CyclistNew Giant Propel steals TCRs clothes with lighter one-piece construction and high-performance Cadex componentsGiant claims the new Propel is the lightest and fastest version of its aero road bike, with top-tier builds weighing as little as 6.5kg while improving efficiency by 18.4 watts over the old bike.First released in 2013 as an all-out aero bike, the Propel has steadily morphed into Jayco-AlUlas default WorldTour race bike at the expense of the TCR. With its fusion of low weight and drag, the Propel now looks to challenge the likes of the Specialized Tarmac SL8, Trek Madone SLR and Cannondale SuperSix Evo in the all-round road race bike category.In keeping with its conservatism, Giant has eschewed the bayonet forks and oversized head tubes adopted by some aero bike designers. Apart from dropped seatstays and a more streamlined front-end, the Propels truncated ellipse aerofoil shapes are nearly the same as its predecessors.Since the last generation, our finding was that if you go pure aero, you reduce your fan base, says Nixon Huang, Giants road category manager. Most consumers need a bike for almost any kind of riding, not just the flat but rolling hills, even climbs.All three tiers of the Propel benefit from new components that are claimed to be faster and lighter. The Advanced SL tops the range at 10,499 / 11,999 / $13,500 / AU$15,999. The entry-level Advanced costs 2,599 / 2,999 / $3,500.Whats changed?New single mould front triangle shaves 40g off frameset355g total weight reduction18.4 watts in efficiency savingsDropped chainstays, thinner head tube and forkUDH rear dropoutMore front-end and rear-end compliance32mm tyre clearanceWhat hasntMost frame shapesGeometryOversize 1 1/4in steererIntegrated Seatpost on Advanced SLTotal speed systemBy addressing the efficiency of every component, first through computational fluid dynamics and then wind tunnel testing, Giant claims it has made the new Propel Advanced SL 72 seconds faster over 40km at 40kmh than before though obviously thats impossible as 40km at 40kmh would take an hour no matter how aero or unaero the bike is.Looking beyond that and purely at equivalent time saving over that distance at the same power than the theoretical previous effort, that sounds like a dramatic improvement. But when you consider that the previous version came out in 2022 and left low-hanging fruit in the form of a two-piece cockpit and relatively slow tyres to improve on, it seems more feasible.Giant says it hasnt tested the latest Propel against other brands bikes. But it claims that using a pedalling mannequin in the wind tunnel makes its aero testing against the old Propel more accurate. Giant mechanic Andy Wollony, who designed Grischa 2.0, a 3D-printed model rider costing 5,000, says this reduces the margin of error to 0.5 watts compared to the three watts typical of real-rider testing.Giant says it placed Grischa 2.0 on size medium frames. As its legs pedalled, engineers measured linear aero drag and wheel rotating drag at 40kmh over -20 to +20 yaw angles, and rolling resistance at 40kmh under a 42kg load per tyre.The averages of these three measurements were then added together to calculate total system resistance. This was 267.76 watts for the old bike versus 249.32 watts for the new one.Giant says most of these savings come from the components, so it follows that the old frame with the new parts could be nearly or as fast as the new one. The 42cm width of the old Propels handlebar in this test looks distinctly disadvantageous compared to the new aero bar measuring 37cm at the hoods.This doesnt appear to be a stock width, but Giant does offer the one-piece Contact SLR Aero O cockpit in an extensive size range: 3608090mm, 38080140mm, 40090140mm, 42090120mm and 440100120mm.With a claimed weight of 286g in the 420x100mm size, the Contact SLR Aero 0 saves 74g over the previous separate bar and stem. It has a negative 10 stem angle and lengthy reach to facilitate the aero hoods position, a shallow drop to ease the transition to drops and slight flare for stability.Cadex claims the