[PUGACHEV]

Nine speed cassettes, or rear sprockets, are quite common. With three chain rings on the front, that gives you twenty-seven speeds.

[Eric in the Ozarks]

A bike shop builder I knew made a 45 speed, based on a Schwinn Paramount way back in my teens. He added a 3 speed hub from an early 60s English bike but I suspect some of the ratios were duplicated.

[NCLaw441]

I understand that there are 27 gear combinations, but isn’t there any actual overlap in the gearing? I have an 18 speed (I think, been a while since I have ridden it) but only used maybe 6 or 8 of the gears, for the most part.