AbsoluteBlack Teases 40-Tooth Cassette Cog
The OneUp 42t cog got quite a bit of attention, and seems to be working out pretty well for Zach after a few tweaks to the rear derailleur. But, AbsoluteBlack founder Marcin thinks he’s got a better solution.
In development for a couple months now, his 40-tooth cog works the same way as OneUp’s: You remove one of the middle cogs to make room for a larger one at the top. The most superficial difference is that it uses two less teeth, which he says eliminates the need to tweak the B-tension screw. In theory, this means the expanded gear range comes with no major adjustments outside of the cassette.
There’s more to it than that…
The tooth profiles are heavily shaped to make shifting crisp and fast. Sets of four up- and six down-shift teeth run around the cog, alternating to provide large swaths of shifting sections that should grab or release the chain on demand.
Marcin says there are two other features that set his design apart. First, it’s about 7g heavier (~77g target weight), but those extra grams are used to make the splines very stiff, which should mean solid shifting and driving. Second, the splines that contact the freehub body maximize the surface contact area, which should reduce the chance of the cog digging into the freehub body, particularly alloy ones. OneUp’s also address this by using wide splines, the main difference here is the height of the holes is lower, so the cog is resting on the top of the freehub’s grooves, too. Time will tell if that makes an appreciable difference – we’re hoping to have one in for testing soon.
He’s shooting for an end of January release. Pricing TBD.