star-shaped aero flanges of the Cadex Max 50 WheelSystem and integrated, bladed carbon spokes cut drag by 2.4 watts compared to the Ultra 50.Designed specifically for these wheels, the updated Cadex Aero tyre uses a more supple casing than before, up from 170tpi to 240tpi, to reduce weight by 55g per tyre and rolling resistance by 2.8 watts in total.Despite introducing tube-specific aero bottle cages on the last Propel, Giant hasnt followed the trend for proprietary aero bottles.Racers grab bottles that are regular bottles, says Giants global product marketing manager, Andrew Juskaitis.So we do have to think about airflow from the wheel over the fork and down tube as well, and how it flows over a regular water bottle. Some integrated aero bottles can be a lot faster, but its just not real. Related Posts Inside Giant's Taiwan factory Giant TCR Advanced Pro road bike review Best road bikes 2026 ridden and reviewed Best aero road bikes 2026 reviewed Minor frame changesThe standout change is to the seatstays, which are now dropped to increase seated compliance by 25%, as requested by Jayco-AlUla riders. Lower seat stays are generally more comfortable because they enable the seat tube and seatpost to flex more. In this case, they also accommodate wider tyres, increasing clearance to 32mm, which the slimmer fork makes possible at the front too.Asked why Giant settled on the squared off shape of the stays, Huang says, Thats more complicated to explain because the riders legs are moving and the wheel is spinning at 40kmh, so that pulls some of the airflow to the front. But also the majority of the air has collapsed around this area so we tried all different shapes to optimise and reduce the drag.You have to look hard to notice minor changes to the front of the bike. Brake calipers are more neatly hidden behind the thinner and sharper edged fork, and the head tube tapers back a touch more sharply, reducing frontal area in order to smooth airflow over the wheel hub.The narrower head tube still leaves room for cables to pass, either through or under the handlebar, beneath the stem and in front of the D-shaped fork steerer into the frame. This semi-integrated design leaves a cable access slot to simplify servicing and routing.One-piece mouldFor the first time, Giant has made the front triangle of the Propel from one piece of carbon fibre from a single bladder or mould, as it did on the latest TCR. Previously the Propel was made from three separate moulds.The frameset weight reduction came mainly from the one-piece molding for the frame, says Huang. Because we can make the whole carbon layer from one piece, there are no joints.Its several frame pieces, the head tube, top tube and down tube, joined together, so theres some overlap with this kind of one-piece moulding. But it allows the engineer to design the layout continuously with no wasted material.The range-topping Advanced SL keeps Giants divisive integrated seatpost. While admitting that the necessity to cut it to your saddle height makes it a pain in the ass for travel and can reduce resale value, Juskaitis says, This is an engineered part of the frame from the tip all the way to the bottom, and so we can engineer flex, and stiffness from side to side. Were still committed to it because you save so much weight and we offer so much compliance.Stiffer but more stableAlthough Giant set out to maintain stiffness, the brand says the framesets torsional and pedalling stiffness are up by 3.4% and 2.4% respectively.With the one piece moulding technology we learned from the TCR and by updating the layup with the latest fibres and technology, we created a really good result by reducing the weight by a lot and also increasing the stiffness a little bit, says Huang.While admitting that the Propels bottom bracket stiffness is nearing the limit of what is desirable in terms of pedalling efficiency, Juskaitis says, With stiffness comes control.The Propel development team also tried to improve the bikes front-end control, as measured by its predictable torque curve where a straighter line translates into more