<VV> Unbalanced wheel ?...no !

[Daniel Monasterio]

As a part of the restoration of the Bluebrier, got new tires and got them balanced but, on the trip to Denver's convention, noticed vibration on the right rear wheel just over 60mph so, kept the speed at no more than 60mph all the time which was (I think) good for the engine (still breaking it) and for safety.
As I am planning a trip, next weekend, I went to the tire shop to check that wheel balance but, the machine said it was ok so, as there are not any more old fashioned tools for wheels balancing (the kind where tires are checked on the vehicle), came back to the cave to start working on the problem.
1st, jacked up the offending tire, removed it and installed the front right tire which I knew is well balanced.2nd, started engine, put in drive and accelerated..... same vibration so, the wheel & tire assembly was not guilty.3rd, removed tire, put nuts to hold the brake drum and repeat testing..... same vibration.4th, removed drum, repeated testing procedure and... no vibration.5th, inspected drum and, it is not GM but Century brand without any weight welded as always seen on GM drums.6th, got a used GM drum and tested with tire in place and... eureka !!, no more vibration.
This the first time in 43 years dealing with Corvairs that I found this kind of problem.
By now, the Bluebrier is better tuned and ready for traveling again.
Saludos
Daniel Monasterio