If so, why?
I didn't notice how clean these "broken" teeth are, or that the design appears to be symmetrical (also for the extra pointy teeth, second photo), until I'd fully swapped it for a new one 🥸 Yes, I know, I should pay more attention to details …
If there's a convincing reason to put it back, I'll do so.
by Inu-shonen
6 Comments
The shorter teeth are designed to allow the chain to move more easily from one chainring to another when you change gear. They’re not broken.
If it looks like that on exact opposite sides, or some other clear pattern, it’s intentional.
I’ve also learned something from this. You aren’t alone, OP (there’s at least two of us!)
It’s one of the most popular questions on this sub.
Also popular: “Can I keep riding this?” posts on either end of the spectrum. People with cracks in their frames or rims on the one extreme and then on the other extreme you have people with a tiny bit of dry rot or a 1mm cut in their tyres or a bit of surface rust who think they have to replace their whole bike.
Those are part of a design Shimano started using around roughly the late 80s. It’s designed so that the chain will shift when the crankarms are in a position in your pedal stroke that’s producing minimum power so it can shift smoother with less load. It’s related to the idea behind the shift ramps and cutdown teeth on Hyperglide cassettes. That tab on the inside of the ring goes behind the crankarm when it’s mounted.
I think you broke it on the curb.