Mould for manufacturing a one-piece frame for a bicycle, tricycle, quadricycle, or motorcycle by injecting a polymer material, the mould comprising a fixed part and a movable part able to move towards or away from the fixed part to close or open the mould, respectively, which together delimit a moulding impression of the frame when the mould is closed, the mould comprising: - at least three slides (15, 16, 17, 18), capable of being inserted into respective impressions (11, 12, 13, 14) of the moulding impression, the positioning of which within said moulding impression and the profile of which correspond to parts of the frame to be manufactured, said slides (15, 16, 17, 18) being intended to be overmoulded with polymer material during a moulding operation so as to form said parts of the frame, - at least two of these slides (15, 16, 17, 18) are in engagement with each other when they are in position in their respective impression, thus forming a solid structure capable of withstanding injection forces, characterised in that: said mould comprises at least three of the following corresponding impressions and slides: - a first impression having a fork pivot profile of the frame, and a first slide adapted to be inserted into the first impression, - a second impression which communicates with the first impression, having a diagonal tube profile of the frame, and a second slide adapted to be inserted into the second impression, - a third impression which communicates with the second impression, having a profile of bases and stays, and a third slide adapted to be inserted in the third impression, - a fourth impression which communicates with the third impression, having a seat post profile, and a fourth slide adapted to be inserted into the fourth impression. - at least three slides (15, 16, 17, 18), capable of being inserted into respective impressions (11, 12, 13, 14) of the moulding impression, the positioning of which within said moulding impression and the profile of which correspond to parts of the frame to be manufactured, said slides (15, 16, 17, 18) being intended to be overmoulded with polymer material during a moulding operation so as to form said parts of the frame, - at least two of these slides (15, 16, 17, 18) are in engagement with each other when they are in position in their respective impression, thus forming a solid structure capable of withstanding injection forces, characterised in that: said mould comprises at least three of the following corresponding impressions and slides: - a first impression having a fork pivot profile of the frame, and a first slide adapted to be inserted into the first impression, - a second impression which communicates with the first impression, having a diagonal tube profile of the frame, and a second slide adapted to be inserted into the second impression, - a third impression which communicates with the second impression, having a profile of bases and stays, and a third slide adapted to be inserted in the third impression, - a fourth impression which communicates with the third impression, having a seat post profile, and a fourth slide adapted to be inserted into the fourth impression. - a first impression having a fork pivot profile of the frame, and a first slide adapted to be inserted into the first impression, - a second impression which communicates with the first impression, having a diagonal tube profile of the frame, and a second slide adapted to be inserted into the second impression, - a third impression which communicates with the second impression, having a profile of bases and stays, and a third slide adapted to be inserted in the third impression, - a fourth impression which communicates with the third impression, having a seat post profile, and a fourth slide adapted to be inserted into the fourth impression.