After giving the world a heads-up at the recent Tour de France, Giant today announced the launch of its new Propel aero road bike. Giant claims that the top-of-the-line Propel Advanced SL 0 will weigh in exactly at the UCI-approved 6.8 kg limit. The new Propel's tube profile is shallower than its predecessor, a clear indication of Giant's choice to make it an all-rounder rather than a bike for flat days.

But it's not all about weight savings. Giant claims all-around improvements, including a 6.21-watt aerodynamic performance increase, 9.2% overall stiffness increase, and a whopping 85% compliance improvement with the new integrated seatpost design. Giant also says that the cockpit has been redesigned to allow for faster and easier adjustments and work.

Of course, this is not the first public showing of the new Propel. We have already peeked at it several times. The first time we saw it was in a (probably intentional) leak on Tony Martin's Instagram. The thinner tube profile in that photo confused us a bit, but it was a clue that Giant was taking the previously all-aero Propel in a new direction. We were then able to get our hands on the actual bike at Team BikeExchange's hotel before the Grande Pearl in Denmark. We were not allowed to weigh them, but we were allowed to hold them in our hands. There we also discovered a new way of integrating the aero bottle cage with the cockpit.

Fortunately for our fragile egos, today's official announcement confirms much of what we could already have guessed.

A recurring theme in Giant's marketing is the discussion of efficiency, which, at least in this context, is based on the ratio of stiffness to weight. To increase efficiency, Giant either reduced weight or increased stiffness. Giant did both.

Unlike the approach taken when launching the TCR in 2020, the Propel's weight reduction was done with a sum of all parts approach, resulting in a total weight reduction of 225 grams. The frame was a clear area of focus, as evidenced by the use of shallower tubes, resulting in a loss of 137 grams in the frame alone, down from 982 grams to 845 grams. A further 18g was lost in the fork, 17g in the derailleur hanger, and 66g with the introduction of the new integrated seatpost, with the difference being made up by small savings in headset spacers and other components. In addition, the new Giant Contact SLR aero bars and stem save 102.5g.

Balanced with these weight savings, Giant claims a 9.2% increase in stiffness. Torsional stiffness was increased by 9.9% and pedaling stiffness by 7.5%. Most of these stiffness gains are due to head tube and downtube changes, Giant's "super-sized" Powercore bottom bracket and asymmetrical chainstays.

Combined with the weight savings and stiffness gains, Giant believes the new Propel has a 26.4% higher frameset efficiency than its predecessors. It should be noted that this does not equate to a 25% reduction in watts required to maintain a constant speed.

It is well known that a stiffer frame is less comfortable to ride, but to offset this, Giant focused on improving the smoothness of the rear. The result was a narrower seat tube, chainstays, and seatstays, as well as the introduction of an all-new ISP (integrated seatpost). In addition, to further smooth out uneven road surfaces, the Propel can now be equipped with tires up to 30 mm wide.

Despite weighing 6.8 kg, the top-of-the-line Propel was designed for aerodynamics, which Giant designed using CFD (computational fluid dynamics) and refined in the wind tunnel.

The resulting frame shape is described by Giant as a truncated elliptical airfoil, found in the down tube, seat tube, and seat stays. Also new are the aerodynamically integrated bottle cages, individually designed to allow air to flow smoothly from the down tube to the bottle and from the bottle to the seat tube.

These improvements, plus the introduction of a new cockpit and the recently introduced Cadex 50 wheels, mean that the new Propel requires 6.21 fewer watts to maintain 40 km/h when tested with the cage and bottle installed than the previous model.

When buying a road bike, not everyone focuses on the top-of-the-line Advanced SL, so it is important to note which of Giant's technologies permeate the lower models.

The second-largest model, the Propel Advanced Pro, boasts the same truncated elliptical frame shape and aero bottle cage as the Advanced SL, as well as being lighter and stiffer than the previous model.

But of course a second carbon fiber layup on the second frame increases the weight, although Giant has not revealed the exact weight; the ISP has been eliminated and a standard seatpost has been adopted instead.

The 50mm-deep carbon fiber Aero wheels are tubeless compatible and are set up as such at the factory, but they are not the ultra-light Cadex wheels. Instead, the Advanced Pro is fitted with Giant's own brand wheels. Up front, the same Overdrive Aero cockpit will be integrated, but the handlebars and stem will be Contact SL Aero instead of the Contact SLR Aero mentioned above.

Meanwhile, the third grade Propel Advanced model also features the same Overdrive Aero cockpit and Contact SL Aero components. Carbon fiber wheels are forsaken in favor of entry-level alloy wheels, which are tubeless-ready and set up as such at the factory.

As expected, the Advanced has dropped the carbon fiber level even further, but carries over the Vector seatpost from the Advanced Pro.

All Propel models are scheduled for release in November 2022. Currently, only three models available in Australia have confirmed prices: the Advanced SL 0 for A$13999, the Advanced Pro with Force eTap AXS for A$8499, and the Advanced Pro with Ultegra Di2 for A$7799. A$7799 for the Advanced Pro with Ultegra Di2.