How do you measure a bicycle chain?

If you cannot measure an old chain to determine what length a new chain should be, focus on the largest size sprockets of your bike and work from there. Visiting a bicycle care website, such as Bicycling.com, is a good place to view how-to videos about chain sizing.

Begin by removing the old bicycle chain. Shift the front derailleur to the largest chain ring and position the back derailleur over the smallest cog. Thread the new chain through the front derailleur. Next, wrap the remaining chain around the largest back cog and the largest front chain ring. Next, pull the chain tight and make note of where the chain should join. From the closest rivet, count another inch and cut the chain. Remove the chain from the bicycle, thread it through the front and rear derailleurs and join the ends.