Our Winter line of Shimano 110/4 bcd oval chainrings is designed for new type of Shimano cranks like Dura-Ace 9000, Ultegra 6800, 105- 5800 and others. This is a simplified version of our Premium line. Same aluminium, teeth and shifting ramps, but less material machined out on the outer side for easy maintenance and cleaning on winter training bikes. Weight is increased on these chainrings as compared to our Premium line for that reason.Winter line chainrings are a simplified version of our state-of-the-art Premium line. They use same aluminium, teeth and shifting ramp design. However they are less machined out from the front for easy maintenance and cleaning when used on winter bikes. This chainring is designed for your winter/training bike where weight is not an issue, but easiness of cleaning is.Size (Weight):34T (40g)36T (44g)50T (156g)52T (168g)Compatibility:ÊShimano Dura-Ace 9000, Ultegra 6800, Shimano 105 5800, Tiagra 4700. Compatible with Di2 & Pioneer, SRM and other power metersMaterial: CNCÊmachined 7075 Txxx Aluminum. Long-lasting constructionMounting: 110 BCD x 4Bolts:ÊFor Outer chainring please order Long bolts. Changing Inner chainring to oval only? Simply use original bolts.Ovality: Optimized to each size separately. 34T- 6.5% ; 36T- 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 Winter 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 AbsoluteBlack 6 point ramp and recess shifting design shifts better than any other brand and model of oval chainring30% heavier than our Premium chainirngs, but very easy to clean after winter training.You 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%