Absolute Black's aftermarket Shimano Premium Round Road Ring puts a big emphasis on stiffness, resisting flex with its high strength-to-weight ratio and thicker 5mm construction. These stout aluminum chainrings feature a one of a kind look, and use Absolute Black's proven ramp and recess design for smooth and responsive shifting. They're sold separately as inner and outer chainrings, and are compatible with any Shimano 4-bolt crankset. If you're only getting an inner chainring, you can use your original bolts. If you're using the outer chainring, you'll want to purchase Absolute Black Bolt Covers or Long Bolts.