As road bike riding diversifies towards multiple road surfaces such as adventure and off-road riding Shimano introduces Ultegra RX, an off-shoot of Ultegra, with a rear clutch derailleur (RD-RX800/RX805) for mechanical and Di2 drivetrains.
Riders have been pushing the limits of what a road bike is capable of riding for many years, evolving the sport from racing to encompass greater adventure. In recent years we’ve seen a broader definition of what a drop handlebar bike can look like; road wheels followed that by accommodating wider tyres. Now in a natural evolutionary step, it’s time for drivetrains to evolve too.
The new RX800/805 rear derailleurs share many characteristics with the Ultegra R8000/R8050 derailleur, such as precise accurate shifting and SHIMANO SHADOW RD derailleur positioning, but with the added chain stabilizing switch (known as SHIMANO SHADOW RD+ technology) to control the drivetrain over rough/uneven ground or off-road surfaces. Much like Shimano’s MTB derailleurs, the On/Off switch can be found next to the upper pulley. When activated the rear derailleur pivot takes a firm hold to reduce excessive movement, noise and general ‘chain chatter’.
The RX800/RX805 rear derailleurs are compatible with road dual control levers (mechanical or Di2) and will accommodate cassettes with low gears from 28T to 34T, making them a very necessary addition for all types of adventure and off-road riding including cyclocross and compact styles with 46T-36T up to 50T-34T chainrings.
Alongside the Ultegra RX rear derailleur comes a new wider rim 700c, E-Thru axle, tubeless-ready, disc-specific, WH-RS370-TL aluminium wheelset for 28-38c tyres (weight 1900/pair).
You can expect the new components to be available in stores from mid-June 2018 onwards.