2018 will go down as the year that Giant dropped their atomic bomb into the aero road bike market: the Giant Propel Disc. Not only does the new design incorporate impressive aerodynamic technology from former F1 experts such as Xavier Gergaud, Giant have made a clear statement by only offering the bike with disc brakes. There isn’t much to be said about what the bike is designed for as this is plainly obvious: unadulterated speed. Whether soloing off the front of the peloton or sprinting to victory, the Giant Propel is designed to be the most efficient it can possibly be in generating speed with total disregard for all other factors. This uncompromising design may not have the vertical compliance (insert comfort) some riders want but at the end of the day no one ever claimed rocket ships were comfortable.
The engineers at Giant have gone above and beyond with the design of the all new Giant Propel. Taking wind-tunnel testing to new levels, Giant created a riding mannequin that pedalled on a bike with the wheels moving while the floor of the tunnel could be rotated by up to 30 degrees. This approach left no stone unturned in terms of aerodynamic data, which Giant has used very effectively. For example, Giant found that the disc rotors effect on the overall dynamics was negligible, especially after incorporating an asymmetrical fork design that shielded the front brake calliper. So yes, Giant did some wind tunnel testing, just like everyone one else. The difference is that they took it to the absolute extreme to gather the most realistic data possible to create a superbly aerodynamic bike.
Working in tandem with the aero profile is the stiffness to weight ratio. This is an area where Giant are claiming the top spot against all other competitors on the market. Measuring stiffness can be somewhat subjective. There are many test protocol factors that need to be considered but, for what it’s worth, Giant claim to have tested all the market leading frames with the Propel coming out as number one. The second part of this equation is, of course, weight. The Propel SL Disc frameset tips the scales at just 982 grams making it second only to Canyon’s Aero CF SLX. Without getting too bogged down in the numbers, we can say confidently that the Giant Propel Disc is light and pretty darn stiff.
The Giant Propel Disc comes in two main frame choices. The Advanced SL, which uses Giant's most advanced carbon fibre material incorporating an integrated seat mast, and the Advanced frame, which utilises Giant's advanced-grade carbon material and aero carbon seat post. The Advanced SL models are both electronic with a choice of Ultegra or Dura Ace depending on your budget. For those looking to get the technology on a more modest budget, you have a choice between the Propel Advanced Disc that comes with a mechanical Shimano Ultegra group and the Advanced Pro that is decked out with electronic Ultegra DI2.
Drive trainDura Ace Di2
Gear ratiosSemi Compact
Frame buildCarbon Pro