SHIMANO’S NEW XTR Di2 is a step up from the electronically controlled transmissions that until now have been the preserve of our roadie cousins. Uprated mech motors allow muddy shifts, while riders can choose to shift manually or select one of two user-defined ‘SynchroShift’ modes, where the front mech moves automatically to give race-car-like sequential shifting.
The shifters have a tactile feel, with a defined ‘click’ as you shift. You can adjust the lever reach, and the paddles are shaped and textured to prevent thumb slips. Some testers did struggle to find a comfortable position for the shifters next to their brake levers though. Needing only one shifter in SyncroShift mode is XTR Di2’s winning ticket, clearing space for an under-bar dropper post lever and reducing cable faff. It does feel like Shimano have missed a trick though, attempting to mimic a mechanical feel when a smaller, less intrusive button approach could have worked.
Unlike SRAM’s 11-speed cassettes, the 11-40t XTR block can be mounted to a standard freehub body. Jumps between gear ratios are kept below 15 per cent – ideal for racers who watch their cadence carefully – and shifting is ridiculously accurate, with no noise or misshifts during testing. In muddy conditions, the clutch-controlled mech powers through regardless, and without gear cables, feel at the shifter remains neutral, though not as solid as with SRAM. Up front, the powerful mech motor means shifting remains accurate even under power. Our crank arms suffered shoe rub within just a couple of rides though.
The bar-mounted display is easy to read and shows your gear selection, battery life and SynchroShift mode. It sits next to the stem, but we’d like to be able to mount it over the stem for a cleaner look. Plug the system into aWindows PC and Shimano’s simple to use E-Tube software lets you adjust the lever functions, shifting speed and SyncroShift ratios. You can also integrate it with Fox’s iCTD suspension control system. Don’t be put off by all the electronics though, because XTR Di2 is incredibly intuitive to use. The shifter feel never changes, regardless of the conditions, giving a sense of infallible performance. There’s little doubt that it represents the pinnacle of shifting performance, but until the technology trickles down, its price is eye-wateringly high. The system also makes a lot more sense on Di2 ready frames.
Reliable, accurate, smart shifting from Shimano, though shifter ergonomics could be improved
PRICE 2640$
