The Enve SES Aero Carbon Road 31.8mm Stem is designed to make you faster through aero shaping and optimisation of bike position to give a speed boost up to 30W. This stem has been designed for road racers, triathletes, and performance-focused riders looking to improve overall aerodynamics while maintaining the stiffness, comfort and class-leading ride feel needed for prolonged day-in, day-out speed. Developing this stem involved input from Team Dimension Data, ENVE's ultra-adjustable design uses two steerer clamp shims to tune the bar height by switching the angle between -7 and -17° with a fixed length or to tune the length by +/-2.5mm with a fixed -12.5° angle. This enables fine-tuning of your bike fit, allowing you to comfortably adopt a more aerodynamic position while also reducing the need for headset spacers to create cleaner airflow. The Enve SES Aero Carbon Road 31.8mm Stem features an aerodynamic shape, low-profile clamp and the option to set it flat for minimal frontal area. Meanwhile, the regular 31.8mm clamp means it's compatible with virtually every handlebar on the market. The aerodynamic design of the stem's shape was carried out in CFD (computational fluid dynamics) software by Smart Aero Technology and then honed at the Mercedes-AMG Petronas F1 wind tunnel. The testing results revealed a valuable 0.6W average gains across a full sweep of wind angles at 40kph compared to the ENVE Road Stem. Adding the stem to its natural partner, the ENVE SES Aero Road Handlebar, saves another 5W. As riders make up 80 to 90% of total drag, the biggest savings come back to the fit. With rider positions optimised using the shims commonly seeing gains of 15-30W. To avoid ruining the aerodynamic profile through bike computer positioning, ENVE has created a Garmin/Wahoo mount specific to this stem (sold separately).The stem is beautifully constructed in uni-directional carbon fibre, giving incredible strength, an ultra-sleek shape, additional comfort and weight savings. The aluminium clamp gives a strong, reliable grip while the stem also comes with a matching top cap. Enve SES Aero Carbon Road 31.8mm Stem Features Uni-directional carbon construction Tested and raced by Team Dimension Data Wind-tunnel tested aerodynamic profile Length-offset shim for +/-2.5mm Angle-offset shim for -17° or -7° drop Compatible with ENVE Aero Road Stem Computer Mount PLEASE NOTE: This stem is intended for negative drop only and cannot be used flipped or reversed to create a positive rise. Enve SES Aero Carbon Road 31.8mm Stem Specifications Material: Carbon Length: 100, 110, 120, 130, 140mm (+/- 2.5mm with 12 degree shim) Weight: 170, 175, 180, 185, 190 grams Rise: -12 Degrees Fixed -17 to -7 degrees with shim Handle Bar Clamp Diameter: 31.8mm Steerer Tube Clamp Diameter: 1 1/8 (1.125) Faceplate Material: Aluminium Hardware Material: Titanium Stack Height: 42.5mm with length shim / 45.5mm with angle shim Torque Spec: Face Plate Upper Bolt 10Nm, Lower Bolt 6Nm Torque Spec: Steerer Tube 5.5NM