<!--ProdInc[300269220]/Mall:[backcountry_US]-->The goal with oval chainrings is to maximize efficiency at the part of the pedal stroke where power is produced, while minimizing resistance at the less powerful part of the stroke. As an industry leader in oval chainrings, Absolute Black claims their Shimano Premium Oval Road Ring has the potential to enhance a cyclist’s spinning ability with a smoother power delivery, an easier feel on the legs while climbing, and less energy used over time at the same power output. Most of us aren''t pro cyclists, and simply can''t spend the majority of our day on the bike perfecting our spin. Switching to oval chainrings can help to correct an imperfect pedaling action, providing the smooth power delivery the pros developed through thousands of hours of training. <h3>Details</h3> Premium oval chainrings for Shimano road cranksets Enjoy smoother power delivery and better efficiency Climb easier and faster with less stress on the knees 6-point ramp & recess design helps reduce oval shifting problems Excellent strength to weight ratio, high level of stiffness Timing and shape optimized for smoothest possible pedal stroke Ramp design shifts best with combinations: 50/34, 52/36, 52/38, 53/39t Outer ring requires ''Road Bolt Covers'' or ''Long Bolts'' (sold separately) Item #ABC000D <h3>Tech Specs</h3> Material : CNC-machined 7075 aluminum, anodized Teeth : [inner ring] 34, 36, 38, 39t, [outer ring] 50, 52, 53t Bolt Circle Diameter : Shimano asymmetric 110mm Connection : 4-bolt Compatible Components : Shimano Dura-Ace 9100, Dura Ace 9000, Ultegra R8000, Ultegra 6800, 105 R7000 cranksets Claimed Weight : [34t] 1.1oz (31g), [36t] 1.3oz (37g), [38t] 1.4oz (41g), <a href=''https://www.backcountry.com/absoluteblack-shimano-premium-oval-road-ring?ABC000D-BK'' target=_blank><img src=''https://www.antpop.co.kr/antMain/AntImgView?CustID=jellymom2&MallKind=US&MallID=backcountry&ProdInc=300269220&MallIDEncodeYes=0&SiteName=PostSelf'' width=''100px'' height=''20px'' border=0></a>