predictable handling, according to Giant.Especially in Taiwans gusty winter conditions, Huang says, We need to address how we can manipulate the frame profile to have really good control during heavy crosswinds. Particularly for this generation, the line of the wind tunnel result is more straight. So I would say that the overall crosswind effect is smaller than many of our competitors.What about the TCR?At the launch, Giant said its mens WorldTour team, Jayco-AlUla, will almost exclusively race the Propel in 2026. In reality, this was true for the previous generation with the exception of certain Grand Tour mountain stages Chris Harper rode a TCR to victory atop the Colle delle Finestre on Stage 20 of last years Giro dItalia.Nonetheless, Giant continues to make both bikes, unlike some of its rivals who have consolidated their road race range into one model. Its rationale is partly to insure against a decrease in the UCI weight limit.Most WorldTour teams ride aero bikes because of the 6.8kg limitation, says Huang. But if one day the UCI changes the rule to 6.2 or 6.4kg, its a different story.The other reason is financial. We still have good sales for both bikes, adds Huang. Last year we still sold more TCRs than Propels 30% more, not dramatically more, so even the current Propel is still really good business. So that gives us enough resources and confidence to evolve the next generation TCR.Trickle downThe models most consumers will be looking at buying are the second-tier Propel Advanced and entry-level Advanced, due to their lower prices and separate, adjustable seatposts. They share the Advanced SLs modestly tweaked frame shape.Because their modified monocoque construction involves more material from lower grade carbon and resin, which is cut less precisely and coated in thicker paint, their Advanced composite is heavier and less stiff.Frameset weightsTo calculate its frameset weights, Giant included the frame, fork and necessary hardware and compared them to the previous generation Advanced SL.Advanced SL 1,443g down 40gAdvanced Pro 1,569g up 85gAdvanced 1,619g up 135gIn addition, Giant supplies weights for the transmission system, essentially the bike minus the groupset.Advanced SL 3,515g down 355gAdvanced Pro 3,770g down 100gAdvanced 4,568g up 698gThe cheaper Propel builds also have upgraded components. The Advanced Pro gains the integrated Contact SLR 1 cockpit, which shares the SLR 0s geometry, and new Giant SLR 0 WheelSystem. These 50mm deep rims use carbon spokes to reduce weight to 1410g, according to Giant, and have fast-engaging 40-tooth hubs. They are wrapped in Cadex Aero tyres.On Advanced builds, Giant specs its SLR 50 1 WheelSystem, which shares the SLR 0s carbon layup but has steel spokes for a claimed weight of 1500g. The brand fits its new Gavia Course, pitched as a fast-rolling, but reliable tyre.The entry-level Propels cable routing is semi-internal under the new Contact SL Aero handlebar and stem.Geometry and sizingXSSMMLLXLSeat tube length484505528.5554576595Seat tube angle (degrees)74.5074.0073.5073.0073.0072.50Top tube length520535550565580600Head tube length115127145165185200Head tube angle (degrees)71.572.573.0073.0073.0073.00Fork rake454545454545Trail67.861,458.358.358.358.3Wheelbase97197398099010061020Chain stay length405.0405.0405.0405.0405405Bottom bracket drop72.072.069.569.567.067Stack515530546565582596Reach377383388392402412Stand over height746764787808832847Handlebar width380380400400420420Stem length8090100110110120Crank length165.0165.0170.0170.0172.5172.5Wheel size700C700C700C700C700C700CThe Propel retains its racy geometry characterised by a longish and very low front-end, and short trail, wheelbase and chainstays for reactivity.Giant has dropped the bottom bracket by 4mm and steepened the head angle in sizes XS and S, capitalising on shorter cranks lowering the risk of pedal strikes and toe overlap.That helps us to have a better geometry for extra small and small [sizes] by having more steering control. A lower bottom bracket is always more stable, says Huang. We also shortened the head tube