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Cervélo unveils new S5 aero road bike

By:
James Huang
Published:
June 29, 2011, 14:33 BST,
Updated:
June 29, 2011, 15:32 BST
Edition:
Second Edition Cycling News, Wednesday, June 29, 2011
Race:
Tour de France
Cervelo has launched a new S5 aero road bike whose P4-inspired shape is said to save nearly 40 seconds over a 40km course at 40km/h relative to the already slippery S3.

Cervelo has launched a new S5 aero road bike whose P4-inspired shape is said to save nearly 40 seconds over a 40km course at 40km/h relative to the already slippery S3.

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Claimed to save 37sec over 40km compared to S3

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 claims will save riders nearly 37 seconds over a 40km course (at 40km/h) relative to its already slippery S3. Naturally, that 92 grams of drag reduction (or over nine watts 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, though, but the chain stays are similarly huge nonetheless. According to Cervélo, the aero seat stays are set a little more broadly up top to help direct air around the caliper.

Aero downtube with an allowance for a bottle cage.

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 has notably flattened the trailing edge of the down tube down by the water bottle mount, though, saying the less abrupt transition is better able to maintain good aerodynamic performance when a bottle is actually mounted. Moreover, Cervélo has 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..

Interestingly, Cervélo has 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 suitably rigid. Down below is Cervélo's BBright extra-wide, asymmetric, and oversized bottom bracket shell similar to what is found on the latest R3 and R5. Of course, 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 is nevertheless 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 rigidity (along with a similar increase in ride stiffness, though). 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).

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 -73° 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 that have to have the latest and greatest will be able to bring one home beginning July 1. 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

This article originally appeared on BikeRadar.

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