Home Forums Truck Camper Adventure Forum F350 tire airing down ranges w/ truck camper

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    • #48004
      john.
      Participant

      F350 tire airing down ranges w/ truck camper

      Hi all

      I’m doing research and getting opinions and info about airing down pressure ranges (I know it varies a lot depending on tire, load, rig, conditions, etc)

      We have a 4×4 F350 (2020) CrewCab with 8’ bed – single rear wheels (SRW) ….. plus a truck camper about 9.5 feet long on the back.

      Tires are the shoes it came with – Load range E – GOODYEAR WRANGLER – “ALL TERRAIN ADVENTURE” LT275/70R18

      (and overall i am very happy with them, for what it is worth. I do NOT want to change tires – they ride great, very quiet on pavement, and decently knobby, etc)

      Total weight (wet, loaded) is 11,300

      Now obviously we won’t be doing any hardcore wheeling…..

      and I won’t seek out soft sand or soft deep snow……

      and maybe I never need to air down, ever….

      but in the future – if we suddenly found ourselves in a position where we wanted / needed to carefully drive off-road, on soft snow, soft sand, and wanted to stack the deck in our favor, I could air down somewhat to make the contact patch bigger.

      I believe with these stock rims and these tires I should not go below 20 psi (does this sound about right for this rig?)

      and I do know i’d need to air back up before highway driving. 🙂
      and yes I’d have a capable air compressor with me….. to air back up….
      and likely air back up for any road driving of more than a 1/2 mile or so…..

      but any suggestions, just for future reference?

      Thanks!

    • #48005
      Joel
      Participant

      I can’t help, but I am watching this thread with interest.

      I would add another question: A tire’s load rating is at maximum pressure, so I guess airing down reduces the load capability of the tire. Would this only apply at highway speed or would it also be a concern at low speed when wheeling?

      I know we have some off road TC guys on this forum. Looking forward to their input.

      Joel

    • #48019
      Mello Mike
      Keymaster

      Great question. We published an article on this very topic.

      Off-Road Tips: How to Air Down Your Tires

      We recommend you check it out. In short, this is what we recommend for 10 ply SRW Load Range E (max. 80 psi) tires:

      Firm dirt surfaces – 50 psi front/55 psi rear
      Rough and rocky surfaces – 35 psi front/40 psi rear
      Sand – 25 psi front/30 psi rear
      Soft deep sand – 20 psi front/25 psi rear

    • #48021
      sourdough
      Participant

      My Tiger/Ram diesel 4×4 was a dually. Terrible traction sand or any soft terrain. I did the SRW conversion and installed HD wheels and tires for the 11,200 lbs it weighs.During my research for suitable wheels and tires, I contacted the manufacture Nitto. Rep. said what tire and load was I asking about. I told him, Ridge Grappler 305x65r 18 “F” rated for 3,900 lbs. and I have a 3,250 lb. load per back tire. He said, “never air down”, it would likely damage the internal plys. I was shocked, I said, I’ve been airing down my 4×4 tires on Jeeps and Toyotas for 40 years. He said the weight on those tires compared to their load capacity was minimal. Being the jackass that I am, I’ll still air down to try and self extract if stuck(hasn’t happened) but I would never run them that way. BTW, My Tiger is not an off road vehicle and I only use 4wd when 2by limited slip traction isn’t getting it. I have a Wrangler Rubicon on 37” M/T tires currently for off roading.I air them down to low teens.
      BTW, the Nittos now have 50,000 plus miles on them and have a strong thread depth still. Probably go another 15,000 before any concern and I like to pull a tire out of service earlier than most.
      Bottom Line, I say talk to the tire manufacture, then do what feels right to you haha

