Tour tech 2012: Rotor launch new aero chainset

Rotor have launched a new aerodynamic chainset called the Flow and it has already made an appearance in the Tour de France. The Team Garmin Sharp riders have the Flow fitted to their Cervélo P5 time trial bikes.

The Spanish brand reports that the aero shape was developed in a partnership between their own engineers and Robby Ketchell, Director of Sport Science at Garmin Sharp.

The shape of the crank arms was designed by Ketchell using CFD (computational fluid dynamics) software to simulate a wind tunnel, and they reckon that the new crank is 10% stiffer and lighter than most other aero cranks on the market.

To put a figure on the weight, Rotor are claiming just 562g for a 175mm version without chainrings. And they say that an athlete averaging 200 watts over 180km/112.5 mile (the length of the bike leg of an Ironman triathlon) will save 26.4secs over a standard chainset. That’s not a vast amount of time over several hours, clearly, but if you’re after marginal gains, it all counts.

The chainset comes with what Rotor call a Micro Adjust Spider to ensure the perfect setup if you use their non-round chainrings. You get more positions on the Q-Rings to get the orientation compared to the crank arms exactly how you want it. The Q-Rings alone offer five different positions and combined with the Micro Adjust Spider you get another five.

You don't have to use the Flow chainset with Rotor's own Q-Rings - you can go with standard rings if you like. About half of the Garmin Sharp riders use Q-Rings.

The Flow chainset should be available from September although we don’t have a UK price yet.