Air Down Tires for Trails

These are hands down the best deflators around. Set it and forget it!

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http://www.toyota-4runner.org/group-buys/219706-jt-brooks-tire-deflators-group-buy-made-usa.html

+1...these are awesome! Thanks again Chas!
 
Thanks, that's about what I figured.

Airing up is the main reason I try to avoid airing down. The pump that plugs into the cig lighter is better than nothing, but still takes a LONG time to get each tire back up to pressure.

Most used and "Best Buy" of trail gear I have (along with the JT brooks Deflators mentioned above).

https://m.pepboys.com/product/details/9357343/01635

I got it for $50 because pep boys always has coupons. It's no arb onboard air compressor, but it gets the job done. I can usually air up from 20psi to stock tire 34 psi in about 2 mins a tire.

It is the same compressor as the MV50 and is Sold at Walmart as well.
Masterflow 12v High Volume Air Compressor / Inflator - Walmart.com
 
I finally mounted a VIAIR 200C under the hood. Definitely some cost there, but it will air up my 33/10.50/15's from 20 to 35 psi in a little over one minute/tire.
 
At 20psi, what is too fast?

I'm still running the original tires and I drive pretty fast on some dirt/gravel roads. I've driven some deep sand with tires at 32psi.
 
Depends on how long you run. Heat build-up is the concern because of sidewall flex. Also depends somewhat on your tire size - larger/wider tires need less pressure to make them stand up straight.

On stock sized tires 30mph should be OK for a number of minutes, and short bursts to 45 should be fine. I wouldn't try to hit 60.

If you're worried, just stop after a short time at speed and feel the sidewalls. If they're still cool you're fine.
 
Here's a couple of pictures of my '94 with 33" BFG's aired down to 20 psi. As you can see, they're far from looking "flat". We ran 30 miles on "good" gravel out to Hite from the Maze in Canyonlands before we aired up again, probably averaging 30-40mph. No problems at all. (BTW, that running board damage was done 5 years ago, not on this trip. Miscommunication between me and the spotter.)

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I usually air down to 20psi on my 33''s and have never had the tire slip on the rim. Now that I am on 37's with headlocks I will be down to under 10psi. Probably 6-8.

The ride comfort on any sort of trail, even it being a dirt road with imperfections is well worth the few minutes of airing down. Anything above 20psi is still safe in my eyes to drive some milage to air back up.

Honest, I drove from Colorado back to Texas once with mine at 20psi because I had totally just spaced it after leaving the mountains. I got shitty MPG, but damn it was a smooth ride. hahah

I am a big fan of the curry tool. You can snag them on amazon for like $30
 
Back in the days before high fuel prices and government CAFE standards, I remember the recommended highway tire pressure for my dad's Oldsmobile was 24 psi front and rear. Rode like a feather bed at 80 mph.

So yeah, tires will run a long way at 20psi or so.
 
Don't you lose ground clearance when airing down?

Why are the sidewalls less likely to get damaged at lower pressure?

I just drove a trail that had lots of loose rocks (up to and beyond football sized). There were scuff marks on the sides of the tires past the lettering to within a couple/3 inches of the rim. I was still running the stock tires at 32psi.

Maybe I should try the same section of trail at 20psi.
 
Don't you lose ground clearance when airing down?

So, I can't resist a math/geometry problem. Assuming a 32 inch tire 7 inches wide, and a 4400 lb vehicle, the axle height difference going from 35 psi to 20 psi should be about 3/8 inch.
 
So, I can't resist a math/geometry problem. Assuming a 32 inch tire 7 inches wide, and a 4400 lb vehicle, the axle height difference going from 35 psi to 20 psi should be about 3/8 inch.

I checked using different assumptions and got small numbers like that. I have to try lower pressure when I can.
 
I went up yesterday without airing down, I am assuming its a must? What terrain is it best to air down on? Should I air down on loose rocks?
 
It's not a "must". Just makes it more comfortable on rough roads and gives you a bit of an edge on difficult or soft terrain. Most casual offroaders probably never air down - I didn't for many years. Unless you have a decent onboard air system it's not really practical.
 
I went up yesterday without airing down, I am assuming its a must? What terrain is it best to air down on? Should I air down on loose rocks?

if im going to be more than a few minutes I air down as soon as I leave pavement.
even if im just driving on gravel forest service roads.
 
I found that airing down the stock Nitto Terra Grapplers to 25 psi on the TRDP worked very well for mixed rock, sand, water crossings and 35-40 mph washboards.

As for BFG AT and MT tires, I've actually removed the valve stems and run 0 psi for "emergency" sand and snow vehicle extrication. Of course, airing up after getting unstuck; but it's a huge advantage of the strong side walls.

-H-
 
But remember:
Airing down also allows the tire to spin on the wheel, particularly in high torque/high traction situations experienced off road (low range on rock)

Unless you have beadlocks, watch that you are not moving your tires on the wheel which will not only knock the tires out of balance, the out of balance condition will be far worse than having no balancing weights at all.

Choices:

1.) don't air down.

2.) air down but chalk the tire and wheel at the valve stem to indicate any movement at the end of the run when you air up. This will tell you if you need to head to your nearest tire shop.

3.) run continuous balancing media in the tires themselves with filters in the valve stems to keep the media from entering the stem at air down.

4.) get beadlocks and run whatever pressure you want

I have a 4Runner with double bead locks and CTIS and I have a new TRD Pro that I wheel often without airing down at all.

It is a different experience with different challenges but both are lots of fun.

How do you have CTIS? What system is it?
 
Any advice/feedback on other 12 Volt Portable Hi Volume Air Compressor's?
I've been looking on Amazon and found the Viair 00088 88P Portable Air Compressor.

As for Tire Deflator's, any additional suggestions? Mentioned so far - ARB and JT Brooks
 

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