fonte:http://velonews.competitor.com/2013/04/news/under-pressure-tire-tech-from-paris-roubaix-2013_281135/attachment/tires-of-roubaix
Tire tech from Paris-Roubaix 2013
ROUBAIX, France (VN) — There is a sphere of physical force within which most cycling gear is designed to excel. Paris-Roubaix is nowhere near it.
The equipment used on this single Sunday in April is special, so much so that it is rarely touched for the hundreds of other racing days on the calendar. There is no race on the planet that is tougher on equipment than Paris-Roubaix.
Wheels and tires bear the brunt of the brutish day, and receive special attention as a result. Riders and mechanics spend days on the cobbles, fine-tuning product choice and tire pressure.
The conclusions they draw, though, are somewhat varied. Pressures range from the low 60psi to nearly 90. Tire widths can be as narrow as 24-25mm and as wide as 30mm. Rim types span from box section to 50mm aerodynamic shapes and nearly everything in between.
Under pressure
Tire pressure receives more attention than any other variable, becoming something of a technology in and of itself. Many teams refused to share specific pressure figures, stating bluntly that they didn’t feel the need to let other teams in on the fruits of their research.Team Sky even went as far as to test the effects of filling its FMB Paris-Roubaix tubulars with nitrogen rather than regular air (which is 78 percent nitrogen anyway). The goal is to solve a problem that has plagued racers for decades: preventing the slow drop in tire pressure that occurs with the high-end, hand-built, latex-tubed tubulars used at Roubaix.
Nitrogen molecules migrate through rubber more slowly, theoretically slowing the decrease in tire pressure teams see throughout the race. But filling a tire with 100 percent nitrogen is a time-consuming process, and Sky decided to skip the hassle come race day.
“We tried it. These tubulars lose a lot of air; they lose up to a bar (15psi) over the course of a race,” said Sky mechanic Gary Blem. “That’s a lot. We tested to see if filling the tires with nitrogen would slow that down. We didn’t see much change. Or anything, really. Not enough to make it worth the effort.
“But we will keep looking into it. The way we inflate them could change, and maybe make it more effective.”
In the end, Sky ended up running regular old air, and would not provide specific pressure figures. Blem said only that all his tires were “under 5.5 bar,” or about 80psi.
“We didn’t have a single puncture last year,” he said. “So we know what they can handle, and we know how low they can go.”
Tire choice
Just as they did at the Tour of Flanders, most teams ignored sponsor obligations at Roubaix. Continental and Vittoria were relatively successful at keeping its squads sponsor-correct, but only because both make an adequate pavé tire — the 27mm Competition and 27mm Pavé, respectively.Once again, the two French handbuilt brands, FMB and Dugast, stole the day. Cancellara swapped out the FMB 25mm tires he used at Flanders for a 27mm set, giving the small company its second win in as many weeks.
Cancellara inflated his FMBs to a relatively high 81psi (front) and 88psi (rear).
“He tends to run high pressure, on and off the cobbles,” said Trek team liaison Jordan Roessingh.
Dugast was found throughout a number of French squads, among them Europcar, FDJ, and Cofidis, but never covered every wheel. The Dugast Roubaix tires feature a tall, sharp tread that is generally preferred for those editions of Roubaix that see a bit more precipitation; this year, the course was in good condition. Relatively speaking, of course.
A few riders went with the massive 30mm Dugasts anyway, likely just for the extra cushion they provide, paved sections be damned.
Runner-up Sep Vanmarcke and the rest of his Blanco squad were on unlabeled, but certainly handmade, 27mm tubulars. The tread pattern appears to be off a Veloflex Roubaix, but the casing doesn’t match their current offerings; it’s entirely possible that the black casing was a special run, of course.
