R1 = D/d = Sprocket Ratio
R2 = D/l = Drive Aspect Ratio
R3 = c/d = Constant Ratio
R1 must be less than 4
R2 should be less than or equal to 0.5
R3 should be less than or equal to 0.85
Standard SI not applicable.
Use SI-SG1 or SI-SG2
"The Snapidle chain tensioner is easier to install and maintain than the adjustable sprocket tensioner. The Snapidle is generally made out of UHMW-PE and stainless steel hardware with the strap having the option of being stainless steel. It is self-adjusting because of its unique design that allows it to slide up and down the drive chain wherever there is slack. Its reliability and lack of needed maintenance make it the tensioner of choice." -Allied-Locke Industries