Shifting and gear assembly for transmission

A bicycle transmission comprising:

• an input shaft;
• a first shifting and gear assembly;
• a second shifting and gear assembly,
• each of the first and second shifting and gear assemblies comprising:
• a hollow shaft parallel to the input shaft;
• a first gear rotationally mounted on the hollow shaft, the hollow shaft defining at least one first aperture in axial alignment with the first gear;
• at least one first cam follower disposed in alignment with the at least one first aperture;
• a second gear rotationally mounted on the hollow shaft, the hollow shaft defining at least one second aperture in axial alignment with the second gear;
• at least one second cam follower disposed in alignment with the at least one second aperture;
• a cam disposed in the hollow shaft, the cam having a minimum cam contact surface, the minimum cam contact surface having a width measured in a direction parallel to a central axis of the hollow shaft, a distance measured in the direction parallel to the central axis of the hollow shaft between the at least one first cam follower and the at least one second cam follower being less than or equal to 1.1 times the width of the minimum cam contact surface;
• and
• a shift actuator operatively connected to the cam, the shift actuator selectively translating the cam in the hollow shaft along the central axis of the hollow shaft,
• in response to the cam being axially aligned with the at least one first cam follower, the cam displacing the at least one first cam follower radially outward to engage the first gear to rotationally fix the first gear to the hollow shaft,
• in response to the cam being axially aligned with the at least one second cam follower, the cam displacing the at least one second cam follower radially outward to engage the second gear to rotationally fix the second gear to the hollow shaft;
• a third gear mounted to the input shaft, the third gear being rotationally fixed relative to the input shaft, the first gear of the first shifting and gear assembly engaging the third gear;
• a fourth gear mounted to the input shaft, the fourth gear being rotationally fixed relative to the input shaft, the second gear of the first shifting and gear assembly engaging the fourth gear;
• an output shaft parallel to the hollow shafts of the first and second shifting and gear assemblies, the output shaft being driven by the hollow shafts of the first and second shifting and gear assemblies;
• a fifth gear mounted to the output shaft, the fifth gear being rotationally fixed relative to the output shaft, the first gear of the second shifting and gear assembly engaging the fifth gear;
• and
• a sixth gear mounted to the output shaft, the sixth gear being rotationally fixed relative to the output shaft, the second gear of the second shifting and gear assembly engaging the sixth gear,
• the hollow shafts of the first and second shifting and gear assemblies being integrally formed as a single countershaft.