Tightening the Chain
 

Hi. I am looking for information about something I read about called a "chain tensioner". The chain on my 3+ year old bike is loose and keeps slipping off. Dangerous! Apparently a tool called a chain tensioner can simply fix this problem without taking the thing to a mechanic. I want to learn how to do this but a search for chain tensioners returned dozens of different looking tools, and I don't just want to buy one and hope it's the right kind. Any suggestions as to my next step?

Thanks in advance
Z

What kind of bike? A Chain tensioner is used normally on a multi-speed bike that has been converted to a single speed. If your bike is a multi speed and you have the problems you have described, you may need a new chain and freewheel or cassete (rear wheel gears) and or a chain-ring or two (front gears). This work can be done by the home mechanic. If you want to learn, check out Sheldon Brown and Park Tools.

http://www.sheldonbrown.com/
http://www.parktool.com/repair/byregion.asp