All Airstream 32 foot and larger motorhomes use an additional rear axle, that's called a “tag axle”. A tag axle is never a part of a drive line, but is a very important part of the rear end weight carrying capacity of the motorhome. Added to the drive axle are two air bags that govern how much weight the tag axle carries. The greater the rear end weight, the greater the air pressure that is automatically added to the air bags  The tag axle and air bags work together to keep the motorhome chassis level, which also varies the amount of weight that the tag axle will carry. The air bags use a high quality rubber, but rubber anything, has a life that varies with usage and temperature exposure. Anything made with  rubber must be exercised to stay alive. If the air bags are used frequently, they will last about 25 years. However, if they are seldom used or not used at all for a couple of years, their life can decrease to two to three years. The same is true regarding the rubber rods that are in all torsion axles.


Statistics show that the life of frequently used torsion axles is 25 years. But if the rubber rods within the torsion axles, are not used (exercised) reasonably often,  they will solidify or become very soft. In either case, the axle becomes useless, which causes the air bags to inflate to their maximum pressure, which usually results in one of the air bags to rupture, which then overloads the tag axle.


It's extremely important that the tag axle serves it's designed use, if not, many other costly problems can and will occur.


The following tag axle test procedure, is easy to do and will show if it is still serviceable or not.

  1. 1.Pull the drive axle up on some 2 by 6's so that the tag axle tires will be off the ground. 

  2. 2.In doing so, the tag axle tires should drop about 3 inches. If so, the axle is still good. 

  3. 3.If the tag axle tires do not drop about 3 inches, the rubber rods have become useless and the axle must be replaced. 

  4. 4.Replacing the tag axle is not a difficult task. 

  5. 5.When replacing the tag axle the air bags should also be replaced because of age. 


As of October 2016, tag axles are only available for the Chevy chassis. They are available complete except for the 10 lug drums. The 10 lug drums are no longer available and must be replaced with 8 lug drums.