The cockpit has been completely redesigned with an innovative new two-piece Contact SLR Aero handlebar and stem setup that makes it easier to change components and dial in a precise fit. This new OverDrive Aero system keeps the cables and hoses hidden from the wind while avoiding the complexities associated with fully integrated handlebar/stem designs that are common with many of today’s aero road bikes. The new Contact SLR Aero carbon handlebar has flattened tops for aero efficiency and hand comfort, along with a deeper drop for added control while sprinting, cornering and descending.

The guiding design principle behind the new Propel is its AeroSystem Shaping Technology. This is a process that can be viewed as a sum of all parts. It’s about analyzing every tube, junction, angle and component—both individually and, more critically, as a holistic system. The goal when creating all the different parts that make up this system is to simulate real-world riding conditions. The engineering team starts this process with airflow simulation software called computational fluid dynamics (CFD). After all the numbers are crunched, the physical forms are created. Then comes wind-tunnel testing, followed by the final step, which is to produce sample bikes and test them on the road with our pro athletes.

The new Propel Advanced SL is crafted with Giant’s most premium raw carbon fiber and cutting-edge manufacturing techniques to achieve a greater stiffness-to-weight ratio than the previous generation. For competitive racers, nothing matters more than power-to-weight, so making the new Propel both stiffer and lighter was essential. Tests show that the new frameset is not only one of the lightest in the aero road category, but it also achieves significant gains in stiffness. Lighter weight plus increased stiffness equals better efficiency on the road. When determining the precise tubing shapes and diameters, along with the layup of the Advanced SL Composite material that’s used to create the frame and fork, Giant engineers focused on two key areas of stiffness: frame stiffness, which determines the amount of overall frame and fork torsional flex under load; and pedaling stiffness, which measures the lateral flex of the bottom bracket area under load.