Originally Posted by
Tourist in MSN
It is clear you need a new middle chainring, very odd wear pattern of some teeth being more worn down than others....
"...In addition to the ramps and pins, modern chainrings designed for derailer use often have the teeth in the area adjacent to the ramps cut with shorter peaks than the other teeth, again to facilitate upshifts..."
https://www.sheldonbrown.com/images/ramps-pins.jpg
"...most newer rings have teeth that do not all look the same. While they are spaced at a consistent interval (to match your chain’s pitch), the heights and profiles can differ significantly. Depending on what is done to the teeth, the shaping can aid in shifting up-and-on-to the big ring, and also accurately dumping down to the small ring..."
https://www.slowtwitch.com/articles/...ks_intro_2.jpg
those rings don't look that bad, and a closer look at the cassette doesn't show that much wear either.
how 'bout just clean it all up, check the chain for wear, lube & ride.
https://cimg0.ibsrv.net/gimg/bikefor...e69aae9ac.jpeg