[FC] Unbalanced wheel ?...no !

[Andy .]

A few thoughts... My local preferred tire guy has a machine that he can high speed balance on the car and true the tire - actually shave down any high spots (as installed on the axle) making the tire perfectly round.  A round tire balances much easier!
 
You didn't mention whether you had both rear wheels off the ground for this or just the one.  I guess you could just have the one off if you don't have a posi.  My thought was that if you had both off the ground and slid on the GM test drum - if it was a tight fit (Slighty smaller ID or rusty), it would be possible that it would not spin at all - just the other side... non test side.   And if you were doing this alone sitting in the cab you would not be able to see the right rear without a mirror.  Of course a static drum will not vibrate.
 
Not saying that a drum can't be out of balance - it's just that they are fairly close to the axis (compared to a tire) to cause a lot of vibration.
 
So did you actually drive it with the spare drum and the vibration was gone?  If so, that's great!
 
Send the out of balance drum to Corvantic member Andrew S.  He is starting a collection of crappy aftermarket brake drums.  :)
 
Andy
 

 

> From: dmonasterio at hotmail.com
> To: corvanatics at corvair.org; virtualvairs at corvair.org
> Date: Tue, 22 Nov 2011 13:23:58 -0800
> Subject: [FC] Unbalanced wheel ?...no !
> 
> 
> 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
> 
> 
> 
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