SHIMANO Shimano Crank Chainset Ult 6600 52/39 172.5mm

The new Ultegra Hollowtech II chainset uses the same two-piece design to maximize its stiffness for the optimum power transfer and minimal weight. A hollow cro-moly spindle is press-fitted into the driveside of the Hollowtech II crankarm, this spindle is what rotates in the new external cups, with little or no flex or loss of power. The bottom bracket bearings are now located outside of the bottom bracket shell to accomodate the oversized axle. The bearings are wider apart in comparison to the 9-speed's, this provides more axle support, yet again improving the power transfer. Amazingly though the Q-factor of the new crankset is unchanged from the 9-speed version. While the cranks themselves look substantially sturdier, when you combine the total weight of chainset and bottom bracket, it saves weight in comparison to its 9-speed predecessor. The Ultegra product range has been designed to be more durable than its lightweight counterpart making it more appealing to a wide range of riders who require performance and durability for years to come. Available in 165, 170, 172.5, 175mm crank lengths and 53/39 or 52/39 ring combo's.