The drive sprocket is also called the roller sprocket.
[1] The main dimensions and basic parameters are commonly used with chains P=12.7 15.875 19.05 25.4
dr=7.92 10.16 11.91 15.88
Number of sprocket teeth Z Pitch P Roller outer diameter dr Row pitch pt Index circle diameter d, d=p/sin180°/z
Addendum diameter da, da=d+1.25p－dr or da=p(0.54+cot180°/z)
Root circle diameter df, df=d－dr