How to tell chain #

[BigThieme]

So I have a chain but how do I know the chain number

 

[itsid]

measure the roller center distance, space between the rollers and chain width (inner width)

and let us know the results

3/8" roller center distance will be a #35
1/2" a #40 or #41

'sid

 

[landuse]

You can have a look at these

The complete guide to chain and sprockets
http://chain-guide.com/applications/index.html
http://www.gizmology.net/sprockets.htm
http://jleibovitch.tripod.com/id240.htm
http://en.wikipedia.org/wiki/Roller_chain#Chain_strength

 

[Scout]

Most good chains have the size number stamped in the side plate.