[Fulltiming]

The tag axle does contribute to straight line stability in a coach. I do not have a steerable or liftable tag and my tag tires don't seem to wear any faster than the other tires. If it feels good, as with Tom, balance them. If you have a problem, try balancing them. Otherwise, as Tom mentioned, the default at the commercial truck tire shop will be to NOT balance them. Another thing to watch out for is valve stems. Commercial trucks drive lots of miles so they go through tires much faster than motorhomes which typically have their tires get old and crack before the thread is gone. If you don't specifically ask, a commercial truck tire shop will not change the valve stems. This is NOT good for motorhomes use. I now request new valve stems any time I change tires as I have had the old valve stems start to leak air after a tire change when I didn't ask for new stems and that means another trip back to the tire shop, dismounting the wheel, breaking the seal with the wheel and changing the stem out, remounting the tire, remounting the wheel. Big job, big pain.