1. The problem statement, all variables and given/known data Power=P, rotation speed n1, rotation speed n2, chain center distance c, life = Lh All I need for this one is the formula for sprocket diameter. I have found calculators (https://www.rbracing-rsr.com/calcsprocketdiam.html) but no reference to the formula. Chain pitch and number of teeth given. Variables are say teeth=19 and pitch 15.875. Chain link pressure, I guess calculated with simple surface pressure formulae. Find resonance frequencies of transverse vibration. 2. Relevant equations From DIN 8187 tables: Width b2=13.28mm, pin diameter d2=5.08mm, bearing area A=2.02cm2, breaking load Fbmin=66700N, mass q=2.7kg 3. The attempt at a solution Surface pressure p=F/A, I however, do not know the force that the sprocket will exert on it and I guess it is not the breaking load. I'm guessing there could be radial forces on it? Or is it only a tensile stress (σ=F/A) between links? I have no clue how to approach the third one.