Electric brake drums - how to correct out of balance

[em1942]

Having trouble with tires on my tandem and noticed the drums are way out of balance as they rotate rather quickly with the heavy side down when the tire is removed. There isn't any area on the drum to drill for balancing. The center hub is steel and about 6" dia x 1/2" thick that the drum is pressed onto. I could turn a steel balancing weight in a lathe and then cut/weld to the center hub but it would take a lot of weight since it would only be 3" off center. There should be an easier way to do this. Any suggestions?

[Lynnmor]

I've been harping on this subject for a long time. The drums are NOT balanced from the factory and there is little point in balancing wheels under this condition. Buying new drums is a crapshoot because they may be even worse than the ones you are replacing. The OP is the first person that has come on here having actually tested the balance of the drums.

OP, you are correct that there is no provision for balancing. What I do is clean out ALL the grease from the bearings, add a few drops of light oil, and find the heavy spot. Then mount the tire/wheel with the heavy spot opposite the drum heavy spot. Mark everything and add balance weights to the wheel till it comes into balance. Clean the bearings, pack grease and reassemble with a new grease seal. Using this procedure, you should be able to get the entire assemblies within 1/2 oz. If you just balance the tire, you could be out 6 oz. or more.

[RJsfishin]

If you sure its the drum out of balance so bad that it rotates against the resistence of the bearings, grease, etc, its junk, right from the get go !

[K_Charles]

Buy a new one, and find out what's wrong with the rest of it, bearings seal and brakes should not let the drum turn by itself if off the ground with no wheel.

[eHoefler]

They come already balanced. Your method of checking for balance is not a good way to judge it. There is a lot more affecting it when installed. The brakes could be dragging, the magnet is dragging, the bearings, the wheel seal, the brake dust in the drum, drum warped from heat, grease packed in the hub, etc..

[1492]

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