Chain Guide, ala PVD
From Pvdwiki
By running a single front ring on my six speed MTB, I have to have a way of keeping the chain on the ring. Without a guide, the chain will fall off several times a ride.
Since I ride trails, I wanted a nice solid chain guide that didn't mount in a heavy way to a bash guard. Chainrings are the only bash guard a singletrack rider needs.
The Truvative Boxguide box is available as a spare part for about $20.
The parts included in the spares.
I machined a custom bracket to mount the box to my frame from the seat tube.
It's a super solid set-up.
139 grams. Not the lightest, but tougher than anything you can find.
Pretty slick!