      2012 Tiger CX Ram diesel 4x4

    • #48025
      john.
      Participant

      My Tiger/Ram diesel 4×4 was a dually. Terrible traction sand or any soft terrain. I did the SRW conversion and installed HD wheels and tires for the 11,200 lbs it weighs.During my research for suitable wheels and tires, I contacted the manufacture Nitto. Rep. said what tire and load was I asking about. I told him, Ridge Grappler 305x65r 18 “F” rated for 3,900 lbs. and I have a 3,250 lb. load per back tire. He said, “never air down”, it would likely damage the internal plys. I was shocked, I said, I’ve been airing down my 4×4 tires on Jeeps and Toyotas for 40 years. He said the weight on those tires compared to their load capacity was minimal. Being the jackass that I am, I’ll still air down to try and self extract if stuck(hasn’t happened) but I would never run them that way. BTW, My Tiger is not an off road vehicle and I only use 4wd when 2by limited slip traction isn’t getting it. I have a Wrangler Rubicon on 37” M/T tires currently for off roading.I air them down to low teens.

      BTW, the Nittos now have 50,000 plus miles on them and have a strong thread depth still. Probably go another 15,000 before any concern and I like to pull a tire out of service earlier than most.

      Bottom Line, I say talk to the tire manufacture, then do what feels right to you haha

      Thanks for the info….. yeah i wondered about the internal construction with a big load like ours…..

    • #48067
      Ron
      Participant

      Hi John

      I have a 2011 F350 with a Bigfoot 3000 9’11” camper. My camper dry weight is 3100 lbs, my truck max payload is 4000 lbs, so I am maxed out when loaded. I have 265 70R 17 BF Goodrich AT tires. I always have my fronts at 60 PSI and my rears at 70 PSI given the heavy load. I only air down for beach driving in soft sand. I air down to 30PSI on the rear tires and 25PSI on the fronts. You will be amazed where you can go when air down. I tried for the first time a few years ago and was impressed. Try it out when your with another truck sometime just to get the confidence.

      Ron

    • #48184
      Jefe4x4
      Moderator

      Mike’s tire pressure numbers are a nice average to go by.
      I get even more anal about tire pressure using a long built up experience in sand running. How tall is your sidewall? The taller the better for deflating.
      That’s why i still ran 16 inch wheels on my 2001 Dodge Cummins: lots of sidewall for deflating. It’s all a feel of the surface you are going to negotiate; the weight of your TC; how hot the day is; how good your air-up device is; how wide your rims are. Why it that? There is sand and there is sand. I’ve tried over the years to take a measure of how soft and/or bottomless the sand is.
      Tires now-o-days are very tough compared to tires 30 years ago.It’s very difficult to injure them.
      I’ve driven all day in our old Lance/Dodge setup with 10 inch wide super single steel rims on the rear and 7.5 in. wide stock steels on the front.
      front tire pressure: 28 pounds
      rear tire pressure: 20 pounds
      Why the discrepancy? The wider your rim is the less actual air pressure you can use for the same, “squat” or sidewall bulge. Also, when using very stiff truck tires, sometimes you have to go even lower. You just don’t want to pinch the sidewall on a rock.
      I’m not sure yet how low to go on our new Ford’s stock 18×8 inch wheels. I suspect a good trail running pressure is: 28 front/30 rear. I’ll be able to tell once we start letting air out at the trailhead of El Camino del Diablo.
      You just need to keep your eye (hand) on how hot the tires become. That means driving slower than you think to keep the temp down.
      Hands on experience is better than anything I could contribute.
      jefe

      2020 Ford F-350 XLT FX4 4WD SRW SB SC 7.3L Godzilla Gas TorqShift 10R140 397 amps dual Alt dual batts Frnt Dana 60; Rr Dana M275 E-locker 4.30's 4580/4320/4066# payload 7243# curb wt. 11,300# GVWR 5-er prepped. 2020 Northstar Laredo SC, 12v compressor fridge, cassette, 320w Solar sub zero insulation.

