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Shimano launches new Ultegra RX 'clutch' rear derailleur

Joe Robinson
3 Apr 2018

Straight from the world of mountain biking, this new technology for the road bike is bang on-trend

Shimano has officially launched its Ultegra RX clutch rear derailleur, the chain stabilising rear mech that follows the growing trend of road bikes going off-road.

The mechanism was spotted last weekend at the Tour of Flanders and now the Japanese component giant has officially released this new technology which will also be targeted at adventure, gravel and cyclocross. 

The technology has been transferred across from the world of mountain biking, in which clutch rear derailleurs have been vital in the growth of 1x groupsets and the trend of riding cassettes with bigger ratios.

However this latest design from Shimano has been designed to work with a traditional double chainring.

The reason being that Shimano wanted to prevent 'chain chatter'. So with the development of its Shimano Shadow RD+ switch, a button placed next to the upper pulley, more control over the drivetrain will be given to the rider over uneven surfaces which when activated will prevent 'excessive movement' from the chain and the pulley cage being sprung forward.

This will result in fewer mis-shifts and less chain drop while also helping secure a greater amount of chain to be in contact with the cassette while bouncing on rough surfaces. 

Logic tells us that this development will pave the way for more 1x groupsets within the professional road peloton and it is likely that we will see teams running this new system at this weekend's Paris-Roubaix, scrapping their unnecessary inner chainring with the lessened chance of chain slip. 

For the time being, Shimano will see this new RX800/805 rear derailleur accommodate cassettes up to 28t for medium cage and 34t for long cage for both mechanical and electronic Shimano drivetrains.

It is expected to be in stores from mid-June onwards.

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