Giant has unveiled what it calls the “lightest Propel ever”, the aero road bike dropping a claimed 355g, promising an 18.4-watt aerodynamic saving at 40km/h (25mph), and gaining 2mm of tyre clearance. As some of Giant’s rivals have released increasingly radical aero bikes in recent years, why hasn’t Giant pushed the design further, and what does this mean for the future of its TCR race bike? We have all the details below, along with my first-ride impressions on the new Liv EnviLiv, the women’s-specific version of the Propel.
Now in its fourth generation, the Propel continues as Giant’s aero race platform, but for the first time it has been designed as a “total speed system” – integrating the frameset, cockpit, wheels and tyres as one cohesive unit.
As well as the top-level Giant Propel Advanced SL, the line-up includes the less expensive Giant Propel Advanced Pro and the Giant Propel Advanced. Giant uses two composite grades: Advanced SL and Advanced. The Advanced SL model features the top-tier Advanced SL composite frame and fork, the Advanced Pro pairs an Advanced composite frame with an Advanced SL fork, while the Advanced model uses the Advanced composite for both frame and fork.
Here are the headline claims – including a lot of stats – comparing the new Giant Propel Advanced SL with the previous generation:
- The complete bike is 355g lighter
- The new model improves aerodynamic drag by 18.4 watts at 40km/h (25mph)
- Stiffness-to-weight ratio increases 5.7%
- A 25% increase in seatpost vertical compliance
- Front-end compliance has increased by 12.8%
- You can run tyres up to 32mm wide
Just to be double clear, these are all claims directly from Giant, not verified by us here at road.cc.
We haven’t ridden the Giant Propel Advanced SL yet, but I’ve spent time on the women’s-specific Liv EnviLiv, which shares almost everything with the Propel – the same wheels, integrated cockpit, full-system aero design, and the same tyre clearance. Now in its fourth generation, the EnviLiv has been developed to prioritise weight reduction without compromising aerodynamics or stiffness. Read on to find out how it handled.
The bike is built around a female mannequin with slight differences in geometry, and the complete system is claimed to be 411 g lighter than the previous generation.
Improved aerodynamics… naturally
The Propel has always been the aero road bike in Giant’s range, sitting alongside the lightweight TCR, which is more about stiffness-to-weight, so it makes sense that improving aerodynamics was central to the design process.
> Best aero road bikes
As with the previous generation, the design is guided by Giant’s AeroSystem Shaping Technology. Giant has been using this AeroSystem Shaping Technology name for its approach for years. Like other brands, it starts off the design process using CFD (computational fluid dynamics) software before creating physical forms and moving on to the wind tunnel.
Most manufacturers either measure the bike in isolation or with a static mannequin on board, but Giant uses Grischa 2.0, which is a dynamic mannequin. Like Grischa, Liv uses Georgia, which was designed around Australian cyclist Georgia Baker, with the brand claiming it is the only one to design around female anatomy.
“Grischa 2.0 features a more accurate leg reproduction, especially overall leg length and thigh shaping. And the new foot form is an exact replication of the foot and shoe combination, so an actual shoe is no longer required. The head is now interchangeable and the neck angle highly adjustable, making it easier to test airflow over and through a helmet and down the back”, says Giant.
Despite the new Propel looking similar to its predecessor, Giant says that it has refined key aero zones, including the head tube, fork, down tube and seatstays. The result is a claimed 18.4 watt saving over the previous generation – equivalent to 72 seconds over 40km at 40km/h.
We need to do our usual explanation of that type of statistic here. Of course, anything moving at 40km/h will cover 40km in the same amount of time: an hour. What Giant means is that you’ll be able to achieve that speed at a slightly reduced power. If you rode at the same power, you’d cover 40km in 58:48mins.
It’s important to note that the claim relates to the bike as a whole and that the new proprietary Contact SLR Aero handlebar and stem, and the new Cadex Max 50 WheelSystem and Aero tyres are said to contribute to the reduction in drag.
“The Contact SLR Aero Integrated and Contact SL Aero Integrated handlebars are shaped with a flat back and narrow top to help slice through the wind. The bars have a new geometry with reduced width at the tops and drops to narrow the rider’s shoulder and frontal area,” says Giant.
As with the previous generation, the brake hoses and any cables are fully integrated. They run through the handlebar, exit at the centre, pass beneath the stem, and then enter the frame alongside the D-shaped steerer.
“Lightest Propel ever”
Giant says that the new Propel is the lightest yet, with the top-tier Propel Advanced SL frame said to be 45g lighter than the previous generation at 800g (863g for the Propel Advanced Pro and Propel Advanced frame), and the complete bike claiming to be 355g lighter, thanks to the new one-piece Contact SLR Aero Integrated handlebar/stem and new Cadex Max 50 WheelSystem and Aero tyres.
