Dick,
Please consider giving good ol' boy, Dale Fenton a call at Trailair for your own satisfaction and the enlightenment of all of us following this thread. He is the inventor and he is accessible. Try this number: (800) 998-4238. Circle back here to post Mr. Fenton's wisdom.
In the mean time, here are the FAQs from the Trailair website:
Air Pin
FAQ / Things To Know
Q. Do I need an air compressor? How do I fill it with air?
A. An air compressor is not required but is certainly a recommended item to have if you are going to use an air ride product. If your truck does not already have air onboard, most any portable air compressor designed to fill a truck tire will work great as long as it can produce air pressure from 80psi to 120psi depending on the hitch needed and the coach you're pulling. A standard tire fill valve is used on the topside of the air spring to fill it with air so it is just like filling a tire.
Q. How much air does it take?
A. A combination of things affect the amount of air needed such as; the size of the air spring in diameter and height, the pin weight of the coach, the mechanics of the individual hitch, altitude and ambient temperature. Air pressures can range from 20 psi to 120 psi depending on the aforementioned items. The air ride pin box is to be maintained at a predetermined ride height found on the system. We want you to maintain the ride height, not the air pressure. With the truck and trailer coupled, at rest and on level ground, you should have enough air in the bag to open the jaw to a point that the bottom lip of the top shroud on the shock absorber is even with the arrows on the decal that is affixed to the lower body of the shock absorber.
Q. How much does the hitch move up and down in tow?
A. The unique scissor action of the air ride pin box is designed to travel up 1" and down 1" at the king pin for 2" of total travel. At the front of the pin box, the travel is about 1 ½" up and down for a total of 3" travel.
Q. What happens if air bag loses air?
A. If the system loses air, troubleshooting is easy because it can be only one of three things; the air spring fitting, the fill valve or the air spring itself. First thing to check is the seal of the air spring fitting to make sure it is sealed by simply pouring water on the area. If it bubbles, pull the fitting out, re-coat it with Teflon tape or standard pipe fitters dope and re-install (torque it to 20 ft./lbs). Next item to check is the fill valve by spraying soapy water on the area with the cap removed. If it bubbles, replace the fill valve core by simply sticking the topside of the cap onto the valve core and spinning counter clockwise to remove it. It can be found at most auto parts stores or by contacting Trailair. If the first two are not leaking then the air spring is not holding air and a replacement should be obtained directly from Trailair.
Q. Can I pull my fifth wheel coach without air in the air spring?
A. Absolutely!! Every Trailair air ride pin box design comes equipped with mechanical stops that insure the air spring, shock absorber or other components will be properly maintained in the event of an air failure. In the event the coach is pulled without any air, the ride quality will revert to the quality you had with the standard pin box that you replaced.
Q. How much will it extend my pin?
A. That depends on the pin box being replaced. Many of the advertisements and articles show our extended pin box because it was the first air ride pin box we unveiled. If you match your replacement style to a Trailair pin box, the pin would not extend more than about 5 inches and in many cases, it will be the same.
Q. Is the air spring and shock absorber an off the shelf item?
A. Either Goodyear or Firestone makes the air springs and are standard air springs found in most of their industrial catalogs. Either Monroe or Sachs Automotive Co makes the shock absorbers for Trailair. Both companies use standard shock components but both have special internal valving suited specifically for the needs of Trailair. Suitable replacements may be obtained through authorized Trailair dealers or directly from Trailair.
Q. How do I hook and unhook from my truck?
A. When hooking and unhooking, the main thing to keep in mind is to not over compensate for the oscillation of the lower jaw. You should hook and unhook without changing the air in the air spring. When unhooking from the trailer you can avoid "high pinning" by raising your coach just enough to take most of the weight off of the truck (even though the lower jaw is pushing down, you can take most of the weight off the truck). A good indicator of when the weight is off the truck is when the king pin plate on the lower jaw of the Trailair air ride pin box is parallel to the ground. At that point, then unlock the fifth wheel hitch and pull out. Sometimes you have to "pop" the jaws of your fifth wheel loose if they are in a bind by putting your truck in forward or reverse and stepping on the brake just enough to dislodge the jaw mechanism in your fifth wheel hitch. Be careful to not damage your landing gear on your coach.
