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It is sad to lose the interchangeability that formerly existed, but these hubs work so well that they have come to represent the new "standard." If you're not sure whether your bike has a cassette Freehub or a thread-on freewheel, Due to the location of the bearings in most Shimano Freehubs, the axle is supported closer to the ends.As a result, bent axles are rarely a problem with these hubs.A special tool is available to remove and retighten the lockring on the road, using the bicycle's frame and chain to provide leverage.
This allowed any brand of freewheel to be mounted on any brand of hub.
The lockring has a normal right-hand thread: turn clockwise to tighten it.
To remove the lockring, you need to turn it counterclockwise, but then the cassette will freewheel, so you need a chain whip to hold the cassette.
The Freehub incorporates the ratchet mechanism into the hub body (although the ratchet mechanism is still replaceable).
When you wear out the sprockets on a Freehub, you replace the sprockets only, not the ratchet mechanism (which typically lasts much longer than the sprockets).After replacing the cassette, the lockring should be tightened until it is snug, but not tightened with gorilla-like force -- especially not if it may have to be removed on the road.