The new Contact SR Aero cockpit is said to reduce the overall weight by 77g, while the wheels and tyres combined shave another 140g.
In its lightest configuration, the complete bike is claimed to weigh just 6.5kg (size M) – 300g below the UCI’s 6.8kg minimum weight limit. So where does that leave Giant’s TCR all-round race bike? More on that below. As with the Propel, weight reduction was a key focus for the new EnviLiv, which Liv claims is 422 g lighter than its predecessor.
Improved stiffness
According to Giant, the aim was to at least match the stiffness of the previous generation, but the brand says it has managed to increase the stiffness, making the new Propel Advanced SL “quicker and more dynamic than ever”.
It says that its engineers have modified sections of the fork crown, head tube junction, bottom bracket and handlebar to produce most of the gains in stiffness.
The claims are a 2.4% increase in pedalling stiffness, 3.3% in frame torsional stiffness (the frame is locked at the rear dropouts with lateral force applied to the fork), and 3.4% increase in fork stiffness. Combined with a lighter frameset, that equates to a 5.7% improvement in stiffness-to-weight ratio, delivering what Giant describes as an “instantaneous reaction when you put power into the pedals”.
More compliance
Factors like compliance and control also come into play in determining the overall performance of a bike.
With this in mind, Giant says that one of the biggest advancements with the new Propel range is that there has been a greater emphasis on full-bike compliance. The seatpost, fork, cockpit, seat tube and chainstays have all been re-engineered with the aim of smoothing the ride.
The Propel Advanced SL features a Vector integrated seatpost with 25% greater compliance than the previous generation. The fork and integrated cockpit add 12.8% compliance at the front.
“Additional tyre clearance allows for high-volume tyres up to 32mm, further smoothing out the ride to help you maintain higher speeds with less fatigue,” says Giant.
Many recently launched aero road bikes can take wider tyres; the latest Cervelo S5 can handle tyres up to 34mm, for example.
Geometry: no big changes
There are no radical changes to the geometry of the 4th-generation Propel Advanced SL which, given our previous acclaim of the handling characteristics of Giant’s flagship aero bike, is no bad thing. Most of the key geometry measurements remain unchanged from the previous generation, including reach, wheelbase, chainstay length, stack, and head tube angle, with the seat tube angle increased by 0.5°.
Compared with the Propel Advanced SL (size M), the EnviLiv (size M) has a slightly shorter reach (-5 mm), a longer wheelbase (+4 mm), the same chainstay length, a slightly higher stack (+2 mm), the same head tube angle, and a 0.5° steeper seat tube angle.
Why not more radical?
With increasingly extreme aero bikes appearing on the market, such as the Factor One, we asked Giant whether it had considered pushing the Propel further in that direction.
Giant’s Nixon Huang was clear: “It’s not a bike we want to create and it’s not a bike that WorldTour riders will appreciate.”
He explains that while the aero bike is now the primary choice for WorldTour racers, it still has to deliver more than outright wind-tunnel numbers:
“The aero bike is the main choice for WorldTour racers, so this bike is not just aero but also very good in control, very good stiffness for cornering, sprinting, and also comfortable enough for a long day riding.”
He added that while Giant likely has the capability to build something more radical, it’s simply not the brand’s direction. “We shouldn’t go that extreme. I believe that with our capabilities we can do it better than everybody, but that’s not the direction we want.”
Huang also pointed to the company’s broader philosophy, referencing founder King Liu’s vision that Giant should remain a brand that “offers more people on bikes,” rather than pursuing ultra-extreme designs.
Where does that leave the TCR?
According to Nixon Huang, the Propel Advanced SL will be the bike of choice for Jayco AlUla’s WorldTour riders in virtually all races this season. He describes it as an “all-round race bike” that still serves as Giant’s dedicated aero platform.
That inevitably raises questions about the TCR. Long positioned as Giant’s lightweight climbing bike, the TCR now sits alongside a Propel that is only marginally heavier, yet significantly more aerodynamic. With aero bikes increasingly brushing the UCI’s 6.8kg minimum weight limit, the performance gap between aero and all-round bikes is narrowing.
> Lightest road bikes
So, where do Giant see the TCR going?
“I don’t think I have a perfect answer for that,” Huang admits. He points out that globally the TCR still outsells the Propel overall, with stronger demand in some Asian markets, while Europe and the US lean more toward the Propel model.
Huang also acknowledges that regulation plays a major role:
“I think mainly because the [UCI’s minimum] weight limitation of 6.8kg… If you cannot lower the weight, make it more aero. But what if the rule changes one day? We still have a good TCR that is even lighter and still has a very good stiffness-to-weight ratio. Probably we can improve the aerodynamics a little bit, but how to find a balance, I don’t have the answer now.”