    • #48291
      Anonymous
      Inactive

      If I understand correctly, once aired down the big Do’s and Don’ts are…
      1. Don’t speed up for any distance that would cause the tires to quickly overheat and blow.
      2. Don’t turn the steering wheel quickly or against hard resistance as you can separate the tire bead from the rim.
      3. Don’t push or pinch a sidewall against a rock that could cause the tire bead to separate from the rim.
      4. Do have a shovel and some type of heavy planks for self extracting.
      5. Do have an appropriate tow strap/chain for your rig weight.
      6. Do be prepared to walk out on your own if you are not traveling with a companion. Or maybe worse, be prepared to walk out with a wife who already said she thought this was a bad idea.

      Questions,

      1. Is there anything else that should be added to the list?

      2. I know having the camper limits how much of a side tilt to take and that it varies depending on if you have a hard-side or pop-up. Is there a side tilt angle to worry about that would cause the tire bead to separate?

      3. Also, is there any hard guidance on whether dually tires can touch or not?

      Thanks,

      Stan

    • #48465
      Jefe4x4
      Moderator

      Stan,
      Looking at your AF 1150 and all your extras, I would not stray too far off into the sand. The problem here is weight and dually’s. Heavy dually’s typically don’t do well in deep sand or any sand for that matter. It takes a long time to deflate six tires down to a usable pressure for sand. The pressure for duals is 5 or so pounds higher than for a single rear wheel. If you really want to get well off into the sand, be sure to have a great way to re inflate the tires. dually’s typically are narrow on a narrow rim without much sidewall for deflating. Purchase the best, most expensive 100% duty cycle 12volt high volume portable air compressor made for big rigs. Take 2 or 3 high quality tire pressure gauges (they are notoriously inaccurate) and the final thing is to take a friend with a similar weight TC along with you that has a lot of vehicle recovery experience; and a 20K tow strap (no chain) and D rings to attach to whatever recovery attachment points you have.You really need secure hooks or points for recovery. A lighter weight ‘friend’ will not do.
      I’ve owned 13, 4WD’s over time; half of them with a winch; many with full locking diffs; wide rims for deflating, over sized tires, big clearance and used my winches hundreds of times for extractions. I took that experience and applied it to a TC which weighs twice as much as all my Jeeps, Scouts, and Land Cruisers.
      Some who insist on taking a dually on sand will put a 1/2″ spacer between the rear wheels to allow the duals to run at a lower pressure. It takes a while to heat up duals, even when they are touching.
      Finally, if you insist, go out and make your own mistakes and worry through a way out of them….with that same sized friend’s rig with a winch and sand travel moxey. This was my 1st 4WD campmobile in 1967. 1949 Willys Utility Wagon with a Chevy V-8 and my first springs over axle attempt. The 2nd is my 1982 CJ-8.

      2020 Ford F-350 XLT FX4 4WD SRW SB SC 7.3L Godzilla Gas TorqShift 10R140 397 amps dual Alt dual batts Frnt Dana 60; Rr Dana M275 E-locker 4.30's 4580/4320/4066# payload 7243# curb wt. 11,300# GVWR 5-er prepped. 2020 Northstar Laredo SC, 12v compressor fridge, cassette, 320w Solar sub zero insulation.

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    • #48470
      Anonymous
      Inactive

      Thanks, Jeff! I appreciate the detailed info.

    • #48831
      Squish
      Participant

      We have a 2000 F350 SRW longbox, with a Bigfoot 1500
      We run the stock Ford 16″ Alcoa rims with the Goodyear Wranglers (I forget what size they are)
      We looked into the safest low pressure to run the tires for our weight, and printed a little label for the inside of the drivers door jam for max low and regular pressure and when we air-down I just read the number, I can’t off the top of my head recall that pressure.

      We don’t “wheel” our rig but we do spend some time on forest service roads, mostly in the Western USA, so we air down mostly for comfort or for traction if it’s sandy. It makes it a bit nicer especially on corrugated/washboard roads.

      We don’t go very fast when we are aired down, but then we subscribe to the school of thought of off road driving by going just quick enough to not get stuck.

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