Bicycle with rear suspension and related compensating device of the travel of said suspension

A bicycle comprising a frame, a rear wheel a suspension system of the rear wheel relative to the frame which allows a predetermined relative displacement therebetween, a drive system of the motion from a crankset to the rear wheel wherein the drive system comprises a crankset fixed to the frame a hub and pinion assembly fixed to the rear wheel, and a drive chain positioned to connect them directly to each other, wherein the crankset and the hub and pinion assembly are subject to reciprocal displacement by the action of the suspension system, wherein the crankset and the hub and pinion assembly each comprise at least one gear wheel engaged by said chain and a rotation shaft, wherein a compensating device is operatively interposed between the gear wheel and the shaft of at least one of said crankset and said hub and pinion assembly, the compensating device being positioned to allow an angular compensating stroke therebetween from a resting position, corresponding to no chain pull, to a compensating position, corresponding to a chain-pulling action generated by said reciprocal displacement, and vice versa, wherein said compensating stroke is limited to a predetermined angle, said compensating device comprises two main bodies which are rotatable with respect to each other and integrally to the gear wheel and to the shaft, respectively, characterised in that a blocking device of their relative motion is operatively interposed between the two main bodies, which relative motion can be selectively activated and deactivated to prevent or allow the compensating stroke.