Here's a lightweight and reliable solution that keeps your chain in place: K-Edge's Cross Single Chain Catcher. Both the clamp and "foot" are made of CNC'd aluminum so you know they're light and strong. The foot keeps the chain from derailing to the inside (which can result in frame damage), and it has a tab that keeps the chain from jumping off the top of the ring. Run it with a ring guard (sold separately) in place of the big ring for light, secure set up. And, installation and positioning are easily achieved with the simple design!