Calculating Gear Size

[jamiephillips]

Does anybody know a formula for calculating gear size in inches, starting with chainring and sprocket size? Tried the search function but nothing came up.

Thanks in advance.

 

[Offtheback]

chainring x 27, divided by the sprocket. eg: 53 x27 divided by 12 =119.25 inches

 

[jamiephillips]

Thankyou Offtheback!

 

[krebs303]

Easy Gear Calculator