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 (R) 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 (R); 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 (R) and having a radial extension (H) 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 (R) 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 (R) 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 (R); - 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 (R); 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 (R) and having a radial extension (H) 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 (R) 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 . <EOS>