The Cervélo S5, by a clear margin. Cycling News's independent wind-tunnel test measured the S5 saving 27.57 W at 40 km/h versus their baseline bike — they called it the fastest bike they've ever tested. Cervélo's own claim is 6.3 W faster than the previous S5, with Reserve 57|64 wheels alone contributing 3 W of that gain.

3T hasn't published comparable wind-tunnel numbers for the Strada, but reviewers consistently describe the S5 as the more aerodynamically optimized of the two — particularly at race speeds above 35 km/h.

Neither is a pure climber, but the Cervélo S5 has the weight edge. The new S5 dropped 124 g from the previous generation, with size-56 builds landing in the 7.17–7.44 kg range. The 3T Strada typically weighs 7.8–8.3 kg in equivalent trim — heavier in part because of its wider stock tires and deeper-section stock wheels.

That said, both bikes are described as 'sluggish' on steep gradients compared to dedicated lightweight climbers like the Specialized Aethos or Cervélo R5. If your riding is mostly mountainous, neither is the right tool.

3T Strada: 35 mm officially — the widest in the aero-road class. Reviewers regularly run 32 mm Continental GP 5000 S TR or Vittoria Corsa Pro tires that measure ~34 mm on the wide stock rims.

Cervélo S5: 34 mm officially, ships with 29 mm Vittoria Corsa Pro TLR. One reviewer was skeptical the 34 mm claim is realistic and felt 32 mm was already a tight fit. For anything you'd genuinely call gravel, the Strada has more headroom.

The 3T Strada uses a 72.5° seat tube angle across all sizes — about half a degree slacker than a typical race bike. 3T's design intent is to weight-balance the rider for sustained aero positions on long days. The tradeoff: riders who prefer a forward, race-style hip position over the bottom bracket often have to slam the saddle as far forward as possible, sometimes with a zero-offset post, to find the position they want.

The S5 stays at a more conventional 73° seat tube on the 54, which most riders will find feels normal out of the box.

Less than you might think. Cervélo's HB19 is a one-piece carbon bar/stem unit, so changing width or length means buying a new bar. To soften that, Cervélo offers a 60-day post-purchase swap at no additional cost if your initial choice doesn't fit. The new S5 also drops the cut-to-fit steerer, simplifying height adjustments.

The 3T Strada uses a two-piece cockpit instead — the 3T More stem with hoses routed under the stem rather than through it, which makes stem swaps and bar-roll adjustments meaningfully easier than on most modern aero bikes.

Yes, both. The S5 Red XPLR AXS 1 is the flagship build and runs SRAM's 13-speed XPLR system with a 10–46T cassette — Cervélo positions 1x as the top aero-optimized spec. The 3T Strada ships exclusively as 2x at the moment (Ultegra Di2 or 105 Di2), but the frame uses a SRAM UDH dropout and 3T has built around future 1x convertibility.

One caveat from reviewers: the S5's 13-speed 1x can feel like it's hunting for a 'Goldilocks gear' on long, steady climbs.

The 3T Strada is genuinely engineered for it — the curved seat tube acts as a leaf spring for vertical compliance, and the 35 mm tire clearance lets you run wider rubber at lower pressures. Reviewers consistently call out comfort-on-rough-roads as its standout trait.

The S5 is comfortable for an aero race bike — wider Reserve rims and 29 mm stock tires take the edge off — but the underlying ride is firm. Expect to feel the road on long days. Multiple reviewers noted the S5 is rideable for centuries but isn't where the bike 'shines.'

3T Strada: Two years on frame and 3T components, extended to five years if registered with 3T within 30 days of purchase, plus one year on paint.

Cervélo S5: Lifetime frame warranty to the original owner against manufacturing defects, with crash-replacement pricing typically available.