Here's a neat product that can save you big headaches on the bike.  The Third Eye Chain Watcher clamps around your seat tube and is positioned next to the inner chain ring so that the chain can not slip off due to poor dérailleur adjustment or rider error.  When the chain drops off the inside chain ring, it is typically due to poor adjustment of the front dérailleur.  However, even on a properly adjusted bike, the chain can come off when shifting under pressure from the big ring to the small ring up front while on a large cog in the rear (cross chain shifting).  In both instances, the Chain Watcher can save the day.  Even many professional cycling teams use these devices - a little chain drop insurance is good for riders at every level.

Installation of the Chain Watcher is very simple.  All of the instructions are visible in the image on the right and it took me less than three minutes to install my first Chain Watcher recently.  The Third Eye Chain Watcher isn't the only product of its kind on the market, but its design allows it to fit different seat tube diameters whereas others must be purchased in a particular size.  That may be a bigger deal for me as I ride, review and support many different bikes but it also makes the product easier to purchase.   The package states that the Chain Watcher fits "all" seat tubes.  Given the exotic shaping of some carbon bikes these days, that is obviously not the case, but it will fit virtually all traditionally tubed bikes.

The Chain Watcher adds a negligible amount of weight, is inexpensive and offers the user piece of mind.  I'm not sure there's a downside.

Mark