Bicycle sprocket, comprising a plurality of teeth arranged one after the other along a circumferential direction and a plurality of spaces each of which being arranged between two of said teeth, wherein said plurality of teeth includes: - at least one first gearshifting tooth; - at least one second tooth arranged immediately downstream of said at least one first gearshifting tooth with reference to a rotation direction of the sprocket during pedaling; and wherein said plurality of spaces includes: - at least one first space defined between said at least one first gearshifting tooth and said at least one second tooth and having a predetermined circumferential extension; - at least one second space arranged downstream of said at least one second tooth with reference to said rotation direction; wherein said at least one second space has a circumferential extension greater than that of said at least one first space; wherein the sprocket comprises at least one spur arranged downstream of said at least one second tooth with reference to said rotation direction and having a radial extension substantially equal to that of said at least one first gearshifting tooth, wherein said at least one spur is a radial protrusion which is formed on the sprocket and which is never engaged by the chain during pedaling; wherein said at least one second space is defined between said at least one spur and a respective third tooth arranged downstream of said at least one spur with reference to said rotation direction and a further space is provided between said at least one spur and said least one second tooth; characterised in that the further space has a circumferential extension greater than that of said at least one first space. - at least one first gearshifting tooth; - at least one second tooth arranged immediately downstream of said at least one first gearshifting tooth with reference to a rotation direction of the sprocket during pedaling; and wherein said plurality of spaces includes: - at least one first space defined between said at least one first gearshifting tooth and said at least one second tooth and having a predetermined circumferential extension; - at least one second space arranged downstream of said at least one second tooth with reference to said rotation direction; - at least one first space defined between said at least one first gearshifting tooth and said at least one second tooth and having a predetermined circumferential extension; - at least one second space arranged downstream of said at least one second tooth with reference to said rotation direction; wherein said at least one second space has a circumferential extension greater than that of said at least one first space; wherein the sprocket comprises at least one spur arranged downstream of said at least one second tooth with reference to said rotation direction and having a radial extension substantially equal to that of said at least one first gearshifting tooth, wherein said at least one spur is a radial protrusion which is formed on the sprocket and which is never engaged by the chain during pedaling; wherein said at least one second space is defined between said at least one spur and a respective third tooth arranged downstream of said at least one spur with reference to said rotation direction and a further space is provided between said at least one spur and said least one second tooth; characterised in that the further space has a circumferential extension greater than that of said at least one first space.