Pro Bike: Carlos Sastre's Cervelo TestTeam Cervelo R5
By James Huang, technical editor | Tuesday, July 20, 2010 7.00am
Most of the Cervelo TestTeam are using the company's aero S3 model but team leader Carlos Sastre has decided on the latest R5 instead James Huang
While his team-mates have long since jumped on the aero road bandwagon with the slippery SLC-SL and now S3, Cervélo TestTeam captain Carlos Sastre has instead preferred to stay on his lighter and more comfortable R3-SL.
It's a logical choice, seeing as how he's a climbing specialist and generally protected from the wind most of the time, anyway. This year's Tour de France, however, sees him on Cervélo's latest incarnation: the R5 (formerly known as Project California).
The R5 builds on the R3's proven Squoval-profile tubes, big chainstays and tiny seatstays, but it's as if Cervélo turned the volume up a few notches. Coming well down the scale, though, is the mass, with a claimed weight under 700g for a 56cm R5. Key changes including a newly tapered front end and new BBright bottom bracket standard.
Cervélo TestTeam race engineer Damon Rinard says that in-house testing revealed definite advantages with a tapered front end but that the commonly accepted 1-1/8 to 1-1/2in standard was actually too rigid. "If you go too oversized at the bottom of the fork you gain so much rigidity that the fork as a whole doesn't absorb energy so it has to be built too strong, making it too heavy and too stiff," he says.
Cervélo engineer Richard Matthews developed a new 1-3/8in lower headset for the R5
Cervélo ultimately settled on a 'sweet spot' of 1-3/8in, using a new lower headset standard that company engineer Richard Matthews developed with Cane Creek (Specialized use a 1-3/8in lower bearing on their Roubaix line but it's a proprietary setup). The matching all-carbon fork is still light but noticeably stiffer and more precise handling than the R3's, according to Rinard. The lower bearing seat is moulded directly into the fork crown, thus eliminating a redundant part and lending a straighter path for the carbon fibres in that area.
The BBright concept is even more interesting. Rinard says the company have long seen advantages with the BB30 system, with its stiffer and lighter 30mm diameter, but never understood why there was so much unsupported spindle on the non-drive side. BBright adheres to the standard on the drive side but pushes the non-drive side bearing out by 11mm, filling in the dead space and providing better axle support, but without affecting pedal stance width.
The BBright bottom bracket's PressFit-30 cups are just visible inboard of the crankarms
Rinard says it's fairly easy for crank manufacturers to adapt existing BB30 crank designs to BBright as only the spindles need to be modified and standard BB30 bearings can be used (the R5 uses PressFit 30 cups). Combining the bigger head tube and BBright shell left Cervélo with a lot more real estate to play with and they look to have used it well.
The asymmetrical down tube is bigger up front and now extra-wide down below, the seat tube is similarly offset and broadened, and the non-drive side chainstay has nearly doubled in breadth. While the drive side stay is still offset at the dropout to clear the cogs and chain, the non-drive side stay comes in straight on for better structural efficiency.
Cervélo take advantage of the BBright standard's dimensions by widening the down tube
Other details include new carbon fibre dropouts, low-friction external cable routing with moulded-in carbon housing stops, a carbon fibre seatpost clamp with titanium and aluminium hardware and a keyed shape to keep it from rotating on the frame (the seat clamp and three seat tube slots are offset from each other for more even clamping force), and a slightly altered frame geometry. Rinard wouldn't fully elaborate on the geometry changes but did confirm a slightly longer head tube on some – but not all – sizes. His comments to us suggest more stable high-speed handling, too.
As for the extra room given by the new bottom bracket, Rinard says: "We haven't finalised just how much of that bonus we want to keep as a stiffness increase and how much we want to cash in as further weight decreases." Comfort looks to be well retained, as the seatstays are slightly slimmer than the ones on the R3 and the chainstays, though taller up at the bottom bracket, now taper far more aggressively in height.
Chainstays are taller at the bottom bracket than before but taper down more dramatically
Team mechanics build up Sastre's bike with a mix of bits from sponsors SRAM, Zipp, 3T, Rotor, Fizik, Speedplay, Vittoria and CycleOps. Standout items include SRAM's special Red LTE group with yellow highlights, Zipp 404 carbon tubular wheels, a yellow-accented 3T carbon seatpost, bar and stem, and Rotor's revised elliptical Q-Rings with new tooth profiling for smoother downshifts.
Rotor's new 3D crank is worth some extra attention as it's not only compatible with the R5's BBright system but also standard BB30, PressFit-30 and even threaded 68mm-wide shells with a special bottom bracket. Details are limited pending the crank's official release at this autumn's Eurobike trade show but it's a fair assumption to expect a longer machined section on the spindle to accept multiple bearing positions and a bit of extra length on the drive side to accommodate an externally located cup.
Rotor have developed new Q-Rings for the team with updated tooth patterns and graphics
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With all of these lightweight parts bolted to what is one of the lightest frames out there, one can't help but wonder how the sum total meets the UCI-mandated minimum weight of 6.8kg – and that'd be a fair question since it doesn't, at least not without a little help. "To stay legal, TestTeam mechanics add as much useful weight as Carlos can stand in component selection, then slip a solid steel bar into the seat tube to top it off," Rinard told us.
"Carlos insists we put it over, not at, the limit so there's no chance it could be measured under." By that account, we'd guess Sastre's bike is around 6.9kg (15.2lb) or so but when the R5 ultimately becomes available to the public, deep-pocketed consumers will undoubtedly be able to build it up much, much lighter.
Complete bike specifications
Frame: Cervélo R5
Fork: Cervélo R5
Headset: Cane Creek
Stem: 3T ARX-Pro special edition, 120mm x -17°
Handlebar: 3T Rotundo Pro special edition, 42cm (c-c)
Front brake: SRAM Red LTE w/ SwissStop Yellow King pads
Rear brake: SRAM Red LTE w/ SwissStop Yellow King pads
Brake levers: SRAM Red LTE DoubleTap
Front derailleur: SRAM Red w/ steel cage
Rear derailleur: SRAM Red LTE
Shift levers: SRAM Red LTE DoubleTap
Cassette: SRAM Red
Chain: SRAM PC-1091R
Crankset: Rotor 3D-BBright, 170mm, w/ 53/38 Rotor Q-Rings
Bottom bracket: SRAM PressFit-30
Pedals: Speedplay Zero Titanium
Wheelset: Zipp 404 tubular
Front tyre: Vittoria Corsa EVO-CX tubular, 23mm
Rear tyre: Vittoria Corsa EVO-CX tubular, 23mm
Saddle: Fizik Aliante w/braided carbon rails
Seatpost: 3T Dorico LTD special edition
Bottle cages: Elite Custom Carbon (x1)
Computer: CycleOps Joule 2.0
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