8 replies to this topic

[LosAngeles]

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 4x4 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!

 

[Wango]

I have a truck similar to yours, i air down frequently. Though, my tires/wheels are not stock. And i do drive on sand and snow etc.

For trails i go down to about 40-45 psi

for soft sand/snow i go down to 20-22 psi

Have been in the teens once or twice as well.

i carry and arb twin portable air compressor.

Your tires/wheels should be fine with your intended usage i believe.

[rubberlegs]

Have you weighed your front and rear axles?

[LosAngeles]

Have you weighed your front and rear axles?

Yup but I can't find the piece of paper from the scale. Oops. :-/

[smlobx]

Have you weighed your front and rear axles?

 

This is your first step as you probably know. If you can get individual tire weights that would be even better as your left rear tire is probably the heaviest.

 

Then you should look up to find the manufacturer’s inflation tables. Here is the one for Toyo’s  that I run to give you an idea of what it looks like. Goodyear’s data may be similar.

 

https://www.toyotire...es_20170203.pdf

 

Then you should decide what you’re comfortable with. In my case I don’t run my tires below 30 psi with the camper on but that’s just me and my weights. Most of the time I’m at 40-45 off-road.

 

Hope this helps.

Edited by smlobx, 13 January 2021 - 04:44 PM.

[PJorgen]

Inflation tables for sure, and the one that smlobx linked to is a good one!

 

I took a 4x4 driving course from Bob Wohlers and he recommended starting at 50% of the on road pressures based on the inflation tables. At those pressures you do not exceed 30 mph. If needed you can go a bit lower, but then your max speed is even lower. 
 

A bit of trial and error is involved. With my 8700lb GMC 2500 + FWC, I’ve gone as low as 18psi front and 22psi rear, but drive really slowly at those pressures, like no more than 10 mph. 

[rubberlegs]

That makes sense. Driving fast at low pressures can overheat tires.

[DoGMAtix]

I'm no expert, but (don't you hate it when people start their replies to your post that way?)...

We have a slightly lighter setup with our Dodge Ram 2500 and a Hallmark 8' camper, and BF Goodrich T/A KO2's. We routinely drive long distances on rocky 4WD roads in Colorado and Utah, and air down to 35PSI front, 40PSI rear without problem. I agree with others that going lower would be fine (and probably necessary in a pinch) in soft sand, but I hesitate to expose more vulnerable sidewall to sharp rocks by going any lower than the above settings on rocky terrain.

 

Also potentially annoyingly, I am going to offer some unsolicited advice (again, from a non-expert, but...):

Make sure you don't skimp on quality/rating of compressor, we had one give out on us mid-trip once and had to drive slowly back to the nearest gas station to air back up, which was NOT near. Also have had to stand by for far too long while waiting to air up in cold/windy/dusty conditions and that was enough to make me very happy to make the investment. And getting a set of 4 Staun deflators was another great investment. You can put all 4 on to air down simultaneously and jump back in the truck if weather's inclement. You just have to take some time before setting off on your trip to dial them in for the pressures you want to achieve.

[wicked1]

I've got the valve stem removal deflator tool.  It's just one tire at a time, but it's about a minute per tire.