Help Me - frustrated by dualies

[Bentspoon]

Hello All,

I am fairly new at RVing having recently purchased a Class C Coachmen. This is my first encounter with dulies. Now I pride myself on getting the best equipment for the job as far as I can perceive it. I also take safety advice seriously. I am smart enough to know I have lots to learn. Anyway, I have determined what air pressure I need for my type of tires and load - 60 psi in the dualies. I determined early on that I could not fill these with my current compressor so I went out and got one of those RV 12 V compressor with quick disconnect and the gun/meter. It had a special bent chuck that, I assumed, was to help with dualies. But it is bent in the wrong direction. I went to check/fill the tires before a trip and couldn't do it so I was forced to got down to Les Schwab. They had a standard chuck
For my next trip I got a standard chuck and tried it on one of the extenders. The extender got stuck open and took me several seconds to get it unstuck losing massive pressure in my face. tried it again and the same thing happened. Back down to LS. They pulled out the core which had a long shaft because it is an extender. They told me they don't use extenders for this very reason. They did not have a replacement so they put a gator on the stem. Now is buried back in there.
So I went out tonight and I find that the standard chuck will not align with the outer dually stems. They point inward. I had to remove the hub caps and still the angle was not obtainable so that I could not get a seal on the valve stem.
At this point the spirit of Sam Kennison entered me -- AAAAAAHHHHHHH AHHHHHHHHHHH AAAARRRRRRGGHHHHHHH AAAAAHHHHHHHHH

Please help me. I am now paranoid to approach my tires. I think they are laughing at me. What is the answer?
Bentspoon

[Scrapper]

Originally Posted by Bentspoon

Hello All,

I am fairly new at RVing having recently purchased a Class C Coachmen. This is my first encounter with dulies. Now I pride myself on getting the best equipment for the job as far as I can perceive it. I also take safety advice seriously. I am smart enough to know I have lots to learn. Anyway, I have determined what air pressure I need for my type of tires and load - 60 psi in the dualies. I determined early on that I could not fill these with my current compressor so I went out and got one of those RV 12 V compressor with quick disconnect and the gun/meter. It had a special bent chuck that, I assumed, was to help with dualies. But it is bent in the wrong direction. I went to check/fill the tires before a trip and couldn't do it so I was forced to got down to Les Schwab. They had a standard chuck
For my next trip I got a standard chuck and tried it on one of the extenders. The extender got stuck open and took me several seconds to get it unstuck losing massive pressure in my face. tried it again and the same thing happened. Back down to LS. They pulled out the core which had a long shaft because it is an extender. They told me they don't use extenders for this very reason. They did not have a replacement so they put a gator on the stem. Now is buried back in there.
So I went out tonight and I find that the standard chuck will not align with the outer dually stems. They point inward. I had to remove the hub caps and still the angle was not obtainable so that I could not get a seal on the valve stem.
At this point the spirit of Sam Kennison entered me -- AAAAAAHHHHHHH AHHHHHHHHHHH AAAARRRRRRGGHHHHHHH AAAAAHHHHHHHHH

Please help me. I am now paranoid to approach my tires. I think they are laughing at me. What is the answer?
Bentspoon

Duallys need air chucks like the ones below, either should work. And any auto parts dealer should know what you need. If they don't, then they shouldn't be in business.

[A32Deuce]

How did you determine 60lbs? My class c is 75 front and 80 in the dual rear.

[Bentspoon]

The PSI determination comes from Michelin RV tire charts for my size tires.
We have a nearby DOT truck scale that you can just drive up to - read out is in the window. I determined that front axle load (GAW front) = 3860 lbs (max rating is 5000). GAW Rear = 7540 lbs (max rating is 8500). The chart states to use weight supported by one side of the axle and says to use the heaviest as your factor. My load is well balanced so I simply divided in half. There is a separate chart for single and dual. Therefore I have 1930 lbs on front tires and 3770 lbs on rear. The chart yields 50 psi and 55 psi (I rounded to 60 since I have added a bit of weight. My C is 24'.
Maybe I have made a mistake but these tires look good and ride smooth under these pressures. I am just tired of being dependent on Les Schwab although I have to hand it to them. Most courteous. Always free. Blows me away.
Bentspoon

[A32Deuce]

You don't have a tire sticker at the drivers door? I like going with the manufactures recommended pressure and maybe go higher but never lower.

[Delco Bobby]

Originally Posted by A32Deuce

You don't have a tire sticker at the drivers door? I like going with the manufactures recommended pressure and maybe go higher but never lower.

I believe the door sticker is the max pressure for that chassis. Knowing the actual weight allows one to adjust pressure to tire manufacturers specs for that weight.

