One-by Shimano drivetrain with XTR Di2 rear derailleur spotted on Joshua Tarling's Pinarello Dogma F ahead of Paris-Roubaix

Joshua Tarling’s Pinarello Dogma, ridden at the upcoming Paris-Roubaix, has been spotted equipped with a one-by Shimano drivetrain featuring the XTR Di2 M9250 rear derailleur. This wireless rear mech, notable for its internal battery housed within the parallelogram, eliminates the need for wiring and reduces the risk of mechanical failure or snagging on the cobbles. The setup is seen on several Ineos Grenadiers riders’ bikes, signalling a shift towards more robust and simplified electronic shifting systems in the Classics. The XTR Di2 M9250 derailleur is compatible with Shimano’s 12-speed Dura-Ace R9200 shifters and cassettes, allowing for a broad gear range that can extend up to an 11-34T cassette. This flexibility supports larger chainrings, likely in the 56 or 58-tooth range, to meet the demands of the Paris-Roubaix’s rough terrain. Since Shimano does not produce a narrow-wide chainring, teams have turned to aftermarket options such as Drag2Zero, while others, like UAE Team Emirates-XRG, use Carbon-Ti components or opt for traditional two-by chainring setups to enhance shifting reliability. Unlike previous mechanical XTR models, the M9250 uses a double-spring design to improve chain retention by approximately 70%, a crucial feature for the cobbled sections of Paris-Roubaix. This non-adjustable system requires minimal maintenance and promises greater durability in the event of crashes, making it well suited to the rigours of one of cycling’s toughest one-day races. The move towards one-by drivetrains in road racing, popularised by SRAM’s extensive offerings, is gaining traction among Shimano-equipped teams looking for simplicity and reliability. The adoption of this wireless XTR Di2 setup by Ineos Grenadiers represents a notable development in race bike technology, blending mountain bike drivetrain robustness with road racing precision. As the Paris-Roubaix approaches, further insights into gear choices and performance will likely emerge, potentially influencing drivetrain trends in the Classics and beyond. This innovation underscores the ongoing evolution of electronic shifting systems tailored to the specific challenges of elite road racing.