Old 03-30-20, 03:25 PM
Master Parts Rearranger
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Location: Seattle, WA
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Bikes: 1985 Trek 620 - 25.5"

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I have found there to be three basic eras of cog tooth profiles throughout much of the derailleur history, or at least from the '60s onward, each an improvement on the former style:

1) "Block tooth" - like you straight up used a ban saw to cut the cogs/teeth - no ramps or shift aid, caveman tech compared to UG and HG
2) Uniglide - Shimano, 1980's, twist tooth, no ramps/cutouts in the cogs, pleasant shifting with sturdy looking cogs that wore well
3) Hyperglide - Shimano, 1990+ (the modern era), with ramps/cutouts, with everyone following suit soon after

Campagnolo and Suntour used block tooth cogs for the longest time, well into/through the '80s. There was some very mild concession to UG-type teeth where I've seen some Suntour FWs essentially chip the outer edge of the corner of the teeth. Maybe a sliiiiight bevel to the teeth as well. So as good as Accushift/Accu**** Plus was, it wasn't as good as it could be. Using Shimano cog sets solved that problem. I also use more modern 6/7/8 speed chains on those systems, which helps. Lighter, reduced width, more shift-friendly.
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