Blaine found a set of NOS Perfect Circle hubs, which look to be private-labeled versions of the Selectro hub manufactured by Dualmatic. Unfamilar with Perfect Circle, I wondered why the company would private label a set of hubs.

It turns out that Perfect Circle had been a leader in the development of piston rings for several decades. In 1963, the company was purchased by the Dana Corporation. It’s possible that relationship led to the private labeling of the hubs. (Read the whole Perfect Circle history here)

These particular hubs should fit the Dana 27 axles, as that was the standard axle on early Scouts (but I’m not expert on the Scouts).

We’ve seen the above hubs branded under multiple names, including Dualmatic, Selectro, Perfect Circle, Free-Lock, and others. But, where did the hubs originate?

Unfortunately, as this point I only have theories rather than actual answers. One theory is that they were developed by Free-Lock, but not patented, prior to Free-Lock’s demise. Somehow, Dualamatic/Husky ended up with the hubs (probably purchased Free-Lock’s assets) and then Dualmatic manufacturing them under the Free-Lock brand, then other brands.

My second theory is that the hub is based on this hub patent from Clark Peterson in 1955.

It has the spring system and It appears the entire top of the hub twists. But, there are some differences. The central bolt does not exist to hold the hub in place, instead side bolds secure the top. Maybe someone who has a set of these hubs can compare it to the hub design above? Below is a schematic of a Dualmatic hub for comparison.