The Shimano 105 R7150 Di2 groupset is perhapswithout exaggerationthe most hotly anticipated groupset of the century. Even in mechanical form, the 105 series is widely regarded as one of the most reliable and affordable performance groupsets, with the introduction of electronic the gap between the brands mid-tier range and its top-tier is now closer than ever.

A Battery For The Ages: The introduction of wireless shifting might leave you feeling concerned youll be forever charging batteries and living in perpetual fear youll be stranded in you biggest gear miles from anywhere. But with 105 Di2, power is supplied via two CR1632 coin cell batteries in the shifters, which should provide over three years of life. With such a range, even the heaviest of users shouldnt find themselves in a constant state of charging and re-charging batteries.

Semi-wireless Setup: 105 R7150 uses the same semi-wireless, 12-speed shifting setup as the top-tier models. The proprietary semi-wireless system means there is no longer any need from wires to the shifters to the derailleurs. Since theres no need for wires and cables, the cockpit of a bike set up with 105 Di2 is cleaner and less cluttered than ever.

Shift Into Gear: Of course with the change to electronic gearing, one of the most significant changes to the groupset is in the shifters themselves; the all-new 105 ST-R7170 levers now operate in much the same way as the top-of-the-line shifters. Shifting gear couldnt be simpler: click a button on the shifter and almost instantly youll hear the derailleur whir into life. Drawing on Shimanos years of experience in electronic shifting, you can expect smooth gear changes at the touch of a button.

Without the need to accommodate levers, wires, or ports, the shape of the R7150s levers has been brought more in line with the sleeker Ultegra and Dura-Ace shifters. The new, slimmed down, STI levers are also more ergonomically shaped, thanks to the raised hood peak and offer more opportunity to refine the reach.

The Brains Of The Operation: Another significant change to previous mechanical setup is in the front and rear derailleurs. The rear derailleur is an integrated, 12-speed wireless unit, which will comfortably accommodate an 1136T cassette. Such a wide range of gears is perfect for those big climbing days, without spinning out when the road tips back down or when youre racing along in fast bunch rides. The rear mech uses Shimanos Shadow technology is incorporated to reduce the risk of the derailleur hitting the chainstay in rough-riding conditions, and to provide smoother, quieter performance.

The 105 Di2 front derailleur offers the smooth shifting youd expect from the Japanese component makers. It can be programmed to be manual, or full or semi-synchronised, accommodating a 50T or 52T chainring.

Crank It Up: Shimano continue to deploy their famed Hollowtech II technology in the R7100 crankset, which is now 2×12-speed. This is the same technology they have employed in the 105 range for years, and features also in the companys premium lines. The result is a sturdy crankset, that is stiff and relatively light. Incorporated also is Hollowglide technology, which offers more precise and efficient power transfer than ever before. Shimano have been able to reduce the weight of the crankset but maintain stiffness, strength, and performance.

For 105 Di2, cranksets are available as a compact (50-34 tooth) and in crank-arm lengths of 170, 172.5 and 175mm

Stopping Performance: The 105 hydraulic disc brakes of the previous iteration were highly capable; for the latest ST-R7170, Shimano have further improved braking performance. The lever-action required for braking is now lighter and smoother, offering a greater area for braking control. For 105 Di2, the clearance for pads has been increased by 10%, reducing braking noise. Overall, rain or shine, you can be assured of high-performance stopping power.

Included:

• Left and Right Shifters (ST-R7170)
• Flat Mount Brake Calipers (BR-R7170)
• Chainset (FC-R7100) (50-34T)
• Cassette (CS-R7100-12) (11, 12, 13, 14, 15, 17, 19, 21, 24, 27, 30, 34T)
• Front Derailleur (FD-R7150)
• Rear Derailleur (RD-R7150)
• Rotors (SM-RT70)
• Di2 Battery (BT-DN300)