Chain whips on the market can be classified into ones:
- suitable for 1/8"-wide (fixed-gear) chains, such as Park Tool SR-18.2,
- suitable for 7, 8, 9, 10, 11?, 12? sprockets,
- suitable for 7-11 sprockets, such as Shimano's Pro PRTL0084,
- suitable for 7-12 sprockets, such as Park Tool SR-12.2, and
- suitable for 6-13 sprockets, such as Pedro's Pro Chain Whip.
Yet both amateur and pro mechanics report that the fixed-gear variety works just fine for all sprockets. This makes sense, if the main difference between a fixed-gear chain and a 12/13-sprocket chain is mainly the length of the pins, with minimal difference in the thickness of the side plates, then a fixed-gear chain can be used. It is just that the torque will be offset, applying forces outside the plane of the cog. Out-of-plane forces on a cog should be of no concern. They would be no different than someone trying to switch gears while climbing—when the chain will also pull on a cog out of its plane. It's not ideal, but within working tolerances.
Why are there so many varieties of chain whips when a fixed-gear chain whip works for all styles?
Is it only that the chain whip wraps well around just the smaller cogs, where a wider chain wouldn't fit, but does not quite hold leverage around largers cogs, where it would fit, albeit askew?