- A crankset (1; 100) with extensible cranks, comprising: - a bearing configured to form part of a bicycle frame; - a bottom bracket shell arranged in the bearing and in which a bottom bracket axle is mounted such that the two ends (4a, 4b) of the bottom bracket axle come out of the two openings of the bearing respectively; - an inner tube arranged inside the bearing, the bottom bracket shell passing through the inner tube; - a first circular eccentric rotatably mounted on a first of the two ends of the bottom bracket axle and fixedly connected to a first of the two ends of the inner tube; - a second circular eccentric rotatably mounted on the second of the two ends of the bottom bracket axle and fixedly connected to the second of the two ends of the inner tube, the first and second eccentrics (7, 9) having the same rotation axis that is offset from the bottom bracket axle by a predefined distance; - a first crank assembly comprising a first ring rotatably mounted about the first eccentric and a first crank arm radially extending from the first ring, wherein bearings are disposed between the first eccentric and the first ring, the first crank assembly further comprising a first crank housing fixedly connected to the first end of the bottom bracket axle and housing the first eccentric, the first ring and the first crank arm, the first crank housing comprising a first hollow arm in which the first crank arm is slidably inserted and comes out therefrom; - a second crank assembly comprising a second ring rotatably mounted about the second eccentric and a second crank arm radially extending from the second ring, wherein bearings are disposed between the second eccentric and the second ring, the first and second crank arms (14, 25) extending in the same direction in opposite senses, the second crank assembly further comprising a second crank housing fixedly connected to the second end of the bottom bracket axle and housing the second eccentric, the second ring and the second crank arm, the second crank housing comprising a second hollow arm in which the second crank arm is slidably inserted and comes out therefrom; and characterized in that it comprises: - a system for adjusting the angular offset of the first and second eccentrics (7, 9) about the bottom bracket axle, configured to adjust, by rotating the inner tube inside the bearing, the angular position of the first and second eccentrics (7, 9) about the bottom bracket axle at which the first and second crank arms (14, 25) have maximum extension relative to the first and second hollow arms (20, 28) respectively. - a bearing configured to form part of a bicycle frame; - a bottom bracket shell arranged in the bearing and in which a bottom bracket axle is mounted such that the two ends (4a, 4b) of the bottom bracket axle come out of the two openings of the bearing respectively; - an inner tube arranged inside the bearing, the bottom bracket shell passing through the inner tube; - a first circular eccentric rotatably mounted on a first of the two ends of the bottom bracket axle and fixedly connected to a first of the two ends of the inner tube; - a second circular eccentric rotatably mounted on the second of the two ends of the bottom bracket axle and fixedly connected to the second of the two ends of the inner tube, the first and second eccentrics (7, 9) having the same rotation axis that is offset from the bottom bracket axle by a predefined distance; - a first crank assembly comprising a first ring rotatably mounted about the first eccentric and a first crank arm radially extending from the first ring, wherein bearings are disposed between the first eccentric and the first ring, the first crank assembly further comprising a first crank housing fixedly connected to the first end of the bottom bracket axle and housing the first eccentric, the first ring and the first crank arm, the first crank housing comprising a first hollow arm in which the first crank arm is slidably inserted and comes out therefrom; - a second crank assembly comprising a second ring rotatably mounted about the second eccentric and a second crank arm radially extending from the second ring, wherein bearings are disposed between the second eccentric and the second ring, the first and second crank arms (14, 25) extending in the same direction in opposite senses, the second crank assembly further comprising a second crank housing fixedly connected to the second end of the bottom bracket axle and housing the second eccentric, the second ring and the second crank arm, the second crank housing comprising a second hollow arm in which the second crank arm is slidably inserted and comes out therefrom; and - a system for adjusting the angular offset of the first and second eccentrics (7, 9) about the bottom bracket axle, configured to adjust, by rotating the inner tube inside the bearing, the angular position of the first and second eccentrics (7, 9) about the bottom bracket axle at which the first and second crank arms (14, 25) have maximum extension relative to the first and second hollow arms (20, 28) respectively.