OkaySaw a chain keeper used in a You Tube video (Chris Horner's bike washing video) where a chain keeper is used to keep the chain taught with the rear tire removed, searched on Amazon and found this one by Pedro's. Works great, allows me to remove the rear tire, and still do chain cleaning, etc. without damaging my bike. My only peeve is that there were no instructions, not even a simple diagram, which would have been helpful for first time user. Otherwise I am happy with this simple device.Once attached to my bike, it allows the chain to no longer rub across the chain stay and acts as a rear chain 'channel' that your chain slides through and around allowing the chain to move or just be held in place . The downside is that there are just too many loose pieces that easily fall and its quite cumbersome to attach. (I'm sure its design was to accommodate almost every bike on the planet- but that is whats wrong with it) There are SEVEN parts (four of them small- including a spring that loves to fly away and the actual 'track' is two pieces that split apart- I had to use a tiny zip-tie to keep it together) that all need to be assembled and disassembled each time its attached and then again when its removed. I have yet to not have a part pop-off and fall during each process. Try removing the rear tire, wrapping a greasy/dirty chain around it and fumbling with assembling this and attaching it to your chain-stay without cursing its design- its just not possible. It does work great.... once its attached.Pedro's Chain Keeper Bicycle Chain Tool allows you to manoeuvre the chain without the bike's rear wheel on during maintenance/cleaning. I have used it to effectively hold the chain while rotating the pedals forward and wiping the chain clean. Meanwhile, the rear wheel is also much more accessible to clean and maintain. Pedro's Chain Keeper provides an effective approach to productively accomplishing maintenance. It adds convenience and simplification to the common care and upkeep duties of the cyclist. I purchased this product because I was annoyed with the unpredictable deformity of the chain whenever the rear wheel was removed. This was discouraging to my maintenance plans, and possibly even detrimental to the functionable value of the bicycle and its parts. I would recommend this chain keeping tool to others with similar circumstances because of its effectiveness with simplifying some mechanical processes. This can make some work projects more enjoyable, and in the long run, be a major contributor to adding value to the bicycle.Definitely works, just takes some time and dirty hands to learn how. The instructions just don't show enough. Each side of the device has a large or small diameter cylinder designed to fit inside the chain-stay opening where the hubs would go, so you need to figure which one works for your bike first. Then assemble the Keeper with the narrow nose pointing toward the crank and the quick-release on the inside of the chain-stay. Easiest transfer is to have the bike on a repair stand and slide the Keeper in as the wheel is dropped out.This is a handy little attachment for keeping the chain out of the way when the rear tire is off. Highly recommend if you take the rear wheel off often.Wasn't sure how helpful this little gadget would be, but after I used it for the first time when I changed a flat and subsequently cleaned and re-lubed the chain, I decided it was worth the purchase! Makes it easy to do maintenance with the back wheel off the bike. Just a bit overpriced IMO.Small. Inexpensive but really does the job. I use it on my tandem so I can make the bike fit behind my car on the rack. Have found it easy to install and remove. I had a problem when someone else installed it and the cheeks came apart, but a touch of crazy glue solved the issue. Now I keep a second with my bike tools.I can rotate the pedals to position them for best tie down on my rack and the chain just slides through the keeper. And with care I can remove and install my rear wheel and stay clean. Definitely a keeper!Igual soy un poco tonto pero no soy capaz de usarlo. Demasiado corto no llega a poder usarse el cierre rápido de manera natural en lugar de la rueda trasera. Aún sigo dándole vueltas a como se usa...