Bionicon C.Guide V.02 Chain Guide
"The C.Guide V.02 is a great example of simple, elegant design. It's so simple and obvious you can't help but wonder why no one ever thought of it before. Actually, I've been told there was a similar chain guide in the 90s but it was a hook instead of a tubular design like the C.Guide and big hits could still knock the chain loose." - MTBR.com
A simple little gizmo that keeps the chain on. I have it on a few bikes, and never a failure. I question the price for such a little thing of metal and plastic, but the only device like it.
Put one of these on my 2x9, AM rig and love it so much I ordered another for my 1x9 rigid 29er. I haven't dropped a chain once since using these. I also notice no drag or noise from these. Removed the one from my full suspension bike for a ride and thought I'd broken something when I heard how noisy it was when riding rough rocky trails. It won't be coming off again. You should go to Bionicon's website and watch the video where they compare this thing to a clutch style derailleur before dumping a bunch of unnecessary cash. This blows those away for a fraction of the price.
I bought one of these C Guides for my 2x9 to stop chain rattling and because the chain fell off all the time. It is stupid easy to install compared to other chainguides, cheaper than most, and you don'y have to have ISCG tabs or anything. Only bad thing is, I don't run it on my bike anymore. I got busted about the 4th time I rode with it installed. I put stronger zip ties on and bent it back to the proper width, and it got busted again soon thereafter. I'm going to try something along the lines of a Blackspire Stinger next.
great little guy that does the job well. i ride rough all mountain and dh runs weekly and i have not had a chain drop in months now. i forgot what a pain it was to get them! a lil pricey but otherwise a great buy.
I was a little hesitant about how well this little chainguide would work, as I am definitely on the more agressive side of things when it comes to all mountain riding. So far after a couple weeks of heavy use on really rough trails, not had a single dropped chain. Something that would happen often on my Rocky Mountain Slayer70 when the trails got rough. It's even held up great when hitting larger jumps and drops at the bike park, so no complaints from me. Just be sure you add a couple links to your chain when you install the Bionicon, otherwise your shifting may suffer. Only slight downside in my opinion is the allen screw that holds the two halves of the guide together is kind of small. Even the manufacturer recommends putting tape or something over it to keep it in place. Surely there's a sturdier option? Regardless, does what it's supposed to quite well, even on rougher trails and larger stunts.
got one on a recommendation from a framebuilder, and it is awesome. much quieter and ever worked with the triple i was initially using.