BCM 600 Ate My Chainring

[swiss hat]

Hi just out of interest what chain inch do you chaps use on BCM?

A medium gear for me on BCM of 42 x 16 = ~69".

[Reg.T]

Not BCM, and not my chainring, but was just changing the chain on my fixed and discovered this:

 

Is this sort of thing common? (It's a Miche Quick Change cog)

(Coincidentally, I also lost a tooth from my mouth yesterday).

[LittleWheelsandBig]

I saw what you did there!

Yes, cogs break off teeth sometimes. They are often hardened for long life and that makes the steel more brittle. Manufacturing tolerances mean that some break and others don't.

[Ian H]

Less likely with 1/8 th chain and cogs.

[The Seldom Killer]

True, I've only knocked two teeth off 1/8 cogs. OTOH, I once saw a good gap on a roundabout, stuck a bit of power in to take advantage and a sudden chain shipping left me stranded on the island in the middle. On inspection that had less teeth left than were missing.

The remaining dimples meant I could ride up the hill back home but I didn't dare take it any further than that.