Why the new Cervélo S5 adds to the fork and ditches the front derailleur (on one model)

I’ll get to the aerodynamics of the new Cervélo S5 in just a moment (and my ride impressions at the end). Slipping through the wind has always been at the S5’s core. You’ve no doubt seen this new model, this terribly kept secret, at the Critérium du Dauphiné and now at the Tour de France. It has new features that serve riders such as Jonas Vingegaard. But first, a detour through the drivetrain and race won by Vingegaard’s former teammate more than two years ago.

The drivetrain of the Cervélo S5

You’ll recall the uphill time trial that decided the 2023 Giro d’Italia. Primož Roglič used a SRAM 1-by setup with a gravel-oriented SRAM XPLR cassette. He also used it on the previous stage up Tre Cime di Lavaredo. The team made the decision to run this gearing as it tried to eke out weight savings and aero gains. While the innovation came from out in the field, the squad of Jumbo-Visma (today Team Visma-Lease a Bike) has sympathetic people over at its bike supplier. Terry Best, Cervélo product manager, has been a long-time advocate for 1-by on the road. He points out that a bike gets lighter when you ditch a front derailleur. Also, he cites performance advantages that the rider gets as a 1-by setup encourages them to work on cadence and build their abilities to turn bigger gears. The team’s successes with 1-by bolster Best’s championing of the system.

(On the topic of Roglič’s dropped chain during the final Giro TT, Best pointed out that the chain went off the cassette because the limit screw wasn’t set properly. The mechanical was a setup error, not the fault of the 1-by system.)

The flagship build for the latest Cervélo S5 is 1-by, featuring a 10-46 tooth SRAM Red XPLR cassette and an aero 50-tooth SRAM Red 1 E1 chainring. There are 2-by builds with Shimano and SRAM groups, but if you want the most out of the S5, Cervélo is going to point you in the direction of a single chainring. According to the company’s calculations, the 1-by spec gives you the same high gear inches as SRAM Red or Force with 50/37 rings and 10-33 cassette and a lower low gear. The S5’s configuration has a higher high and lower low gear than what’s available through the 54/40 chainrings with 11-34 cassette of a Shimano Dura-Ace groupset.