Make your own hypercracker

A commercially made hypercracker is now available, see:

See also how to improvise a chain whip

WARNING - If the lock ring is tight this tool will bend your dropout!

Like this:

The Hypercracker is a tool for removing the lock-ring that secures Shimano cassette sprockets.  This is necessary if a spoke breaks on the cassette side of the rear wheel, or if the freehub needs to be removed for maintenance.  The 'official' tools for the job are a Shimano cassette lock-ring remover, a big spanner and a chain whip - not the most practical toolset for an extended tour!

Hypercrackers were invented by Pamir Engineering, who used to make them.  Sadly they no longer do, indeed I think the company was wound up when its founder retired.  To use a Hypercracker you remove the rear wheel and fit the Hypercracker into the spline of the lock-ring.  Then you replace the rear wheel in such a way that the frame or dropout prevents the Hypercracker rotating.  All it takes then is a pull on the pedals (by hand should be sufficient) which rotates the cassette and rear wheel while the Hypercracker and lock-ring remain stationary.  Voila! the lock-ring is loosened and when you remove the wheel from the bike you will be able to unscrew the lock-ring by hand and remove the cassette.

I first saw the idea of making your own Hypercracker on another cycle touring website: Ed and Jeanne Downing'sTheir version involves some welding which mine doesn't, but then mine puts more load on the dropout and I did bend Juliette's dropout trying to release a very tight lock ring. I was not popular until it had been hammered and bent back into shape!

I took a standard Shimano cassette lock-ring remover and ground most of it away so this much was left:

The stub sits against the dropout.  I should think that if the lock-ring was really tight there is a risk of bending the dropout.  It fits onto the lock-ring like this:

In use it looks like this:


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