[Richard and Rhonda]

Just wanted to throw in my .02 with a warning. The air bags should be sized for the weight they are carrying. It's pretty simple math. If you take the diameter of the bag and convert to square inches and then multiply that by the air pressure in psi you have the carrying capacity of the bag. For example a 6 inch diameter bag would be about 28.3 square inches in surface area. So if you multiply 28.3 times 90 psi that bag would support 2545 pounds.

I walked through that to make this point. It very well could be that different length coaches were speced with different air bags. It could be a bad assumption to take part numbers from one length coach and assume they are the proper bags for another length coach. Slides and no slides would also call for different bags.

The air bag diameter can have a huge impact on how the coach handles. Let's take the example above. If we decrease the air bag to 5.5 inches in diameter, it would take 107 psi to support the same weight. If we increase the bag to 6.5 inches in diameter, it would take 77 psi to support the same weight.

What this means is the spring rate gets much stiffer as the air bag diameter decreases. Remember we do not control the pressure in the air bags, the ride height valve adds or lets out air until the coach reaches the set height. Of course if the air bag is really too small the valve can't apply more pressure than is in the air line to lift the coach.

Bottom line smaller bags equal stiffer ride, bigger bags softer ride.

Sorry to get all geeky on you, but I didn't want someone to post air bag numbers, and someone else to stock up on perhaps the wrong air bag.

Of course Paul knows about a million times as much as I about spring rates, so I'll shut up now.