mountainbike mercury aero tubing Cervelo R5 Force eTap AXS Road Bike

The Cervelo R5 Force AXS Bike is Cervelo's pure climbing race bike — the machine Jonas Vingegaard rode to back-to-back Tour de France victories in 2022 and 2023. That pro pedigree isn't incidental to the product. The R5 was shaped by Visma-Lease a Bike's demands for a bike that climbs as efficiently as possible: 651 grams for the frame in size 56, 298 grams for the fork, and a ride character that's consistently described as direct, lively, and genuinely effortless on long mountain efforts. The Force AXS build puts the R5 platform within reach of more riders without changing what the chassis does or how it feels.

Cervelo builds the R5 frame using FEA-optimized carbon layup, with each ply individually placed and oriented to match the specific load paths of a climbing race bike. The frame uses Squoval Max tubing — a hybrid between square and oval cross-sections that improves the stiffness-to-weight ratio and vertical compliance compared to round or purely square profiles. The bottom bracket shell is BBright: Cervelo's asymmetric 79mm press-fit shell with an 11mm offset on the non-drive side that positions the bearing closer to the crank for improved stiffness without affecting pedal stance width. The seatstay junction was refined specifically for increased vertical compliance, and the D-shaped SP33 seatpost runs with meaningful exposed length to take further edge off rough tarmac without flex in the pedaling plane. Total frame and fork weight comes in at 949 grams in size 56.

SRAM Force eTap AXS handles shifting wirelessly across 12 speeds with a 48/35 chainring combination and a 10-33T cassette. Fully wireless, fully electronic — no cables to route through the integrated cockpit, no mechanical indexing to drift. Reserve 34|37 carbon wheels run a 34mm front and 37mm rear rim depth, with a 1,300g wheelset weight and center-lock disc hubs. The asymmetric rim depth is a considered choice for a climbing bike: the deeper rear contributes aerodynamically on flats and descents while the shallower front stays manageable in crosswinds on exposed mountain roads. Vittoria Corsa Pro Speed TLR in 700x26c run tubeless on that rim.

Design Benefits

1. The Frame Is the Story. At 651 grams in size 56, the R5 frame sits among the lightest production carbon road frames available. Cervelo achieves that number through FEA-driven carbon ply placement — each layer oriented for the specific load it carries rather than applied uniformly — combined with Squoval Max tube profiles that squeeze more stiffness and compliance from less material than round sections allow. The result is a chassis that transfers pedaling power with near-zero flex and returns that energy on climbs where cadence and wattage are at their peak. This is the same frame Visma-Lease a Bike races at the Tour de France. The groupset spec changes between builds; the frame doesn't.
2. BBright Solves a Real Engineering Problem. Most road bikes use a symmetric bottom bracket shell. BBright shifts the non-drive side bearing 11mm outboard, positioning it closer to the crank axle and dramatically increasing the lateral stiffness of the drivetrain interface. Pedaling efficiency improves — especially under the sustained high-torque efforts climbing demands — without widening the Q-factor or changing how the bike fits. It's one of several engineering decisions on the R5 that prioritize measurable performance gains over manufacturing simplicity.
3. Force eTap AXS Is Excellent Wireless Electronic Shifting. SRAM Force eTap AXS uses the same wireless system architecture as Red AXS — the same shift logic, the same AXS app integration, the same brake lever feel. Force is heavier by a few hundred grams across the full build and finished to a slightly lower specification. On a frame where the chassis and wheels carry the performance story, that trade-off makes sense. The $4,000+ difference between this build and the Red AXS spec buys a finer groupset, not a better-riding bike. The R5 Force AXS is not a compromised version of the R5 — it's a thoughtfully priced one.
4. Reserve 34|37 Wheels Are Purpose-Built for This Application. The asymmetric rim depths — 34mm front, 37mm rear — reflect how aerodynamics and handling interact differently at each end of the bike. The rear wheel sits in a more aerodynamically favorable position and benefits from additional depth. The front wheel affects steering precision and crosswind sensitivity, where a shallower rim is more manageable. At 1,300 grams for the pair, tubeless-ready with XDR freehubs and center-lock disc mounts, the Reserve 34|37 is a performance wheelset matched to the ambitions of the frame.

Final Take

The R5 is a specific bike for a specific purpose: climbing, racing, and riding fast on roads where weight and pedaling efficiency determine the outcome. It doesn't pretend to be an endurance bike or an all-road machine — the 34mm maximum tire clearance and pro-fit geometry tell you exactly what it's designed for. Within that purpose, it's as good as road bike engineering gets. The Force AXS build is the right starting point: wireless electronic shifting, a genuinely strong wheelset, and the same carbon frame that wins major races. If you're ready to ride a bike built around what it means to climb well, the Cervelo R5 Force AXS is the answer.