Aero highway bikes have come a good distance over the previous decade. What began as wind-tunnel specialists, typically brutally stiff and never precisely forgiving on actual roads, has advanced into one thing far more refined. The most recent technology of the Big Propel exhibits simply how far the class has progressed.
With the launch of the all-new Propel vary, Big is specializing in what it calls a “complete pace system,” treating the rider, body, cockpit, wheels, and tires as a unified aerodynamic platform. They needed a motorcycle that’s not simply quick in managed testing however quick in all places. Meaning on the flats, over climbs, and throughout the tough pavement that defines actual racing, principally a motorcycle that can do every thing. Simple proper?
A Decade of Propel Growth
The Propel story begins within the early 2010s, when aero highway bikes have been turning into the subsequent massive frontier in race efficiency. Big designed the unique Propel with sprinting in thoughts, giving riders like Marcel Kittel and John Degenkolb an aerodynamic benefit when the speeds ramped up. Kittel famously rode the bike to victory on Stage 1 of the 2014 Tour de France, pulling on the yellow jersey aboard the first-generation machine.
The early Propel was unapologetically aero. Deep airfoil tubes and aggressive shaping prioritized drag discount above all else. It was met with some pleasure and loads of side-eye, particularly whenever you requested for a brake adjustment.
In 2018, the platform noticed its first main overhaul. Disc brakes have been added, and Big launched its AeroSystem Shaping engineering course of — an method that evaluates the bike and rider as a single aerodynamic unit reasonably than optimizing particular person elements in isolation.
That idea has formed each technology since.
The third iteration debuted on the 2022 Tour de France and rapidly proved its versatility. Riders from Workforce Jayco-AlUla, together with Dylan Groenewegen and Michael Matthews, scored victories on the bike — demonstrating that it might win each flat bunch sprints and demanding hilly levels.
Now the most recent technology arrives with a improvement focus constructed round three varieties of pace.
High-Finish Velocity, Immediate Velocity, Sustained Velocity
The event temporary for the brand new Propel centered on three efficiency targets: top-end pace, on the spot acceleration, and sustained effectivity.
High-end pace focuses on minimizing aerodynamic drag when riders are pushing excessive speeds on flat terrain. Immediate pace refers to responsiveness when sprinting or attacking. Sustained pace is about effectivity and luxury throughout lengthy efforts.
By approaching the bike as a full system, body, cockpit, wheels, and tires working collectively, Big claims the brand new Propel reduces complete resistance by 18.44 watts in comparison with the earlier technology. However that’s all of the components working collectively, together with the newly up to date CADEX Max 50 wheelsystem and Aero Tire.
At 40 km/h, that equates to roughly 72 seconds saved over a 40-kilometer effort.
Wind Tunnel Growth and Grischa 2.0
One of many extra attention-grabbing components of Big’s aero improvement program includes a dynamic wind-tunnel model named “Grischa”. We even bought to satisfy Grischa, and let me inform you, dude can experience. He by no means will get drained and doesn’t complain. These attributes make him the proper aero check topic, and he was crafted from the size of an actual human rider.
The model was initially created from a 3D scan of former skilled rider Grischa Niermann. Not like conventional wind-tunnel mannequins, it options articulated legs and lifelike pedaling movement, permitting engineers to simulate airflow round a transferring rider. That issues as a result of the rider accounts for a good portion of aerodynamic drag.
The most recent model, Grischa 2.0, provides improved body-shaping and modular elements, enabling engineers to check totally different helmets, rider positions, and airflow patterns with larger accuracy.
Utilizing this technique, Big engineers evaluated lots of of configurations earlier than arriving on the remaining manufacturing design.
Built-in Aero Design
Integration performs a significant function within the new Propel’s efficiency. On the entrance finish, the bike makes use of a one-piece built-in cockpit with Big’s Contact SLR Aero handlebar and stem (totally different from the CADEX handlebar and stem reviewed right here). The bar options flattened tops and narrower widths to scale back the rider’s frontal space whereas bettering airflow across the shoulders.
Cables are routed internally via the cockpit and body to get rid of uncovered strains and additional scale back aerodynamic drag. The pinnacle tube additionally receives a redesign via Big’s OverDrive Aero system, which pairs a slim tapered head tube with a D-shaped steerer tube and aerodynamic spacers.
Additional aerodynamic positive aspects come from Big’s aero wheel methods and CADEX Aero tires. The tire-to-rim interface is optimized to easy airflow and scale back rolling resistance, serving to riders keep pace throughout various wind angles.
Even the bottle cages are formed particularly for the body to attenuate drag, plus they take a regular-size bottle.