When you reconnect the truck to the fifth wheel, the lower jaw will be down approximately 1 1/2" in the front. The Trailair lower jaw is built with a front lip that will allow your fifth wheel to push against it as you back the truck under the trailer. Simply line up the pin and back under the trailer, the truck will push the lower jaw out of the way and the king pin will snap into the fifth wheel. Be sure to lock your fifth wheel and attach your safety brake cable as well as connect your electrical cable before you travel.
Q. Can I use my tri-pod with this air ride pin box?
A. Yes. You may find, depending on the construction of your tri-pod, that you will have to raise your coach about 1 ½" after you have disconnected from the truck so that the tri-pod will slip under the kingpin. Once the tri-pod is in place, simply lower the coach down onto the tri-pod, thus transferring the weight to it. To remove the tri-pod, lift the coach up high enough to remove it. Remember to let the king pin back down that 1 ½" for reconnecting to the truck so that you do not "high pin" when connecting to the fifth wheel hitch.
Q. Which will benefit most, the truck or the trailer?
A. In most cases, the largest benefit will be seen or felt by the fifth wheel coach. The ability of the Trailair air ride pin box to absorb road shock and stresses from the truck and trailer battling each other is unsurpassed. The dampening effect will reduce trailer frame flex, stress to the outer skin and also to the interior amenities. In most cases, a dramatic benefit in ride quality is felt in the truck as well. In a small percentage of cases, little or no benefit is felt in the truck. If that happens to be the case, many times Trailair can make the performance better with different air bags or shock absorbers. Simply call a Trailair technician for assistance if you're having this experience.
Q. Does the size of the truck effect the performance?
A. It can. An undersized truck suspension or underpowered truck can have an adverse effect on the ride quality when pulling a fifth wheel coach. Always make sure you are operating within the recommended practices of the manufacturer of both the tow vehicle and the Fifth wheel coach.
Q. Does tire inflation have an effect?
A. Absolutely!! First, an under inflated tire is dangerous and anyone towing should make sure that all tires meet the requirements for load and inflation as set forth by the tire manufacturer used on both the truck and the trailer. Having said that, Trailair highly recommends using a tire inflation chart that can be obtained from most tire manufactures or from the Tire and Rim Association, Inc. It is clear that an OVER-inflated tire can adversely affect the ride quality of a rig, sometimes dramatically. For example, a common tire used in light truck is the 235/85R/16 load range E tire. Most makes of tires allow for a single tire to be loaded to 3042 pounds at 80psi. Many manufactures of this size tire allow for it also to be at less air pressure when seeing less weight. In the case of this tire if the load bourn by the tire is 2400 pounds, it may be acceptable to run it at 60psi. By simply knowing the weights of all axles, both loaded and empty, and using recommended practices, your tires can be operated within safe ranges that will allow you to carry the load properly and safely, but also enjoy the softest ride possible. Also be sure that you have the correct air pressure for the weight when connected to your trailer. Consult your tire manufacturer or dealer for Light Truck Load & Inflation tables from the Tire and Rim Association, Inc for the make and model tire.
Q. Will the air ride pin box work with various rear trailer suspensions?
A. Yes. The simple rule is that the better quality the rear suspension, the less affect the air ride pin box will have on overall ride quality. However, the important thing to keep in mind is that even with the very best possible rear suspension (Of course we are partial to the Trailair RV-Series rear air ride suspension), the battle between the truck and the coach still remains and the air ride pin box will certainly reduce the effects of that battle.
I really don't know about going down the road Dick I can't see the arrows on mine. I agree with all the other stuff, I do about the same thing. I don't know how it can change the level,the pin weight makes the tri-glide part work. I"m not sure how the arrows would show other than the air pressure rising in the air bag while underway from the hitch going up and down. Will be interesting to see the comments.
