Chain Tension 101

Q: Why do bicycle chains tend to come off?

Eli: Great question! Chains often come off because the tension between the axle and the crank arm is either to tight or to loose.

Q: Well how do you know that? 

Eli: Here you can clearly see that chain is loose. Therefore, the tension between the crank arm and the axle were either to tight or too loose, which caused the chain to fall off.

Q: So, what tools do I use?  

Eli: You wanna use two ratchets, and two sockets (size varies between nuts). 

Q: So, how do you put the tools on? 

Eli: You take each ratchet and socket and apply it to the rear of the bike on each side.

Q: How do you make the chain at the right tension?  

Eli: First, align the tire straight. You know that space between the tire and the frame, stick a tube in it to stretch out the chain. As your doing this, have someone turn the tools and this will tighten the chain. 

Q: Will the chain now be in the correct position after tightening it? 

Eli: Yes, because as you can see the slackness of the chain allows you to tighten the chain to your liking.