I normally run about 5 to 7 LBS under the sticker for a better ride at my weight. that is still above what the specs say.

The sun seeker I had I ran at 70 on the rears but the sticker said 80. Some were/are running at 65 after determining their weight.

[Wolverine 1945]

Originally Posted by A32Deuce

How did you determine 60lbs? My class c is 75 front and 80 in the dual rear.

I think Deuce is right on !!!
I have found the only way I have any luck adding or checking air in the inside dully is to to hold flexible extender with a pair of needle nose pliers !!!
It would also be very helpful to have 3 hands !!!

[redleg719]

Most rv stores sell curved extenders or flex lines to attach & clip to outside wheels I have driven a dually for over 35 yrs & used these. Can also get online from EBay & Amazon.

[Jestercyco]

Look on Wheel masters web site for a system to fill both tires at one time. Duel tire inflation systems. I use these on one of the duel tire set up that I use to have. It filled from the front of the tire and equalized pressure for the 2 tires.
Jester

[A32Deuce]

My door sticker is run pressure from Ford not max pressure for tires. That is on the sidewall of the tire. I feel if you don't know what it should be then run max and watch tread wear closely. Let air out a couple pounds and check wear again and repeat. If you know your weights then use a tire chart but we on the side of higher.

[Bentspoon]

I just got back and I am reading replies. I may reiterate what others have said. Apparently there is a misunderstanding. I am using Michelin specs for load. Max load is printed on the door as a guide. I use the proper chart for the load on the type of tire as recommended by the manufacturer. They do not recommend max load but the proper pressure for the true distributed loads. I have actually weighed my fully loaded RV front axle, back axle, left, right and total. I have a 24' RV (also known as 'small') and I am 1000 lbs under weight so it would not be unusual to have lower pressure required than a max loaded 32' ocean liner.

I got some good ideas here. I don't understand the dual fill system that was mentioned but I am going to read up on that. I am not sold on extenders. If you read my original post closely you will see that I already have an extender failure. The guys at Les Schwab are real down on them. This issue comes down to the tool, the outer tire valve stem, and the wheel openings. The angle isn't there. I have two different tools. It is like I need to cut a 1/4" to 1/2" notch in the wheel access hole so I can seat the tool properly on the stem. I cannot get it to stop spitting air.

Bentspoon

[chroniekon]

I replaced my inner dual stems with solid ones that are long enough to extend through the hand hole of the outer dual. The tire has to be broken down from the rim because they bolt in from the inside of the rim. I found them here:

Dually valve kits for Motor-homes, Busses and 6-wheeled chassis

I didn't need a 'kit' for all the wheels, so I called them and they were able to sell me just the stems I needed.

[Bentspoon]

I am looking at the Crossfire dual tire fill system by Dual Dynamics. Lots of good reviews. Very convenient. I think I may go this way. The only drawback I can see is that they don't have a bracket for my wheels but it seems easily remedied.
Bentspoon

[Delco Bobby]

I think it was mentioned already in this thread.

Go to duallyvalve.com

They are real valves, not extensions.

[A32Deuce]

I have had solid extenders on mine for over 70000 miles and never had a problem with them.

[Wolverine 1945]

Originally Posted by A32Deuce

I have had solid extenders on mine for over 70000 miles and never had a problem with them.

I am sure the solid ones are much easier to deal with than the flexible ones,,,
I don't have much trouble any more since I learned to hold with pliers,,, only thing is you cant use all types of air chucks,,, because you only have one other hand,,, unless DW is helpful !!!

[BamaBob]

Originally Posted by Wolverine 1945

I think Deuce is right on !!!
I have found the only way I have any luck adding or checking air in the inside dully is to to hold flexible extender with a pair of needle nose pliers !!!
It would also be very helpful to have 3 hands !!!

Or metal valve stems...may want to look into replacing rubber valve stems with the metal ones.

Originally Posted by A32Deuce

You don't have a tire sticker at the drivers door? I like going with the manufactures recommended pressure and maybe go higher but never lower.

Good Rule of thumb, but you should go on load rating PSI based on CAT scale weights of each axle (for Ex, my sticker says 120PSI front Axle, CAT Scale calculation is 110PSI - 10PSI makes a WORLD of difference in the ride )

[Joe_GA]

I've had flexible extenders on my dually truck for over 20,000 miles and never had a problem.

[A32Deuce]

I was told not to use rubber valve stems. I have all metal on the MH and car trailer including spare tires for both.

[Wolverine 1945]

I would think that running the tires as low as 60,,, might cause them to run HOT ???