The new four-arm chainring bolt circle is not radially symmetric. Instead, Shimano says the arms are aligned more with how forces are transmitted during the pedal stroke, adding more material where it's needed and removing it where it isn't. Replacement chainrings will almost assuredly be very expensive.
In this exclusive video, BikeRadar gets a first look at the latest electronic groupset soon-to-be released from Shimano. The Dura-Ace Di2 11-speed ensemble was being fitted to Fabian Cancellara's RadioShack-Nissan Trek Domane.
A number of new features are discussed including the additional port made available at the Di2 lever for combined use of the ‘sprinter' shifter and the bar-mounted shifter often used for cobbled races. Shifting has undergone some additional changes which allow further adjustments.
The RadioShack-Nissan team was just one of five WorldTour squads who were fitted with the newest groupset with Cancellara taking part in pre-production testing program that begun just before the Vuelta a España. The groupset being fitted to the bike was the first production model.