Cervélo released information today on a new S5 flagship aero road machine set to debut at the start of the Tour de France that the company claim will save riders nearly 37 seconds over a 40km course (at 40km/h) relative to their already slippery S3.
Naturally, that 92g of drag reduction (or over 9w of power output) comes with some radical tube shaping and there’s more than a little bit of influence taken from the time trial/triathlon-specific P4 model.
That design language is most evident in the rear end, which includes a kinked seat tube with a deep-section profile, close-fitting rear wheel cutout, and nearly upright aero-section telescoping carbon seatpost. The S5 will use a conventional rear brake instead of the P4’s integrated calipers, but the chainstays are huge nonetheless. According to Cervélo, the aero seatstays are set a little more broadly up top to help direct air around the caliper.
The down tube uses an airfoil profile through the upper section but the trailing edge is squared off for smoother airflow around bottles. according to cervelo, riders running just a single bottle can save an additional 15g of drag just by using the lower set of mounts.: the down tube uses an airfoil profile through the upper section but the trailing edge is squared off for smoother airflow around bottles. according to cervelo, riders running just a single bottle can save an additional 15g of drag just by using the lower set of mounts.Cervelo
Aero downtube with an allowance for a bottle cage
Again like on the P4, the new S5 boasts a dropped aero-section down tube that supposedly makes for smoother airflow off of the front wheel and flush-fit fork crown. Cervélo have flattened the trailing edge of the down tube down by the water bottle mount, saying the less abrupt transition is better able to maintain good aerodynamic performance when a bottle is mounted. Moreover, Cervélo have provided two bottle mounts: one in a standard location and another one set extra-low, with the latter position supposedly generating 15g less drag.
Cervelo sticks with a conventional 1 1/8in steerer to decrease frontal area.: cervelo sticks with a conventional 1 1/8in steerer to decrease frontal area.Cervelo
Cervélo have opted to stick with a straight 1-1/8in head tube for a narrower hourglass-shaped frontal profile though it, too, uses a very deep teardrop shape that should help keep the front end rigid. Down below is Cervélo’s BBright extra-wide, asymmetric and oversized bottom bracket shell, similar to that found on the latest R3 and R5. Routing is fully internal, with the derailleur housings fed into the top of the top tube as on the S3.
Despite the improvement in aerodynamics, Cervélo are claiming that the S5 is an improvement over the S3 in other performance metrics, too, to the tune of 990g for a painted frame, 340g for an uncut fork, and a 12 percent jump in drivetrain and torsional stiffness. According to Cervélo PR man Mark Riedy, the included fork is also stouter laterally than the 3T Funda model used on the S3 (or Specialized’s new Venge, for that matter) but overall ride quality is supposedly unaffected.
While the look and aerodynamic features of the new S5 are borrowed from the P4, the geometry is instead taken from Cervélo’s current R3. In other words, prospective buyers can expect taller head tubes than in years past (though still short enough to achieve Garmin-Cervélo team-spec bar heights with -17° stems) and proportional head tube angles for more consistent handling across the size range. Buyers looking for an aero machine that can serve double duty as a light time trial or triathlon rig will also take interest in the two-position seatpost head.
We’ll have to wait until Friday morning for a possible first test ride but Cervélo fans who have to have the latest and greatest will be able to bring one home beginning 1 July. Prices for various complete S5 bikes are as follows:
S5 with Shimano Dura-Ace Di2: US$9,000
S5 with SRAM Red: $7,500
S5 with Shimano Ultegra Di2: $6,000
S5 with Shimano Ultegra 6700: $4,800
S5 with SRAM Rival: $3,800
UK prices are for frameset only, with availability from November 2011: