Inflating Dually Tires

[BradKW]

Before I drove to Miami, I did check the tire pressure...all read about 40 psi so that was good. However, I failed to actually check the recommended PSI...40 fit with my experience and I didn't question it. 

Turns out recommended pressure for front is 65psi and 80psi rear. On the bright side, there were no problems on the drive and I might hope to get better milage now.

I bought a inflator for dual tires, like this one but longer:  

It works fine, all except one inside rear tire. I can see the valve, I can put inflator on the valve somewhat, but the angle is bad...rim hole on outside tire is forcing and angle that the valve doesn't bend enough to, so it doesn't seat on. Is there any tricks or alternative approaches?

Also, if I need to get air while traveling, what sort of adapter do I need to carry so I can use the inflator with standard ones you find at gas stations?  tia...

 

[Gunny]

Brad, you probably know but they make dually equalizers for airpressure. One nozzle and the air pressure will equalize.

 

[SternWake]

I'd recommend carrying your own compressor rather than relying on gas station compressors, many of which cannot do more than 50PSI and cost a Quarter for the privilege of deflating your tire lower than when you came in.

I modified a MV-50 with standard air fittings. and some other improvements
https://www.amazon.com/Industries-MV50-SuperFlow-12-Volt-Compressor/dp/B000BM8RT8

These and similar compressors can be had for as little as 50$ elsewhere or under a different name.

They need a little spit and polish to work as well as the design could. The QC of the wiring is not impressive. There is a relay inside, and under sized wiring and little to no stress relief on that wiring. Also the head bolts are finger tight. They are extremely simple in design.

Any 12v compressor you decide upon should have alligator clamps to hook to battery terminals directly. Those with Ciggy plugs are significantly slower and more apt to failure. Since you likely already have a 120V compressor, perhaps you might want to carry that and run it from inverter.
There are some considerations when modifying the MV-50 with better air fittings. If the tire chuck is not passive when motor is running, it can build up 150+ PSI in seconds and something will blow.

I can elaborate on the MV-50 modifications I did if there is interest. It is now an impressive and reliable 12v compressor, even with 14awg leads. It pulls 16 to 20 amps depending on load and voltage it is allowed. I bought it 10 years ago in Pep boys for about 60$. Modifications came later after i became disgusted with screw on original tire chuck.

I've not researched more recent 12v compressor offerings. Viair used to be the Bees Knees, but then they had to move production to China too, so their good name is established, and recent quality downfalls have not yet caught up with that good name.
Standard business practice it seems. Spend less on production, more on marketing, to hell with quality, time to cash out.
I also use my compressor to prime my water pump and adjust my leaf spring helper Airbags, as well as others bicycle tires or pool toys. While I have a 3.5 gallon porter cable pancake compressor(POS), I can usually accomplish the vehicular related inflation task faster and easier using my MV-50.

Regarding the dually inner tire stem, I've no solution to offer. Bad angles need to be changed somehow to be less bad.

 

[highdesertranger]

I am not a big fan of the equalizers, they make it like one tire so if you have a flat on one they both go flat, which cancels a big plus of duallies. they also make extenders that screw on to the valve stem to bring the inner tire fill to the outside, but most have a bad rap for leaking. you can also get a different shaped inner stem that makes filling easy. go to a commercial tire place and tell them what you need they will fix you up. highdesertranger

 

[rvpopeye]

X2 ^^^HDR get new solid bent to fit stems.

I hope you lucked out, running tires at more than 10% below recc. pressure can do damage to sidewalls.

 

[SternWake]

Seems that simply adding the equalizers or the leaky extenders would also throw off tire/wheel balance.

Not sure how much an issue that would be for a dually box truck. But it would have to contribute somewhat, to axle's outer bearing wear.

I have seen premature sidewall cracking by running underinflated for too many miles as well.
perhaps 80PSI tires would not show the damage as easily as 32 to 50 PSI passenger car/light truck tires.

Lots of used car dealers underinflate tires to make vehicle ride smoother for the test drive. I left Discount tire with New Kumho LT AT tires inflated to only 32 PSI front and rear, when 45PSi was more appropriate for the tire and the load, but 32PSi is on the door sticker. I thought 'Man these tires are smooth and buttery', until I checked PSI and then inflated them to 42 to 44 or so.

 

[highdesertranger]

I am old enough to remember the old wheel balancers that balanced the tire on the vehicle this actually balanced the whole rotating mass, tire, rim, and brake drum/rotor. a far superior balance. imo. and yes anything added to the rotating mass will throw the balance off. highdesertranger