you learned and how low will you go for your rig? Is deflating the tires on the truck a good idea, too?

Thanks for reading!
Adam

Off-road bumps and corrugations can really beat the snot out of trailer and cars. Airing down is not just for traction, nor floatation... it's also important to improving the ride and control, and making the tire act as an integral part of the suspension.

Your intuition is spot on. I would highly encourage you to air down and for a longer stretch like that would be well worth the inconvenience. So long as you also have the ability to air up which can take a pretty good size pump for 8 combined tires.

Yes, load ratings established for tires are for rated load, up to the max speed of the tire, on the hottest of days. Off-road, where speeds are significantly lower, there is ample margin to air down. It can also protect the tire from punctures as it helps the tread contour against sharp objects. Just watch the sidewall depending on the types of surface you're on. I would aim for the rocks to have meatiest part of the tread face them rather than potentially skirting them and risk the sidewall catching.

That said, airing down 10-15 PSI for highway tires is not out of the question depending on the weight of your trailer. No worries with practically zero chance to losing a bead at those pressures on the trailer. You'll have to test as Goin camping is right as it's often a combination of variables. It's also a bit tougher to get direct feedback as to how the trailer is doing. My tow vehicle aired down from 44 PSI to 15PSI (albeit with AT tires and without trailer in tow), will glide at freeway speeds over the roughest of corrugations. It's a huge difference from 44, to 30, to 20, with every drop in pressure hugely contributing to ride quality.

[ITSNO60]

I used to air down my truck from 60 to 25 lbs and boat trailer from 60 to 25 and it helped immensely on the wash board roads, but when I asked in numerous places, including Roger Marble, I could not get a definitive answer if this will cause permanent damage to the tires. Tire experts maintain that running low will cause sidewall damage that may not show up till much later. I decided to only drop the tires to 40 and it still helped a lot but I feel better not letting the sidewalls flex as much, and the speed is kept very low in all cases.

I think if you stay within the tire manufacturer's recommended load and inflation tables you won't be airing down a lot but I think it would be safer. It's surprising how much just a little bit make a difference especially with a light load.

[Peter417]

How many of you are running an on board air system? I have a Viair 450H setting in the garage waiting for me to stop working on the AS and get it put in. I plan to put in a couple of quick releases on the truck and then carry a couple of lengths of light weight air hose. One just long enough the get to the trailer and the other enough to get to the all the tires on the truck. I am still thinking it all through.

[pteck]

@ITSNO60, it can help to have a non-contact thermometer to know the limits of airing down. Anywhere under 180*F would be safe, as thermal limits for most rubber tires are in the vicinity of ~220*F. Another way to know is if you're airing down, and checking the pressures later are significantly higher again, probably airing down too far and the tires are heating up too much. Though I would say for a highway type tire, you'll not want to go anywhere near the thermal limits as the risk to sidewall punctures is probably greater with too little air.

@Peter417 Yes to On-Board Air (OBA). Without a good method to air up, it's going to be hard to be convinced to air down. Which is unfortunate because airing down is literally the single best tool for off-road travel.

Dual Viair 444C to fill up my larger 35" tires on my TV. Otherwise it can take an hour plus to fill that many tires to highway towing pressures. I also made a dual purpose extension hose that can help me reach the trailer tires from a tailgate mounted quick release compressor port. It doubles as a splitter that I can use to fill 2 tires at once, to balance pressure on an axle.

[ITSNO60]

Originally Posted by Peter417

How many of you are running an on board air system? I have a Viair 450H setting in the garage waiting for me to stop working on the AS and get it put in. I plan to put in a couple of quick releases on the truck and then carry a couple of lengths of light weight air hose. One just long enough the get to the trailer and the other enough to get to the all the tires on the truck. I am still thinking it all through.

Here's mine, Viair 450 with a 2 gallon tank both mounted under truck, air chuck at running board and air intake behind back seat to keep air clean & dry. This is on my F-350, unfortunately I can't afford the space or weight on my Sprinter motorhome so will be carrying a small portable. Don't plan on taking the MH off road anyway but the F-350 is the dedicated Mexico offroad vehicle

[ITSNO60]

pteck that is a good idea, I'll throw the temp gun in the truck before we leave for MX Thursday. How lucky you are to have room under the hood for 2 compressors, I'm full up under the hood

[pteck]

Nice ITSNO60. I see a second battery peeking there.

The space I used for mine would be where the second battery would be on some variants. Moved a couple things around and fortunately had just enough space. I had a single pump which was taking me 30+ minutes to fill 4 tires, so more pump was really needed to enable airing down lower with less time consequence. Wife and kids aren't so patient when they're hangry. Nor as happy to go off-road if it's too bumpy.

[Ken G]

Airing down not only improves traction but adds compliance to your tires that compliments the travel of your suspension. Try it in small increments say 10# at a time and you can do TV tires too to lessen shocks thru the ball. Drive slowly, carry an inflator and monitor closely.

[drbrick]

Our F-150 is equipped with the Off-Road Package. We upgraded this with BFGoodrich all-terrain TA KO2 lt275/65r20/e 126s 3750/3415 – the weakest link is always the tires. So we looked at load ratings and decided to go bullet proof with E Rated tires primarily because 90% of our camping is Boondocking (gravel/forestry roads). We did the same with our AS with GYE. We also carry our ViAir compressor which allows us to air down and air up as needed if the off road travel is rough washboard or very soft. We also will lessen the tension of our weight distribution system (we installed SumoSprings to assist in sagging support of the rear of the truck in order to maintain steering when we lessen the tension of the weight distribution for these situations). It is surprising the difference it makes to the ride by reducing 10lb - we no longer have cabinets coming loose and screws on the floor. By the way we DO reduce our speed - Last summer it took us over an hour to travel 5 km to one of our favourite campsite where we stay usually 14 days so it was will worth the slow go!