Bicycle with rear suspension and relative system of transmissions

A bicycle comprising:

• a frame;
• a rear wheel;
• a suspension system that allows a predetermined relative displacement between the rear wheel and the frame;
• and
• a drivetrain system for transmitting motion from a crankset to the rear wheel, wherein the drivetrain system comprises a crankset fixed to the frame, a hub and pinion assembly fixed to the rear wheel that is rotatable about a common pivot axis thereof, and a drive chain that connects the crankshaft and hub and pinion assembly directly to each other;
• wherein the crankset and the hub and pinion assembly are subjected to reciprocal displacement by the action of the suspension system;
• wherein at least one among the crankset and the hub and pinion assembly comprises a free stroke device placed to allow both a forward and backward free angular stroke of the chain with respect to respective pivot axes of the crankset and/or of the hub and pinion assembly;
• wherein the angular stroke is limited by a predetermined angle of entity related to the relative movement between wheel and frame;
• wherein the forward stroke is one that occurs both in the passage from an extended position to a compressed position of the suspension, and at the start of the pedaling in extended position of the suspension, the free stroke device comprises a first damper that acts for the entire forward angular stroke, opposing the forward angular stroke, and the free stroke device comprises an additional damper that acts only in a final stretch of the forward angular stroke, opposing final stretch of the forward angular stroke.