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With the new Propel, the world’s largest bicycle manufacturer is once again aiming for the title of best competition road bike. The fourth generation of this aero road bike continues its predecessor’s approach as a well-balanced all-round racing bike and promises improvements across the board: aerodynamics, lightweight construction, ride comfort and stiffness. Should the claimed improvements prove true, the new Propel will once again be a contender for the test crown and should hold its own against established racers such as the Specialized Tarmac, Canyon Aeroad and Scott Foil, as well as more recently developed rivals such as the Cannondale SuperSix EVO. The first in-depth test in TOUR will reveal just how much of these promises hold true. When it comes to weight, the model is already off to a good start: we weighed the top-of-the-range Advanced SL0 model, which has just arrived and features the SRAM Red AXS groupset, at a breathtaking 6.4 kilograms. At the same time as the Propel, Giant is introducing a new generation of its counterpart, the EnviLiv, under its women’s brand Liv.
Giant Propel Gen. 4: Key facts
Manufacturer's specifications
- Weight of complete bike: from 6.4 kilograms
- Frame/fork weight: from 800/360 grams
- Stack/Reach/STR: 565/392 millimetres/1.44 (size M/L)
- Max. tyre clearance: 32 millimetres
- Frame sizes: XS, S, M, M/L, L, XL
- Prices (complete bike): 4,999 to 11,999 euros
- Price (frame set): 2,699 to 3,899 euros
When the first Giant Propel was unveiled in 2013, it was still purely a sprinter’s road bike: a complex aerodynamic design with rim brakes concealed behind the steerer tube and seat stays, but rather heavy and rock-hard. Nevertheless, the fast bike enjoyed immediate success: Marcel Kittel won the first stage of the 2014 Tour de France on the first-generation model and claimed the yellow jersey, whilst John Degenkolb triumphed at Gent–Wevelgem that same year.
The second generation was fitted with disc brakes in 2018, but continued to follow the single-purpose approach geared towards flat stages. The third generation, unveiled at the 2022 Tour de France, however, demonstrated surprising versatility: Dylan Groenewegen sprinted to victory on stage three, whilst Michael Matthews won solo on the hilly 14th stage. With a weight of under seven kilograms, competitive comfort and still very good aerodynamics, the Propel transformed into an all-rounder that delivers strong performance on all types of terrain. The lightweight TCR model has thus almost completely displaced it from professional sport; for a time, the model was part of the elite circle of the best competition road bikes in our test programme.
Aerodynamics and total drag
Giant claims a reduction in total drag of more than 18 watts, which sounds like a great deal at first. However, Giant is referring to three components: linear aerodynamic drag at 40 kilometres per hour across an angle of attack ranging from minus 20 to plus 20 degrees, the rotational drag of the wheels, and the rolling resistance of the new aero tyres.
For wind tunnel testing, the company relies on tests carried out in the GST wind tunnel in Immenstaad and a test protocol similar to that used by TOUR. Unlike the pedalling leg dummy, Giant uses a full-body dummy that pedals along with the rider in its wind tunnel tests – a 3D-printed replica of former professional cyclist Grischa Niermann. With this setup, Giant promises an improvement of around twelve watts compared with its predecessor.
It is not only the new tube profiles that contribute to this leap in performance, but also the new 50-millimetre-high full-carbon wheels (Cadex Max) fitted with aero tyres featuring grooves, similar to those offered by Conti with the Aero111. The tyres alone are said to save more than five watts.
The new handlebar and stem combination is also likely to account for a significant proportion of the aerodynamic performance; not only does it have a flatter, more streamlined design, but is also two centimetres narrower for a comparable frame size, thereby reducing the width of the rider’s (or the full-body dummy’s) arms and shoulders. The D-shaped steerer tube and matching spacers conceal the brake and gear cables, whilst frame-specific bottle cages on the down tube and seat tube reduce aerodynamic drag.
Weight and stiffness
For the top-of-the-range Advanced SL model, Giant promises a frame weight of 800 grams in size M without paintwork, 45 grams less than its predecessor. The fork weighs 360 grams, unchanged from before. The complete Propel Advanced SL 0 is said to weigh a full 355 grams less than the previous version: the cockpit components account for 77 grams of the weight saving, the wheels 100 grams, and the tyres as much as 140 grams.
The stiffness of the frame set is said to have been improved, albeit only slightly. However, even the previous model proved to be more than adequate in all respects in these areas. An interesting side note: the global company follows TOUR’s procedures not only for wind tunnel measurements but also for stiffness tests. The presentation documents feature an image of a stiffness test rig that measures the entire system comprising the frame, fork and wheel, and bears a striking resemblance to TOUR’s test rig.
Comfort and ground clearance
According to the manufacturer, vertical compliance at the rear has increased by 25 per cent on the Propel Advanced SL thanks to a redesigned seat tube, new chainstays and the integrated seatpost. The adjustable Vector seatpost on the more affordable models also offers greater compliance than its predecessor. Front-end compliance is said to have been improved by around 13 per cent thanks to the new handlebar-stem assemblies. Tyre clearance has increased from 28 to a more contemporary 32 millimetres, meaning the Propel can now be set up for a more comfortable ride.
Model variants and specifications
Giant offers two grades of carbon: Advanced SL for the top-of-the-range model, and Advanced for the more affordable versions. There are no differences in the geometries; both are very sporty.
The Propel Advanced SL sits at the top of the range, featuring an integrated seat dome, an integrated carbon cockpit and the new CADEX Max 50 wheelsets with CADEX Aero tyres. The Advanced SL 0 is available either with Shimano’s top-of-the-range Dura-Ace groupset or with SRAM Red AXS (€11,999). For some reason, an Ultegra version featuring this high-quality frame is reserved exclusively for the Australian market. The frameset costs €3,899.
The Propel Advanced Pro features a slightly heavier frame, offers an adjustable aero seatpost instead of the integrated seat dome, and comes with Giant wheelsets featuring 50-millimetre-deep carbon rims. The CADEX Aero tyre is also fitted as standard on this model. The slightly more affordable model is also available with the top-of-the-range Shimano Dura-Ace groupset, offering significant savings: €7,999 is a competitive price for a bike with this specification. Variants with SRAM Force or Ultegra Di2 are also available, each priced at €6,499.
The range starts with the Propel Advanced: the Propel Advanced 0, priced at 4,799 euros, features Shimano Ultegra Di2, whilst the Propel Advanced 1, priced at 4,399 euros, comes with Shimano 105 Di2. At €2,999, the Propel Advanced 2 with Shimano’s mechanical 105 groupset is the most affordable option >> available here.
Jens Klötzer
Editor