Cervelo R5 Red XPLR AXS 1 E1 Bike

The Cervelo R5 Red XPLR AXS 1 E1 is what Cervélo builds for mountain stages at the Tour de France and the Vuelta — a carbon road bike reduced to its essential purpose: going uphill faster than anything else. The complete bike weighs 5.97 kilograms at size 56. That’s 900 grams under the UCI’s 6.8kg minimum weight limit, which means professional riders have to add ballast before they can race it legally. For everyone else, it’s a straightforward performance advantage on every climb you ride.

The frame is 651 grams. The fork is 298 grams. These are figures achieved through premium carbon construction and Cervélo’s engineering focus on the one thing that defines the R5: stiffness-to-weight ratio optimized specifically for climbing. The geometry is aligned with Cervélo’s S5 aero platform, so riders who switch between both bikes don’t need to relearn how either one handles. Chainstay length is fixed at 410mm across all sizes, giving the bike consistent handling character regardless of which size you’re on. Tire clearance runs to 34mm — enough to run wider rubber on rough descents without compromising the race-oriented geometry.

The build is centered on SRAM Red XPLR AXS, a 1x13-speed wireless electronic groupset designed specifically for maximum range with minimum complexity. The 48T aero chainring paired with a 10-46T cassette gives you a wider gear spread than a traditional road double, without a front derailleur to manage. The Red XPLR crankset includes an integrated single-sided power meter — no separate unit, no additional weight, no bolt-on compromise. Hydraulic disc brakes with Paceline X centerlock rotors round out the drivetrain. Everything communicates wirelessly; the cockpit stays clean.

The HB18 integrated one-piece carbon bar and stem was co-developed with Cervélo’s engineering team to shed nearly 150 grams versus the previous generation cockpit while improving aerodynamic efficiency by two watts at race speed. It comes in 15 size combinations, so fit is dialed without requiring custom components or aftermarket substitutions. The Reserve 34|37 SL wheelset — 34mm front, 37mm rear — pairs DT Swiss 180 hubs with Reserve’s refined carbon layup for a tubeless-ready setup that balances aerodynamic depth with crosswind stability on technical mountain descents. Vittoria Corsa Pro Speed TLR tires in 26mm complete the rolling package. The build also includes a Hammerhead Karoo 3 GPS computer with front and rear mounts — everything you need from day one.

Design Benefits

1. 5.97kg Race Weight: At 900 grams under the UCI minimum, the R5 is among the lightest production road bikes available. That number is meaningful — it represents the difference between a bike that feels effortless on a long climb and one that simply doesn’t. Where professionals add ballast to comply with race rules, amateur riders ride the full advantage.
2. SRAM Red XPLR 1x13 with Power Meter: The 1x13 XPLR drivetrain eliminates front shifting complexity while delivering a gear range wider than a traditional double — 10-46T cassette covers everything from Alpine descents to 15% gradients. The integrated power meter removes the only real argument against running 1x on a race bike: you still have complete training data, no additional hardware required.
3. HB18 Integrated Carbon Cockpit: Cervélo’s co-developed one-piece bar and stem saves approximately 150 grams and two aerodynamic watts compared to the previous generation, while the 15 available size combinations ensure proper fit rather than forcing a compromise. Internal cable routing keeps the front end clean from lever to fork crown.
4. Reserve 34|37 SL Wheelset with DT Swiss 180 Hubs: Reserve’s carbon construction provides a tubeless-ready, asymmetric-depth wheelset — shallower up front for crosswind stability, deeper in the rear for aerodynamic efficiency. DT Swiss 180 hubs are among the lightest and most serviceable hubs available in production cycling, with engagement precision that holds up over tens of thousands of kilometers.
5. WorldTour-Proven Geometry: The R5’s handling geometry is consistent with what Cervélo’s WorldTour teams race on mountain stages. Fixed 410mm chainstays across all sizes ensure predictable handling whether you’re on a 48 or a 61. The geometry alignment with the S5 means riders who train on one and race on the other face no adaptation period.

Final Take

The Cervelo R5 Red XPLR AXS 1 E1 is a complete, race-ready climbing machine with no obvious areas left to upgrade. The frame is best-in-class light, the groupset is best-in-class capable, the wheels are excellent, and the cockpit is dialed from the factory across 15 fit combinations. At $14,400, this is a significant investment — and a direct answer to the question of what the fastest climbing road bike you can buy actually looks like.