Lighter and Stiffer
Regardless of its aerodynamic focus, the brand new Propel additionally manages to shed weight.
The flagship Superior SL frameset is 45 grams lighter than the earlier technology. When factoring within the new cockpit, wheel system, and different part refinements, the top-tier Propel Superior SL 0 drops about 355 grams total.
Stiffness additionally improves. Testing exhibits a 3.4 p.c enhance in torsional stiffness and a 2.4 p.c enhance in pedaling stiffness. Mixed with the lowered weight, this ends in a 5.7 p.c enchancment within the stiffness-to-weight ratio.
In sensible phrases, meaning sharper acceleration and extra environment friendly energy switch when riders bounce out of corners, bridge as much as a transfer, or launch a dash – irrespective of if for the win or the city line.
Driving Actual Roads
Trendy aero bikes can’t depend on pure stiffness alone; their viewers isn’t solely the world tour professionals and U23 superhumans. Consolation and effectivity over lengthy distances are equally necessary. The brand new Propel addresses this with improved body compliance and bigger tire clearance.
A redesigned rear triangle and seatpost enhance vertical compliance by as much as 25 p.c in comparison with the earlier technology, serving to scale back highway vibration and rider fatigue. The rear triangle drops barely in comparison with the earlier mannequin, and the toptube is horizontal reasonably than compact.
Up entrance, the built-in cockpit provides roughly 12.8 p.c extra compliance to easy out highway buzz. That compliace comes from the bars, however not the body.
The body and fork now enable tire clearance as much as 32mm, giving riders the choice to run bigger tires at decrease pressures for improved grip and lowered rolling resistance on tough pavement.
Composite Development
The Propel vary is constructed utilizing Big’s Superior and Superior SL composite applied sciences.
The highest-tier Superior SL fashions use professional-grade carbon fiber mixed with Carbon Nanotube resin expertise, which reinforces the construction and improves affect resistance by about 14 p.c. The frames are produced utilizing one-piece molding strategies that kind the entrance triangle as a steady construction, decreasing weight whereas bettering stiffness and sturdiness. This is similar molding that Big makes use of of their up to date Anthem SL and X framesets.
Further manufacturing processes, corresponding to cold-blade carbon slicing, enable Big to supply extra exact carbon layups whereas minimizing extra materials.
Big Propel Gen 4 – Sizing and Geometry
The brand new Big Propel Gen4 vary is on the market in six body sizes: XS, S, M, ML, L, and XL.
Further key geometry figures:
Chainstay size: 405 mm
Fork rake: 45 mm
Backside bracket drop: 67–72 mm, relying on dimension
Tire clearance: as much as 32 mm
Wheel dimension: 700c throughout all fashions
Big Propel Gen 4 Pricing
Propel Superior SL Collection
Propel Superior SL 0 (Dura-Ace Di2) – $15,899 CAD
Propel Superior SL 0 (SRAM RED AXS) – $13,500 USD / €11,999 / $16,899 CAD
Propel Superior Professional Collection
Propel Superior Professional 0 AXS – $7,800 USD / €6,499 / $9,499 CAD
Propel Superior Professional 1 – €4,999
Propel Superior Collection
Propel Superior 0 – €4,799 / $6,499 CAD
Propel Superior 1 – $5,300 USD / €4,399 / $5,999 CAD
Propel Superior 2 – $3,500 USD / €2,999 / $3,899 CAD
What Does This Imply For the Big TCR?
That’s the very first thing I believed as I pulled the Big Propel SL 0 from the rack for a check experience. It was very gentle and overlapped with the TCR to an honest extent, particularly with the up to date compliance. Heck – the sponsors, Jayco World Tour Groups, might be using the brand new Propel for many of their races.
However Big says the TCR will at all times have a spot within the Big lineup. When the highway factors up, the TCR is the bike that the climbers need, and never simply the world tour execs, which suggests masters, amateurs, and everybody who likes to climb. It’s nonetheless fairly wild how shut the 2 are coming in efficiency and using suggestions. It will likely be a tough alternative for many when hitting the Big seller for his or her subsequent highway bike.
Availability – Big Propel
The brand new Big Propel might be obtainable in all areas. The continued state of affairs with Big and the CBP and WRO has left the Propel Superior SL fashions and a few elements unable to enter the USA for distribution till the difficulty is resolved.
We requested Big concerning the ongoing state of affairs, they usually defined, “Big Group reiterates that it’ll uphold the rules of integrity, transparency, and concrete motion, proceed to totally help CBP’s overview course of, advance all corrective measures, and pursue the well timed lifting of the WRO.”
You may verify the standing of the method and Big’s progress on the Big press web site right here.
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