Team equipment selection
Few teams would provide precise tire pressures. Listed pressures are a “team average” provided by a mechanic, except where otherwise noted.Team Sky
Wheels: Shimano Dura-Ace C50
Tires: FMB Paris Roubaix 27
Tire size: 27mm (28mm actual size)
Pressure: Precise numbers are secret, “every tire is under 5.5bar (80 psi)”
FDJ
FMB Paris Roubaix 27
Wheels: Shimano Dura-Ace C35
Tires: Unlabeled. Appear to be Dugast
Tire size: 27 and 30mm
Pressure: 70 front, 80 rear
Saxo Bank-Tinkoff Bank
Wheels: Zipp 303 Firecrest
Tires: FMB Paris Roubaix (rebadged as Specialized)
Tire size: 27mm
Pressure: secret
AG2R
Wheels: Fulcrum Racing Speed XLR
Tires: FMB Paris Roubaix
Tire size: 27
Pressure: 63 front, 75 rear
RadioShack-Leopard
Wheels: Bontrager Aeolus 5 D3
Tires: FMB Paris Roubaix
Tire size: 27mm
Pressure: Cancellara used 5.6bar (81psi) front and 6.1bar (88bar) rear
Omega Pharma-Quick Step
Wheels: Zipp 303 Firecrest
Tires: Specialized labeled, appear to be FMB Paris Roubaix
Tire size: 27
Pressure: Terpstra had less than 60psi front and under 65 rear
Katusha
Wheels: Mavic Cosmic Carbone and M40
Tires: Unlabeled, appear to be FMB Paris Roubaix
Tire size: 27mm
Pressure: Less than 6 bar (87psi)
Cannondale
Wheels: Vision Metron 40
Tires: Unlabeled, appear to be FMB Paris Roubaix
Tire size: 27mm
Pressure: secret
Astana
Wheels: Corima Viva S, custom built with stronger rims
Tires: FMB Paris-Roubaix
Tire size: 27mm
Pressure: secret
Vacansoleil-DCM
Wheels: FFWD F2R and F4R
Tires: Veloflex Ardennes
Tire size: 27mm
Pressure: secret
Endura NetApp
Wheels: Oval
Tires: Vittoria Pave 2
Tire size: 27mm
Pressure: 81psi front, 87 rear
Bretagne-Seche Environnement
Wheels: Miche
Tires: Michelin Pro4 Service Course
Tire size: 25mm
Pressure: 75 front, 82 rear
Movistar
Wheels: Campagnolo Hyperon
Tires: Vittoria Pave
Tire size: 27
Pressure:
Euskaltel-Euskadi
Wheels: Shimano Dura-Ace C35
Tires: Vittoria Pave
Tire size: 27
Pressure: “less than 6 bar (87psi)”
Europcar
Wheels: Campagnolo Bora Ultra
Tires: Unlabeled, appear to be mixed Dugast and FMB
Tire size: 27-30mm
Pressure: “variable”
Argos-Shimano
Wheels: Shimano Dura-Ace C35 and C50
Tires: Unlabeled, appear to be Veloflex Roubaix
Tire size: 27mm
Pressure: John Degenkolb ran 5 bar (72psi) front and 5.3 bar (76psi) rear
Orica-GreenEdge
Wheels: Shimano Dura-Ace C35
Tires: Continental Competition
Tire size: 27mm
Pressure: 72 to 87psi, depending on rider
BMC
Wheels: Shimano Dura-Ace C35 and C50
Tires: Continental Competition
Tire size: 27
Pressure: Under 6bar (87psi)
Lampre-Merida
Wheels: Fulcrum Racing Light XLR, with some riders in aluminum Ambrosio Nemesis rims
Tires: Continental Competition ProLtd
Tire size: 28mm
Pressure: around 6bar (87psi)
Lotto-Belisol
Wheels: Campagnolo Hyperon
Tires: Continental Competition
Tire size: 27
Pressure: secret
Blanco
Wheels: Shimano Dura-Ace C50
Tires: Unlabeled, appear to be Veloflex Ardennes
Tire size: 27mm
Pressure: Under 72psi front, under 80psi rear
Cofidis
Wheels: Mavic Cosmic Carbone
Tires: Unlabeled, mostly FMB Paris Roubaix, some Dugast
Tire size: 27mm, some 30mm
Pressure: 70-80 psi, depending in rider
Garmin-Sharp
Wheels: Mavic Cosmic Carbone and M40
Tires: FMB Paris Roubaix
Tire size: 27
Pressure: 5-6 bar (72-87psi)
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