Essential length of roller chain
Working with the center distance amongst the sprocket shafts and also the number of teeth of both sprockets, the chain length (pitch number) may be obtained through the following formula:
Lp＝（N1 ＋ N2）/2＋ 2Cp＋｛（ N2－N1 ）／2π｝2
Lp : Overall length of chain (Pitch number)
N1 : Quantity of teeth of compact sprocket
N2 : Amount of teeth of big sprocket
Cp: Center distance between two sprocket shafts (Chain pitch)
The Lp (pitch number) obtained through the above formula hardly becomes an integer, and normally contains a decimal fraction. Round up the decimal to an integer. Use an offset link if the quantity is odd, but select an even number as much as achievable.
When Lp is determined, re-calculate the center distance between the driving shaft and driven shaft as described during the following paragraph. Should the sprocket center distance can not be altered, tighten the chain employing an idler or chain tightener .
Center distance concerning driving and driven shafts
Certainly, the center distance involving the 
driving and driven shafts has to be additional than the sum in the radius of both sprockets, but in general, a proper sprocket center distance is deemed to become thirty to 50 occasions the chain pitch. Even so, if your load is pulsating, twenty instances or less is correct. The take-up angle amongst the smaller sprocket as well as chain should be 120°or extra. In case the roller chain length Lp is provided, the center distance among the sprockets might be obtained through the following formula:
Cp＝１/4Lp－(N1＋N2)/2+√(Lp－(N1＋N2)/2)^2－2/π2（N2－N1）^2
Cp : Sprocket center distance (pitch variety)
Lp : All round length of chain (pitch quantity)
N1 : Quantity of teeth of tiny sprocket
N2 : Quantity of teeth of big sprocket