1. The problem statement, all variables and given/known data A bicycle of a mass 15kg resting in a vertical position, with the front and back wheels touching the horizontal ground at points P and Q respectively, where PQ=1m. The centre of gravity of the bike is vertically above O, a point on PQ where PO=30cm. Given that the normal reactions of the ground on the front and rear where are R1 and R2, write 2 equations in R1 and R2 which satisfy the conditions of equilibrium. 3. The attempt at a solution So I know you have to use the principle of moments to give the equations. I am just unsure where the pivot is. Is it at the line of center of gravity of the bicycle?