Shimano Ultegra 6770 Di2 Rear Derailleur

Shimano Ultegra RD-6770 Di2 Rear Derailleur

• Fast, precise and smooth electronic shifting – even under load.
• Easy electronic adjustment system.
• Programmed automatic reaction at the touch of a switch makes the RD-6770 Di2 Rear Derailleur quick, smooth and effortless to shift.
• High-strength cold-forged aluminium link plates and body construction ensures lightweight durability.
• Four self-lubricating micro-machined fluorine-coated link pivot bushings guarantee low-friction shifting.
• Crash saver function - the mech is fused to protect the electronics from strong impacts.
• The mech's wide capacity means that it is equally capable of working with compact or traditional racing double chainsets and with cassettes up to 11-28t.
• Linking the derailleurs to the shifters via the Di2 microchip means farewell to chain rub.
• The front derailleur automatically 'trims' itself in tandem with the rear mech's travel as it moves the chain up and down the cassette.
• Di2 guarantees super-fast and precise shifting at the touch of a button.
• Replacing the traditional mechanical cable with an electric cable eliminates poor shifting caused by kinks, corrosion and stretching, and guarantees effortless gear shifts.
• Manufacturer's published weight: 270g.

Shimano Ultegra Di2 Overview

Once there were doubters. Now in its fifth year, after being tested on the muddiest cobble-stoned highways, Shimano Dura-Ace electronic gear shifting is now the standard in road racing. So much so, in the 2011 Tour de France, the yellow, the green and the polka dot jerseys all went to riders on Shimano Dura-Ace Di2-equipped bikes.

Replacing the traditional mechanical cable with an electric cable eliminates poor shifting caused by kinks, corrosion and stretching, and guarantees effortless gear shifts - just as good hydraulic (cable-free) brakes have revolutionised mountain bike braking performance.

Unfortunately, Shimano Dura-Ace Di2 comes at a price. As is the Shimano way, electronic shifting has now trickled down to the more affordable Ultegra level for us 'privateer' riders who don't have sponsorship.

As with Dura-Ace, changing gear with fingertip-actuated Ultegra electronic shift buttons is easier, faster and more accurate than you ever experienced before with 'acoustic shifters'. As Shimano so eloquently put it, 'just a light touch, as soft as a mouse click, is sufficient for the front or rear derailleur to instantaneously select the correct gear'.

With additional benefits such as simple adjustment at the press of a button and automatic 'trim' to prevent front derailleur rub, this inaugural Shimano Ultegra Di2 groupset gives you a glimpse into the future of bicycling.

Technical editor Warren Rossiter wrote a good article about Di2 in the February 2012 edition of Cycling Plus magazine. After starting off questioning its utility, he concluded

'...it doesn't take a huge amount of energy or effort to change gear now, so do we really need help? I can get quick, slick and positive shifting from the mechanical setups on my bikes but they do require regular tune ups and cables replacing. With electronic setups this hasn't been an issue thanks to the front mech auto trim. The ability to adjust gears on the fly with a press of the button and not an Allen key in sight is quite brilliant. Though the pros have used it already, I reckon it's us, the average cyclists, who'll benefit most. Powered shifting and auto-trim let you run extreme chain lines, big ring to biggest cog, and also handle shifting under load better. A mechanical shifter will often struggle if you make a change on a very steep climb; electronic just fires the chain across. As for charging, Di2 will run over 1,000km on a single charge and you can easily check the charge by holding the shifter for a few seconds.'

What's required to upgrade your bike to Shimano Ultegra Di2 shifting?

• Shimano Ultegra 6770 Di2 Front & Rear Derailleurs.
• Shimano Ultegra 6770 Di2 Dual Control STI shifters.
• Shimano Ultegra 6770 Di2 Control Unit with cables, Lithium-Ion battery and 90 minute fast charger (run distance: 2,000 km / 1,250 miles per charge.)

Edinburgh Bicycle support recycling electrical equipment.

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