A bicycle chainring for engagement with a drive chain provided with rollers, the chainring comprising: a plurality of teeth extending from the periphery of the chainring , the roots of the plurality of teeth being disposed adjacent to the periphery of the chainring , the plurality of teeth including a plurality of narrow teeth and a plurality of wide teeth , the narrow and wide teeth being arranged in an alternating manner, each of the teeth having a front flank and a rear flank with respect to a drive direction (DD) of the chainring , wherein the front flank and the rear flank of two adjacent teeth define an U-shaped space when seen in the axial direction of the chainring for accommodating a roller of the drive chain, wherein each tooth includes a first chamfer in the front flank and a second chamfer in the rear flank , the first chamfer starting from the top of a respective tooth , wherein both the first chamfer and the second chamfer extend on respective planes which are perpendicular to the plane of the chainring , wherein the first chamfer has a larger extension than the second chamfer , when viewed in the axial direction of the chainring , such that the U-shaped space , when viewed in the axial direction of the chainring , is steeper at the rear flank than at the front flank , characterised in that wherein the first chamfer is followed by a steep section (13"), the steep section (13") being steeper than the first chamfer when seen in the axial direction of the chainring , the steep section (13") extending up to a further section of the front flank which is responsible for the transmission of the force from the roller. a plurality of teeth extending from the periphery of the chainring , the roots of the plurality of teeth being disposed adjacent to the periphery of the chainring , the plurality of teeth including a plurality of narrow teeth and a plurality of wide teeth , the narrow and wide teeth being arranged in an alternating manner, each of the teeth having a front flank and a rear flank with respect to a drive direction (DD) of the chainring , wherein the front flank and the rear flank of two adjacent teeth define an U-shaped space when seen in the axial direction of the chainring for accommodating a roller of the drive chain, wherein each tooth includes a first chamfer in the front flank and a second chamfer in the rear flank , the first chamfer starting from the top of a respective tooth , wherein both the first chamfer and the second chamfer extend on respective planes which are perpendicular to the plane of the chainring , wherein the first chamfer has a larger extension than the second chamfer , when viewed in the axial direction of the chainring , such that the U-shaped space , when viewed in the axial direction of the chainring , is steeper at the rear flank than at the front flank , characterised in that wherein the first chamfer is followed by a steep section (13"), the steep section (13") being steeper than the first chamfer when seen in the axial direction of the chainring , the steep section (13") extending up to a further section of the front flank which is responsible for the transmission of the force from the roller. <EOS>