Originally Posted by Phantom
What shops can balance the running gear... en total? I assume this means spinning the wheels, tires, drums, etc. when they are on the trailer. 'Not just balancing the tires'. Does a tire shop do this?... RV dealers?
Spinning tires on an Airstream is very dangereous. Because of the large amount of unbalance that can be present, the counter-balancing dish, can sling off.
Many years ago, a number of Airstream dealers had the Snap On balancer, as seen in the following.
Wheel Balancing Photos - Inland RV
Unfortunately, most of those dealers are gone, and that balancer is no longer available from Snap On Tools.
That system uses 2 weights, placed 120 degrees apart on the wheel. Each weight, including the heavy spot affects 150 degrees of the circumference of the wheel or assembly, which overlaps. That system, when done properly, results in a balance that lasts at least 10,000 miles, sliding tires excluded, which is the mileage that the bearings should be repacked, as well. A single weight counter-balance as per Snap On, is only good for about 3000 miles, at best, and then must be moved to a different location on the wheel, when the balancing falters, even though many times, the required amount of weight, remained the same.
The older Airstream trailers had 3 piece hub and drums. They are notoriously out of balance, normally 8 to 10 ounces on up to 3 pounds. You can look at the castings, and see that the machining was not anywhere near the center, as one side of the drum brake surface was as much as 1/4 inch thicker, than the other side. Not good.
The next style hub and drum, was 2 piece. That was an improvement, but the basic out of balance issue. still existed, but not as bad.
The newest style hub and drum, is "unicast". It's a one piece casting, that is machined for the bearings, and brakes, along with the armature plate, which is the surface that the brake magnet faces.
The "unicast" hub and drum, is a huge step in the right direction, but is still not balanced as they are in the automotive industry.
Technology, came up to bat, and developed the dish type "automatic balancers" that simply, slide over the lug studs and is covered up and held in place when the wheel is mounted. The manufacturers say that from 25 to 30 miles per hour, the running gear becomes automatically balanced.
The end result of all of this, is that the trailer owner, can now keep the running gear properly balanced, by first having the tire and wheel balanced, and then adding the after market balancers, that are readily available, from many sources.
As time goes on, that system should keep the "balancing issue" completely out of the picture as a necessary periodic thing that must be done. When it's time for new tires, have them simply balanced on the wheel, mount the wheels, and it's done, giving you the peace of mind that the vibrations caused by lack of proper running gear balance, is forever gone.
No more chasing down a place that can balance the complete running gear.
The only draw back???
You still should repack the bearings and check the brakes, once a year or 10,000 miles, which ever comes first, regardless of what type brakes the trailer has. This holds true for electric brakes, self adjusting electric brakes, and disc brakes.
Finally, a solution to a problem that's been going on for half a century.