Description Electronic goes affordable.
Shimano's Ultegra Di2 6770 Rear Derailleur doesn't rely on cable tension, indexing and a spring to control rear derailleur shifts. Like their flagship Dura-Ace Di2 unit, an electronic worm drive is used to eliminate the pull and pull-back associated with a derailleur spring and cable. Once properly set up, the digital derailleur shifts with ultimate precision every time.
In the event of a crash, a saver function allows the derailleur to move in towards the wheel and away from the force of impact. Then it automatically resets itself with the push of a button and a few gear changes. If the auto reset fails, a manual reset is possible via buttons on the battery harness module near the stem and handlebar junction that work much like a barrel adjuster for fine tuning.
Limit screws are still set manually, and the RD-6700's outer materials are identical to the standard 6700 series mechanical unit. Slightly larger internals add a few extra grams compared to the Dura-Ace Di2 model while significantly lowering the price.
The RD-6770 is available in a short cage version only and is compatible with Shimano 10-speed cassettes with a max cog size of 28t. Sold as derailleur only with no cables. 270g.
Note: The RD-6770 is not compatible with Dura-Ace Di2 shifters or wire kits.
Articles A description of the different types of bottom brackets, the bearings for bike cranks.
You wanna go fast? Join the ceramic revolution!
An introduction to road bike cranksets.
