Chain Length Calculator




For our FLT/H Chain drive conversions we supply a 120 link O-Ring EK Chain.


We also have a Sprocket Diameter Calculator that determines a sprockets diameter based on the pitch of the chain and the number of teeth.

We use Sprocket Specialists for many of our sprockets and since we raced bikes at the Bol D'Or in 1977. We also use PBI for sprockets for our Harley chain drive conversions. They use 7075-T6 aircraft structural aluminum. We had Aerodynamic Plating anodize our sprockets and Jackshaft assembly pictured above.

Roller Chain Definition

Input Answer
p = Chain Pitch (inches)
n = Number of Countershaft Sprocket Teeth
N = Number of Rear Sprocket Teeth
c = Center to Center of both sprockets (inches)
Number of Links **
Chain Length (inches)
Sprocket Reduction Ratio
Chain pitch for 520, 525, and 530 chains is .625 inch_________ Chain pitch for a 630 chain is .750 inch
Chain Pitch for 420, 425, 428 is .500 inch. (Harley double row primary chain is 428)

** Note: If your result is an odd number of links add one link to get an even number