length to keep the same stack height.The six sizes should ensure most riders can find a well-fitting frame, but you probably wont be able to change component sizes prior to purchase online. A bricks-and-mortar Giant dealer may accommodate requests for swaps.Giant Propel 2026 range and specsThe Propel Advanced-level framesets are compatible with mechanical Shimano shifting, but the Advanced SL frameset only works with electronic shifting.Giant Propel Advanced 2Price: 2,599 / 2,999 / $3,500 / AU$ N/AColour: Gloss White with BlackFrame: Advanced-grade compositeFork: Advanced-grade compositeGroupset: Shimano 105 mechanical 212Bars: Giant Contact SL AeroStem: Giant Contact SL Aero, -10Seatpost: Giant Vector CompositeSaddle: Giant Fleet SLWheels: Giant P-A1Tyres: Giant Gavia Course 0, 700x28cGiant Propel Advanced 1Price: 3,499 / 4,399 / $5,300 / AU$5,999Colour: Satin Carbon SmokeFrame: Advanced-grade compositeFork: Advanced-grade compositeGroupset: Shimano 105 Di2Bars: Giant Contact SL AeroStem: Giant Contact SL Aero, -10Seatpost: Giant Vector CompositeSaddle: Giant Fleet SLWheels: Giant SLR 2 50 WheelSystemTyres: Giant Gavia Course, 700x28cGiant Propel Advanced 0Price: 4,199 / 4,799 / $N/A / AU$N/AColour: Glozz Azuraite BlueFrame: Advanced-grade compositeFork: Advanced-grade compositeGroupset: Shimano Ultegra Di2Bars: Giant Contact SL AeroStem: Giant Contact SL Aero, -10Seatpost: Giant Vector CompositeSaddle: Giant Fleet SLWheels: Giant SLR 2 50 WheelSystemTyres: Giant Gavia Course, 700x28cGiant Propel Advanced Pro 1 Di2Price: 4,599 / 4,999 / $N/A / AU$6,999Colour: Satin Cryo SilverFrame: Advanced-grade compositeFork: Advanced SL-grade compositeGroupset: Shimano 105 Di2, Giant Power Pro power meterBars: Giant Contact SLR 1 Aero IntegratedSeatpost: Giant Vector CompositeSaddle: Giant Fleet SLWheels: Giant SLR 1 50 WheelSystemTyres: Giant Gavia Course, 700x28cGiant Propel Advanced Pro 0 AXSPrice: 5,999 / 6,499 / US$7,800 / AU$9,099Colour: Gloss Obsidian PulseFrame: Advanced-grade compositeFork: Advanced SL-grade compositeGroupset: SRAM Force AXS, power meterBars: Giant Contact SLR 0 Aero IntegratedSeatpost: Giant Vector CompositeSaddle: Giant Fleet SLWheels: Giant SLR 0 50 WheelSystemTyres: Cadex Aero, 700x28cGiant Propel Advanced Pro 0 Di2Price: 5,799 / 6,499 / $N/A / $8,499Colour: Gloss Obsidian PulseFrame: Advanced-grade compositeFork: Advanced SL-grade compositeGroupset: Shimano Ultegra Di2Bars: Giant Contact SLR 0 Aero IntegratedSeatpost: Giant Vector CompositeSaddle: Giant Fleet SLWheels: Giant SLR 0 50 WheelSystemTyres: Cadex Aero, 700x28cGiant Propel Advanced Pro Dura AcePrice: 6,749 / 7,999 / $8,000 / AU$10,499Colour: Gloss Supernova with Tactical GreyFrame: Advanced-grade compositeFork: Advanced SL-grade compositeGroupset: Shimano Dura-Ace Di2Bars: Giant Contact SLR 0 Aero IntegratedSeatpost: Giant Vector CompositeSaddle: Giant Fleet SLWheels: Giant SLR 0 50 WheelSystemTyres: Cadex Aero, 700x28cGiant Propel Advanced Pro framesetPrice: 2,199 / 2,699 / $3,200 / AU$N/AColour: Satin Glacier TealFrame: Advanced-grade compositeFork: Advanced SL-grade compositeSeatpost: Giant Vector CompositeGiant Propel Advanced SL 0 RedPrice: 10,499 / 11,999 / $13,500 / AU$15,999Colour: Gloss Superspeed BlueFrame: Advanced SL-grade composite, Integrated seatpostFork: Advanced SL-grade compositeGroupset: SRAM Red AXSBars: Giant Contact SLR 0 Aero IntegratedSaddle: Cadex AMPWheels: Cadex 50 Max WheelSystemTyres: Cadex AeroGiant Propel Advanced SL 0 Dura-AcePrice: 9,999 / N/A / $N/A / AU$14,499Colour: Gloss Prizm PearlFrame: Advanced SL-grade composite, Integrated SeatpostFork: Advanced SL-grade compositeGroupset: Shimano Dura-Ace Di2Bars: Giant Contact SLR 0 Aero IntegratedSaddle: Cadex AMPWheels: Cadex 50 Max WheelSystemTyres: Cadex AeroGiant Propel Advanced SL framesetPrice: 3799 / 3,899 / $5,000 / AU$4,999Colour: Gloss Cyber SunsetFrame: Advanced SL composite, Integrated seatpostFork: Advanced SL compositeThe post New Giant Propel steals TCRs clothes with lighter one-piece construction and high-performance Cadex components appeared first on Cyclist.