pull it onto the new cog. The cassettes are designed so that the windows are staggered, ie. the
windows on adjacent cogs are located so that the chain can come off one cog and move directly
onto the other. This makes for much faster shifting. This is one of the core concepts of the Hyperglide
system, and why everyone else has copied them.
Therefore, each cassette has a letter combination that is marked on each cog of that set. That designates
the cogs that are designed to work as a Hyperglide set.
If one swaps cogs and/or changes the stock Hyperglide configurations, the new cogs probably won't have their
windows in the optimal Hyperglide configuration. Therefore, one gets slower shifting, as the cassette may
have to make a 1/2 or almost full rotation before the chain will move to the next cog.
Our custom cassettes are built from stock Hyperglide cassettes, with only the end cogs changed.
This limits the slow-shifting problems.