Our Premium Shimano 110/5 (bolt pattern) oval chainrings are designed for pre 2014 cranks like Shimano Dura-Ace FC7900, Ultegra FC6750, Shimano 105 -5750 and many more with 5 bolt fitting. These are finest shift-able oval chainrings on the market. Both, inner and outer oval chainrings are optimized with smooth shifting in mind. This is why the back of the Absolute Black Oval road chainring does not feature cutouts, like other oval products on the market. Instead, we design smooth angled surfaces, to help chain to slide quickly and precisely between chainrings. Absolute Black outer oval chainrings have 6 up-shifting ramps, for easy and quick gear change, even under load. Each outer chainring also features 12 down-shifting points. Instead of steel shifting pins we use a CNC machined ramp and recess solution. Special raised ramps work in conjunction with the tooth recesses to stabilize the chain when shifting. Our oval chainrings DO NOT require any modification to the (standard) front d?railleur in order to work properly.Size (Weight):34T (30g)36T (36g)38T (41g)50T (122g)52T (135g)Compatibility: Shimano Dura-Ace 7900,7950, Ultegra 6750, 6700, Shimano 105- 5700, Tiagra 4650, FSA, Rotor 3D & 3D+, S-works and many more older cranks. Also fits Sram Force and Red but NOT compatible with Sram cranks that have 1 hidden chainring bolt (Force22, Red22). Compatible with Di2Bolts: For Outer chainring please order Long bolts. Changing Inner chainring to oval only? Simply use original boltsMaterial: CNC machined 7075 Txxx Aluminum. Long-lasting constructionMounting: 110 BCD x 5Ovality: Optimized to each size separately. 34T- 6.5% ; 36T- 11.4%, 38T- 11.4%, 50/52 - 10.3% ; Timing of 108 -109.5° after TDC (top dead center) - Ideal for road climbing. Patent PendingAdvantages of Absolute Black Road Oval chainrings:One of a kind special oval shape that helps you climb easier and faster (Patent Pending)Over 15% stiffer than Rotor Qrings due to thicker, 5mm constructionBespoke Absolute Black 6 point ramp and recess shifting design shifts better than any other brand and model of oval chainringFinest design that provides excellent strength to weight ratioYou will not feel the oval shape while pedalingYour pedaling action will feel smootherHelps reduce stress on knees and helping your legs remain fresher for longerYou will be able to maintain better cadence while climbingReduces possibility of leg crampsYou will reduce chainring/cog shifts by at least 15%IMPORTANTIf you currently use 53/39T chainrings you have 130BCD cranks (not 110bcd). In this case please look at our 130BCD chainrings as you will not be able to use anything smaller than 53/39T.