First ride impressions of the EnviLiv
I spent some time out in Nice riding the new top-tier Liv EnviLiv Advanced SL over 88km and 1,700m of climbing. Climbing well isn’t just about saving grams but the EnviLiv handles climbs impressively, not like older aero bikes that favoured straight-line speed over all-round performance.
Giant said they focused on instant speed, sustained speed and top-end speed and the EnviLiv certainly had the first in abundance. I spent much of the ride trying to pinpoint what this was down to and concluded that the low rotational weight of the carbon spoked wheels and Cadex race tyres were big contributors. Carbon spoked wheels are more expensive but can often save around 50g per wheel. Combine this with Cadex’s one-piece hub/spoke design and you’re treated to impressive lateral stiffness which will surely be welcomed by riders with higher sprint power than me. However, carbon spokes can often feel harsh but this wasn’t the case here. When I get the chance to test the bike in the UK, I will be sure to switch between different wheelsets and tyres to isolate the frame.
The EnviLiv feels responsive, with quick steering. What goes up must come down and so despite just a few rides on the new bike I had plenty of time to get acquainted with the handling but I will need to test it further on our home roads in the UK.
Power transfer is direct, there’s minimal movement at the bottom bracket when you’re cranking out the power, and the front end feels equally tight, even during out-of-the-saddle sprints or when pushing hard into corners. I love a sprint!
Despite its stiffness, the EnviLiv feels surprisingly comfortable – and not just compared to other aero bikes. I’m used to a Specialized SL6, and this felt as smooth as an all-round road bike. Over 88 km and 1,700 m of climbing in Nice, the frame and fork absorbed bumpy road surfaces well.
I was riding on 28mm tyres and the integrated cockpit also seemed to take the edge off harsher bumps. It’s a noticeable step on from earlier generations of aero bikes, including previous Propels, which had a reputation for feeling quite unforgiving. Giant addressed much of that harshness with the last Propel update.
It’s another example of how modern aero bikes no longer demand the same trade-offs they once did. Where aerodynamic gains used to come at the expense of comfort or versatility, bikes like the EnviLiv show that balance is now much easier to achieve.
The riding position of the EnviLiv is aggressive, but not too extreme. There’s not many test bikes that come set-up in a way in which I’m comfortable with. Many performance cyclists, but especially women and smaller riders are often left wanting with stock component choices, something that can lead to great additional expense when purchasing a new bike. The medium test bike came with 37mm wide handlebars as standard, which is sensible. Crank lengths are also well considered. The medium uses 170mm cranks, while the XS and S sizes are specced with shorter 165mm cranks.
The men’s Propel also seems to have gone some way in bringing handlebar width and crank length in line with the focus of the bike. – speed.
Unlike the Propel Advanced SL, the top-tier EnviLiv Advanced SL isn’t offered with Shimano’s Dura-Ace groupset. Instead, the range tops out with SRAM Red, while lower models are available with Shimano Ultegra Di2. Engineers say the choice comes down to ergonomics, with SRAM’s shifter design better suited to smaller hands, and I found the SRAM setup comfortable.
Models, pricing and availability
Each frameset is available in various builds:
Giant Propel Advanced SL 0 (£10,499)
Groupset SRAM Red AXS
Wheels Cadex 50 Max WheelSystem
Giant Propel Advanced SL 0 (£9,999)
Groupset Shimano Dura-Ace Di2
Wheels Cadex 50 Max WheelSystem
Giant Propel Advanced Pro (£6,749)
Groupset Shimano Dura-Ace Di2
Wheels Giant SLR 0 50 WheelSystem
Giant Propel Advanced Pro 0 (£5,999)
Groupset SRAM Force AXS
Wheels Giant SLR 0 50 WheelSystem
Giant Propel Advanced Pro 0 (£5,799)
Groupset Shimano Ultegra Di2
Wheels Giant SLR 0 50 WheelSystem
Giant Propel Advanced Pro 1 (£4,599)
Groupset Shimano 105 Di2
Wheels Giant SLR 1 50 WheelSystem
Giant Propel Advanced 0 (£4,199)
Groupset Shimano Ultegra Di2
Wheels Giant SLR 2 50 WheelSystem
Giant Propel Advanced 1 (£3,499)
Groupset Shimano 105 Di2
Wheels Giant SLR 2 50 WheelSystem
Giant Propel Advanced 2 (£2,599)
Groupset Shimano 105
Wheels Giant P-A1 wheelset 38mm deep
Despite Giant designing the latest Propel as a whole system, you can also get the Advanced SL and Advanced Pro as framesets, priced at £3,799 and £2,199, respectively.
The Liv follows the exact same pricing structure as the Propel, except for one difference in that the lowest tier EnviLiv Advanced 2 costs £2,499, whereas the Propel Advanced 2 costs £2,599.
For more information, head over to Giant’s website and liv-cycling.com
road.cc travelled by train to attend the press event for this product launch in line with our no-fly policy. You can read more about why we do this here