Dealing with Duals. Tire pressure.

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NickD

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#1
The 82 Pace Arrow is my very first vehicle with duals and kind of appreciate the importance of proper air pressure.

First problem is access, with the huge drums and rotor, only access is from the outside, rims have hub caps, they have to be removed first. The rims have four oval holes I can barely get my hand in, matter of fact and slip it in, but have a heck of a time getting my hand back out. Has ten lug nuts so possible to put those heavy tires on completely blocking the inside tire valve.

The inside tire valve faces out, the outside tire valve faces in, a standard 2" right angle air chuck is useless, can get at the outer tire with a standard 4 1/2 inch air chuck, but the angle is too great to reach the inside valve, plus the stem is too short to reach that. I solved that problem but cutting 1/8" pipe threads on 3/8" tubing and bending the tubing in such a way to get a straight shot at the inside tire with the valve facing out.

Any kind of standard tire gauge, I looked, but maybe at not the right stores, and couldn't find anything off the shelve that would work. So I attached a two foot air hose to a 100 PSI gauge with the extended air chuck on it to reach the inside tire. Got me wondering how other people check air pressure in these things. Is there something on the market or do they have to make something to fill and check the air pressure?

At several RV stores, looked at these tire valve extenders and had more questions than answers, would I be adding leaks to the tires is my first question, then what about tire balance, these things are heavy. The inside tire with a straight shot seems almost feasible and could tighten the extender with the outside tire off, but would play hell trying to hold that hose trying to get the outside tire back on again. And how could I make a sharp U-turn in that small space for the outside tire with the valve facing in? Would still have to pop off the hubcap to check tires.

Ha, like to think I am clever, but this one has me beat, how do other people deal with duals with a simple matter of checking tire pressure and filling them? Hear that truckers use a hammer for the proper thud sound, but doesn't sound very accurate. It is easy to check the tires off the vehicle, but a rather time consuming process, especially when on the road. Lugs are torqued at 150 pounds times 40 lug nuts, that could wear an old man out.
 

WallysTrucks

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#2
I would go to a tire shop that deals in truck tires and have them check your tire pressure. then copy what they use. I have used a duel position fill check with a hose and gage attached this gives you access to both inside and outside stems. Our tool store will have this when it gets open again.
Wally
 
N

NickD

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#3
5 out of my 6 tires only lost between 10-15 PSI over the winter months, not bad I figure, one dual was down to zero. Called an RV dealer and was quoted shop labor rates to repair it, called my regular tire guy, could handle it, but just bring the tire in. Was a bead leak, he cleaned the rim, put a sealer on it, couldn't align the mark with the valve stem so rebalanced it, all for five bucks. Very easy to check pressures with the tires off.

I have no problem at home with my 150 PSI air compressor and home made tools, but was concerned about the road, course today, it's almost impossible to find a gas station with air and then how to hook up my home made stuff. Do have my AAA card and not worry about it, but also have plenty of 12 volts and 120 VAC, maybe will shop around for a small air compressor and DIM, ha, do it myself.

Just seems to be a common problem for anyone with duals, but even the front tires have the stems facing in. Ha, wonder if truckers even worry about it, the interstate is loaded with tire threads that overheated and fell off, but don't want to join that crowd.

I held and stared at these extension kits and my mind goes blank wondering about hooking the inner tire to the outside hub, getting my hand in there, balance, and the problems a guy would have if he has to remove a tire, more crap in the way, and the torque on my hub bolts is around 250 foot pounds, not something I would want to fool around with on the road.
 
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#4
Nick, I don't know how you're experimented you are with RV, but if you drive on interstate at speed, make sure those tire are wiith in their life span, less then 5 years old or they could blow at any time, more if they got any repair(even a plug). In case: Tire under RV rot away because not enough use, they collect moisture by sitting, don't get warm regulary, the cord rot, rubber crack, if had a repair moisture get in quicker when it cool off. Those vehicule are builted with tootpicks, if a tire blow, usely it take the fender or part with it. If the pressure go down, air may seep trough micro crack( a bit like an old AC hose). You probably got 19.5" rim on P32 chassis? To service those rim you need a dual headed chuck on the air hose like MILTON 690.
wrench
 
N

NickD

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#5
Thanks for the advice and warnings, tires are only a year old now, but that one rim wasn't cleaned very well.

This is my second RV and did have a blow out with the first with brand new Firestones, needless to say, was the last Firestone I have ever purchased, was scary, but managed to keep control until the vehicle was safely stopped.

You can see I am concerned about proper inflation, just seems like there should be an easier way on the road, maybe truck stops have the correct air chucks, do have that Milton, but still had to extend the tube to fit the inside tire, quite a long reach.
 
N

NickD

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#7
Found over a dozen different inflators as they call these extension hoses and even held some in my hand. With the recent tire repair, my guy rebalanced the wheel and added a one ounce weight to one side. Ha, said with a tire like this, does that make a difference? He said I would noticed it. These inflators weigh a ton compared to that weight. Thought about mounting the valves 180* apart to counterbalance, but the inner inflator weighs a ton more than the outer. So still have this question about tire balance with these things.

