Rivendell OM-1 Rear Derailer

If you're a reader of the Rivendell newsletter, you definitely know what this is since it's been in the works since 2018 or so. If you're curious and don't know, read on!

When using friction shifters with standard derailers, first-timers will immediately notice that the left and right levers don't operate in the same direction. The OM-1's alternate derailer design, called variously "low-normal", "rapid-rise", or in this case "Opposite-Movement", makes it so that both levers have their neutral position in the easiest gear.

Why isn't this the default? Historically contingent reasons, like everything else in the world. It's been tried a few times but never caught on enough that the big parts makers kept with it. It sometimes takes an inordinately passionate small company like Riv to keep good ideas around. They do that a lot, it's one of the main reasons we love 'em.

If you're using indexed shifters, none of this really matters. I'm sure you could index this derailer but why would you?

Technical details, if you want 'em

• Max. cog: 36t. 
• Chain wrap: 39t. If you're maxing out the rear cog this means you can have a 14-tooth difference between your largest and smallest chainrings up front.
• Made in Taiwan by Microshift. They know derailers, and bless 'em for making this.