I did a derailleur adjustment on a customer's cyclocross bike.
There's something a bit unusual about it though—
It's got an MTB crankset with 42-29T chainrings mounted on it.
There are two bands on the seat tube, but
that doesn't mean there are two front derailleurs.
↑This is a homemade chain drop prevention guard.
The lightening cutouts that look like the yokai Okarina from Gegege no Kitaro—that's just my personal taste.
The spots dirty from contact with the chain are where the guard is doing its job,
（The chain doesn't actually contact the guard even in inner × low gear.
So the guard makes contact with the chain only when it's thrashing during shifting）
With this crankset, I figured out that chain drop can happen in the area behind the seat tube,
so I made this guard to cover the spots that a standard chain guard doesn't protect.
It's over two years old now, but it's still doing its job.
There's something a bit unusual about it though—
It's got an MTB crankset with 42-29T chainrings mounted on it.
There are two bands on the seat tube, but
that doesn't mean there are two front derailleurs.
↑This is a homemade chain drop prevention guard.
The lightening cutouts that look like the yokai Okarina from Gegege no Kitaro—that's just my personal taste.
The spots dirty from contact with the chain are where the guard is doing its job,
（The chain doesn't actually contact the guard even in inner × low gear.
So the guard makes contact with the chain only when it's thrashing during shifting）
With this crankset, I figured out that chain drop can happen in the area behind the seat tube,
so I made this guard to cover the spots that a standard chain guard doesn't protect.
It's over two years old now, but it's still doing its job.