Some inflators mount in the hole in the rim, some to the hub, others, you drill a hole in the hubcap, but nothing said about affecting the tire balance. Maybe tire balance is not that important, wheel spins at about 500 rpm at 60 mpg that isn't very fast. But the inflators are at the same diameter as that one wheel weight. Am I making mountains out of molehills with tire balance?

Anyway for the price of a pack of four of these inflators, can buy a 120VAC one or two gallon air compressor, 150 PSI, 2 cfm, and only God knows at what pressure. Do have a generator and my home made tools and plenty of places to store these small air compressors and plenty of places to store it in the motorhome.

I looked up four popular types on the web for reviews, each had just about as many positive reviews as the best air compressor in the world to the worse piece of junk I have ever purchased. Big help as to which one to buy, may just drop all four names in a hat and buy the last one I pull, with my luck, always works out that way.
 
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#8
Nick, One thing to keep in mind with your weight comparatives. The location of the weight in relation of the center of the tire. The further you get away from that center the more effect of the weight.
I have installed that type of extenders on many trucks. Mostly tool type trucks and RVs, I have never heard a complaint yet. Heck, they probably had some engineer design them. So they got to be perfect.
 
N

NickD

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#9
Balance, or out of balance was my only question with these inflators/extenders, was my tire guy trying to be cute by tacking on a one ounce weight? True, these tires spin way slower than a car tire at the same speed and believe that vibration increases at the square of rpm, too lazy this morning to get my book and look up the equation. Also the ratio of the extender weight to the weight of the tire, in that respect, the extender weight would be many decimal points away, almost insignificant.

But if you are putting many of these on without tire vibration complaints and without rebalancing, it must not be a problem, thanks.
 
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#10
All I was trying to point out Nick, is one ounce of weight won't match the extension(if the extension is one once) because of the distance of the two in relation to the center line.
I tried balancing a set of 44" mud tires on a 15" rims. Because of the location of the weights on the small rims compared to the big tires it would have taken pounds of weights to balance. But with a tire groover, it took very little rubber removal from between the treads to balance.
All I am trying to say is your tire guy can't put one once of weight across from the extension and claim it to be balanced. And the closer your able to mount the extension to the centerline the less effect it will cause.
 
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NickD

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#11
Well Mike, all this stuff is new to me, was in 1965 I was in a Sears store and saw this 2 HP 150 PSI, 8 cfm air compressor on half price sale, regular price back then was $350.00, there is sat asking me to buy it for $175.00, still have it, never had problems with it, even sand blasted a ton of parts when I was restoring my Model A and have purchase a bunch of air stuff for it. Neighbors are always coming over to fill their tires. I feel my air compressor is a zillion hp today by the new standards.

So I bring home this motorhome with duals and can't even check nor fill, mainly the inner tires. My Milton double chuck wasn't long enough to reach the inside tire, looked around to buy stuff, couldn't find anything so down to my shop to make stuff. This is crazy, buy a vehicle and can't even check the tire pressure. I am okay at home, but was concerned about being on the road. Do truck stops have the means to check tire pressure? Maybe it's not even a problem.

Ha, was driving my kid's car in the next town with a low front tire with the steering wheel pulling to the left, had to stop at six self service gas stations to finally find one that had air. Then I had to stop in and get change for a buck as I needed 50 cents to turn the darn thing on. And had to guess at that as the darn thing didn't even have a pressure gauge. Just wonder what other people do to check even conventional tires.

When my AT hose popped on an interstate, I did pull over as far as I could leaving three feet from the main road, darn trucks were playing a game and missing me by a foot rocking my family. No way in hell would I change a flat tire on the interstate, AAA card will take care of that, would be suicide.

Didn't think that checking tire pressures was such a problem.
 
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#12
Nick, checking the air pressure on those smaller dual wheels can be a pain if not set up correctly. I have many different air chucks in my shop in the search of the magical one that will make the job easy.
I have installed lot of the extensions you mentioned. I like the braided versions better the the plain rubber hose versions.
To me the situation starts with the guy who put the valve stems in the rims to begin with. There are several versions of tire stems, different lengths and angles. A one stem fits all don't make it easier to check the tires. But does make it easier to rotate tires. But with the proper stem installed the tire can be spun on the balance machine and put your mind at ease. Then the next problem we run into is the guy putting the tires on. He either don't know to align the holes, or they align the holes but also align the stems, reducing the working room.

So if balanceing is a concern because of added fixtures, I would suggest visiting your local tire shop and showing him your issue. Ask if he can put a different style stem in your rims to help the situation. Of course the stem in the outer rim would be different then the inner. So when and if the time was to come you felt you wanted to rotate your rubber, the tires may have to be dismounted to move into a location of your choosing.

Now if your looking for as easy way, and go along with so many others who have felt the extra hardware is not a balance concern. You know about the extensions already. But there is even another way. Cats eyes. This device will allow you to walk around your rig and visually see right away if you have a tire down on the duals. With proper pressure in both tires, the eye will be closed, but if a tire gets low, the eye will open.
The are other tire monitor devices too, valve stem caps that willl warn you, as well as electronic devices.

I had to deal with a customer,
So about this idea Nick, get the right stems installed, and install a set of these,
http://www.accupressurecaps.com/?s_kwcid=tire%20monitors|766738159&gclid=CN7I0cyqvYsCFSAMIgodOxTPww