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IT'S ALL IN THE BALANCE.
By - Rob Bradford
These articles are provided for your personal use - Copyright remains with Rob Bradford
NOT to be reproduced or copied without the express permission of the Author

Everyone likes to live a balanced life, particularly when one is wearing spoked wheels wire wheels like our good TR friends.
What we need is the pleasure of driving wire wheeled TRs which do not vibrate our lunch into foam with the potential for most unsavoury outcomes.

The trouble it seems is finding someone who can properly balance a wire wheel on the balancing machines that are now almost universally used.

Most modern balancing machines use a spring loaded Cone to centre the wheel, which is then clamped hard against a flat flange and thus relies on the wheel having a flat & true surface on the back in order to get the wheel running true on the balancing machine spindle.

Our spoked wheels do not have any true and flat surfaces on the back, they use a female and male cone arrangement which is incompatible with the balancing machines and leads to constant issues with accuracy.

An ideal solution would be to produce an inexpensive adaptor so that our spoked wheels
can be balanced and provide a uniform result for every balancing operation.

There is no doubt many a defunct worn out splined adaptor languishes in sheds around the country. They are just itching to become loved once more!
These old unloved items have the potential to be easily turned into the very item to avert the foamy lunch for ever.

Take a hacksaw and cut the end off a worn out adaptor at the thread which leaves a handy amount to grip in a small lathe.


Fear not the revelation that the adaptor appears to be offset or wonky when you have cut it off and look down the end, as this is not the important bit. The photo below shows that the wall thicknesses may not be uniform - this does not matter.
What is important is that the flange is now going to be the main reference as this will be clamped to the driving face of the balancing machine and the assembly has to be centred.

The critical issue is to:

  • make the inner conical surface concentric with the outer conical surface (where the wheel sits)
  • and to make the flat rear surface perpendicular (at right angles) to the outer conical surface (as in the photo below)

In some cases our adaptors are reasonable however it is necessary to put the adaptors in a lathe and trim the back to make sure.

This is so that the cone on the balancing machine can always centre the adaptor accurately.

Note that the above photo shows what you or the machinist needs to achieve. I used a dial gauge to make sure the flange ran true and then set the dial gauge onto the other side against the cone face to make sure that also ran true (you may need to juggle a compromise, about 0.002” seemed to good enough).

The inner conical section is then machined in the lathe so that it looks like the photos below:

This is what it looks like with the adaptor fitted to a wheel.

This is the adaptor fitted to the balancing machine.

This adaptor cost $20.00 for machining and when tested on the digital balancing machine proved to run spot on.

I am confident that I will get much better results from now on, as I will have all my wheels balanced using my own adaptor.

Rob Bradford.