• Science for cyclists

    Science for cyclists
    Date:30 June 2009 Tags:

    Professional bike race teams turn high-tech to mod their rides for the Tour de France.

    The design and materials of Tour de France bicycles have more in common with aircraft than the BMX a kid rides to the park. "We optimise every single aspect of the bike," says Jim Felt, founder of Felt Bicycles, which outfits professional cyclists around the world. Rider David Zabriskie (right) works with Felt and his team, Garmin-Slipstream, to keep his 7,2 kg bike studded with innovations.
    "A lot of guys don't like changing," Zabriskie says. "But for me, getting the new stuff makes me believe I'm going to go a lot faster." It's hard to argue with the results: Zabriskie holds the record for the quickest time trial in the history of the Tour de France, averaging 54,5 km/h over 19 km. Time trials are staggered throughout the Tour. Riders who do well shave valuable seconds from their current times.

    Gears
    Gear manufacturers are incorporating high-tech materials such as carbon fibre and exotic alloys in their gear sets to make them lighter. Zabriskie’s Shimano gears are made from titanium.

    Handlebars
    Zabriskie’s timetrial bike (above) doesn’t yet have new electronic shifting, but his road bike soon will. A buttonactivated solenoid triggers the derailleur to shift gears. Multiple shiftingbuttons can be placed anywhere on the handlebars.

    Frame
    New ways to layer carbon fibre give riders stiffer bikes, which allows more of the rider’s energyto be transferred to the wheels. The team uses software to tweak frame designs before costly testing in a wind tunnel starts.

    Water bottle
    New aerodynamic water bottles make the bike faster by acting as fairings that reduce drag on the back wheel. In addition, new bike frames feature a seat tube with a cutout to further smooth airflow.

    Rear brakes
    Pro bike manufacturers mount rear brakes down towards the bottom bracket to de-clutter the frame. Front brakes are being moved inside or behind the bike’s front fork.

    Wheels
    This solid-core rear wheel, built by Zipp Speed Weaponry, is parabolic to improve airflow. The surface of the carbon-laminate rim on the rear wheel is dimpled. As with a golf ball, the dimples help to cut through the wind and decrease drag.
     

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