StuRat wrote: ↑
Nov 08 2018 7:28pm
DNP is a freewheel manufacturer (no idea what it stands for) and the only freewheel available with an 13 tooth cog.
11 tooth cog, you mean. There are others, like IRD, that have 13t small sprockets. Shimano used to make 11-34 and 11-28 7-speed freewheels, but it's been only 14-34 and 14-28 from them for many years now.
Freehub is the modern equivalent of the old freewheel.
Instead of threading onto your hub they have locating splines. It's actually a shimano product, but an industry standard.
So threaded freewheels were up until about 2000. Splined freehubs since about 2000.
The first common cassette hub was Maillard Helicomatic in the 1970s, but it wasn't exactly a freehub. The ratchet was in the cassette, but it attached to the hub with splines and a lockring much like we're used to.
Shimano type cassettes came to market in the second half of the 1980s. They've been predominant since the mid-1990s. But threaded freewheels haven't gone away. They are cheaper than cassette systems, and they work with things like trike axles, jackshafts, and hub motors that don't accept cassette gearing. So they're standard issue on department store bikes, entry level legitimate bikes, and specialty cycles.
Among cassettes, the Shimano spline pattern is most common, but there's also the concurrent and incompatible Campagnolo pattern, plus weird new freehubs designed for 10 and 11 speed MTBs with 10-50 cassettes and the like.