Tire Deflators

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
9,472
Escondido California
I deflate to usually 15 psi, might try lower next time, and inflate to 28 psi, on a 35x12.5x15.
28 psi is more appropriate for a 33" tire, 24-26 is about right for a 35x12.50 when supporting a Wrangler. 24 psi when the TJ is only lightly loaded, 26 when it is fully loaded.

And when offroad, 15 psi isn't airing down all that much where a 35" tire is concerned. The bigger the tire, the lower the pressure that should be run. Before I got my beadlocks, I was regularly airing my 35" tires down to 8-10 psi on standard wheels which is what they're commonly run at offroad. The reason to air down is to increase the tire's footprint size and to allow it to flex and conform more easily to uneven terrain. All in the interest of better traction so the drivetrain doesn't have to work as hard to get the Jeep through difficult terrain. :)


Tire footprint (2).jpg
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
9,472
Escondido California
@Jerry..."a PITA that for some reason that still doesn't make sense never got the tires evenly deflated either."

Your rig is a intresting idea but as you stated it is a PITA. The pressure will never reach equilibrium. It will get close over time but never the same (its a law). As designed there are a a couple of obstacles namely the valve stems but also the T connectors.

These all work to reduce flow which is exactly what you want...a lot of it and fast. Also to work optimally the hose lenghts from each tire to the relief valve should be the same. From a design standpoint you can calculate the flow through each orifice (fluid dynamics) and adjust the componants to optimize the design BUT you will be left with the valve stems which ultimately kill the idea from a time perspective.
Understood (I also studied college-level physics lol) but what always puzzled me was with how it was constructed, and all tires being connected to a common shared manifold, and despite the different hose lengths, all the tire pressures should have equalized closer than they did by the time I needed to disconnect it and move on.
 

Jeepaholic

TJ Enthusiast
28 psi is more appropriate for a 33" tire, 24-26 is about right for a 35x12.50 when supporting a Wrangler. 24 psi when the TJ is only lightly loaded, 26 when it is fully loaded.

And when offroad, 15 psi isn't airing down all that much where a 35" tire is concerned. The bigger the tire, the lower the pressure that should be run. Before I got my beadlocks, I was regularly airing my 35" tires down to 8-10 psi on standard wheels which is what they're commonly run at offroad. The reason to air down is to increase the tire's footprint size and to allow it to flex and conform more easily to uneven terrain. All in the interest of better traction so the drivetrain doesn't have to work as hard to get the Jeep through difficult terrain. :)

Wow. I didn't know you could go that low with no worries of losing a bead. I will try 10 next time, and also try 25 psi on the street to see if it gets smoother. The ride now is actually pretty nice with m/c 3.5 springs and ome nitro sport shocks. Thanks for the tip!
 
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Chinodiver

Member
Supporting Member
I built a co2 tank. 10 lbs, inflates a 35" tire 16 plus times. It is amazing! This is my full deflate/inflate set up. About $250 for all of it. Works very well, and one less thing to worry about needing electrical power hook up.View attachment 16052
I was about to do the same thing, I like the PowerTank concept but their pricing is a huge deterrent. I then came across Instant Air Supply. My understanding is that someone on another forum did an excellent write up on how to build your own including where to source parts at and some enterprising individual saw an unfilled need and IAS was born. I don't know if the guy who did the write up is the same one that started the company but I digress. Mine will be here tomorrow. Added bonus you can get the tank powder coated any color you want but make sure your local shop doesn't have an issue filling a powder coated tank first, seems that some of them do.
Here is a link if anyone is interested...http://www.instantairsupply.com/5-complete-systems?orderby=price&orderway=desc&id_category=5&n=8
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
9,472
Escondido California
I didn't even know there was such a thing as a tire deflator. But can certainly see it making the task easier.
I saw the few name brand models, but I'm too cheap for that. Anyone used this one from eBay?

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/183651955111
That's a knockoff/rip-ff of ARB's and Currie's same-design deflators. What it has that won't work as well is its higher 70 psi range scale that compresses the lower PSI indications so they're not as spread out at lower air pressures making accurate settings more difficult For $20 more I'd rather have the non-knockoff original Currie or ARB deflator with the slightly lower top psi, 60 vs. 70 psi which spreads the usable psi's out more.

That 10 psi top scale difference may not seem like much but I've bitched to John Currie several times over the past 15 years to try to get them to come out with a 30 or 40 psi max scale deflator so lower pressures like 5-10 psi are more spread out.

https://www.amazon.com/dp/B00PADT5PS/?tag=wranglerorg-20
 

chad

New Member
Supporting Member
I just bought the 400P. It's overkill, but usable for a future motor home. And it has a really nice carrying bag. - Just arrived today. Going to play with it this weekend.

VIAIR 400P-Automatic Function Portable Compressor https://www.amazon.com/dp/B000X9B32M/?tag=wranglerorg-20

Also, I want to see if I can couple it with my Noco battery to make it truly portable and not use my Jeep battery.

NOCO Genius Boost Plus GB40 1000 Amp 12V UltraSafe Lithium Jump Starter https://www.amazon.com/dp/B015TKUPIC/?tag=wranglerorg-20

Lee - 2005 TJ 4.0 Auto - Las Vegas
That’s a really good idea with the jump start battery. I don’t why I haven’t thought of that.
 

M35A2

Member
Feb 6, 2019
96
Chandler, TX
That 10 psi top scale difference may not seem like much but I've bitched to John Currie several times over the past 15 years to try to get them to come out with a 30 or 40 psi max scale deflator so lower pressures like 5-10 psi are more spread out.
Is the gauge removable? Might be worthwhile to replace it yourself, if it is. (y)
 

jjvw

0-60 in 18 seconds
Supporting Member
Feb 17, 2018
4,792
Colorado, USA
Is the gauge removable? Might be worthwhile to replace it yourself, if it is. (y)
It is. Recently I made my own Frankenstein single tool inflater/deflater. I couldn't find a 40 or 50psi max gauge, so I kept the Currie 60psi.
78574

78573
 
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