Shimano's Deore XT SM-CRM85 stiff and lightweight chainring delivers smooth pedalling over bumpy terrain. The SM-CRM85 chainring features Shimano Dynamic Chain Engagement+ technology, which features special gear teeth profiles that deliver exceptional chain engagement and chain retention.Special MTB gear teeth profile improves chain engagement and retentionExchangeable single/double chainringCrankset can be used as common componentDynamic Chain Engagement (DCE) is used to hold the chain and help prevent chain jump out. This is achieved by using a broader and taller tooth profile in conjunction with a special hooked leading edge and alternate profiled tooth shaping. This provides superior chain retention, lower driving sound, increased durability and drag to a minimum.