I fear my bike has a fracture in its front cog. I first noticed


Sure has. Upgrade your crankset. Stay away from Suntour stuff... they're
cheap stuff made for people who don't really ride.

At the very least, stick with Deore-level (FC-something22) cranks or higher.
They should be no more than $50-60 at your local bike shop.

Don't get anything with riveted chainrings... that's an indication of
inferior quality.

--
Phil, Squid-in-Training