Shimano Ultegra Di2 RD-R8150 Rear Derailleur - 12-speedUltegra R8100 Leave Time Behind When developing the Ultegra R8100 series, Shimano took a holistic and 100 % performance oriented approach, because great speed means great responsibility. Faster than ever before, the 12 speed road groupset scores with unparalleled control and comfort anytime and anywhere whether in an everyman race, on the hunt for a personal best time or on a companionable ride. As with the Dura Ace R9200, not only does Hyperglide+

Upgraded penetration power

L3: 250 mm: IEWJC130SS

BR-R785 & Alfine BR-S700 calipers

front difference      : 20T

the index is spot on as well

The coating not only protects the printed graphics but also enhances abrasion and oil resistance

the R7000 rear derailleur is compatible with 11-speed road drivetrains and is offered in silver and black

Q-Factor: 151mm

SIZE:  29X2

With an integrated chain stabilizer mechanism

Group: Tiagra

42T (2x11/2x10-speed)