Both models come with a GS long cage that fits cassettes between 11-28t and 11-34t. Lawrence explained the company added room for the 34t cog after test rides on the steep gravel roads in Colorado. That’s pretty low for road 2x gearing, but a few steps away from the 11-42t many 1x users are used to (in case you’re thinking about a RX805 single chain ring setup). Some readers will likely note Shimano already has clutch mountain bike derailleurs that can be paired with electronic shifting for 1x systems. With the new Ultegra RX derailleur, Shimano expands compatibility to mechanical road shifting and suggests there is a benefit in having a clutch rear derailleur with double front chain rings when riding gravel. Shimano also had its pro team liaisons at the Almanzo event. They were somewhat mum on the Ultegra RX’s future in professional road and cyclocross racing. Word about the Ultegra RX first came out when the Trek-Segafredo team test rode the clutch-based derailleur before the Tour of Flanders spring classic. The team did not race with the Ultegra RX in Flanders, but they did at Paris-Roubaix. As one of the reps pointed out, the impact of the new derailleur did not show in the results. A number of European cyclocrossers, including Mathieu van der Poel, Sanne Cant and the Telenet Fidea team, race on Shimano components. Although SRAM’s clutch-based derailleurs have become a favorite for many U.S. cyclocrossers, the Shimano reps said none of the athletes have committed to using the new clutch-based system this fall.

Overall, shifting on the new derailleur feels improved rather than drastically different — the feel at the lever is slightly lighter and overall more satisfying, with an absolutely delightful metallic ‘cla-chunk’ as the chain climbs the cassette. As part of the trip to Spring Valley, MN, I joined other journalists in racing the Almanzo 100 gravel race on an Allied Alfa All-Road bike equipped with the new Di2 Ultegra RX805 rear derailleur. By chance, I got the opportunity to experience the gravel life with both a non-clutch Dura Ace R9150 rear derailleur and the new RX805.I love using R8000, it's pretty much my favourite groupset – and I've ridden virtually every setup going this year, at least from Shimano and SRAM. It's no lighter than the outgoing edition, but overall it works just a little bit better – more an exercise in refinement than a major overhaul, but very welcome nonetheless. Verdict However, much to my chagrin there’s still no sign of a clutch equipped — or Shadow Plus as Shimano calls it — rear derailleur that is directly compatible with Shimano’s road shifters. 1x for the road without resorting to Di2 or cable pull adaptors would be great, so can we please have this soon, Shimano? Price Matches may only be honored on identical items. The product must be the same make and model (i.e., the same size, color, year, etc.). Particularly when I am on the big ring, and the 5 smallest gears, the transmission produces a noise which seems to come from the rear derailleur (and more precisely at the level of the top pulley, where we see the chain that seems to "vibrate" - see video). The added weight for the clutch is about 30-40g. The RD-RX805 model has a claimed weight of 280g (compared to 249g for the RD-R8050) and the RD-RX8050 weighs 248g (compared to 210g for the RD-R8000).

Shimano Shadpw RD -The mechanism rear derailleur, SHIMANO SHADOW RD, is intended for more aggressive riding. Its super low profile design carries many benefits. Because of its low profile and single tension construction, the derailleur does not hit the chain stay in rough riding conditions. The result is smooth and silent performance. Ultegra R8000 is best seen as an overall refresh of the venerable Ultegra 6800 groupset rather than a drastically new design — lots of small refinements make the groupset an absolute joy to use with braking and shifting that is largely indistinguishable in performance from Dura-Ace 9100.

All specifications

For me, the biggest difference of R8000 over 6800 is the shape of the brake lever. The curve for your index finger is more pronounced and if, like me, you like to wrap your finger around the bar when on the hoods then you'll find it very comfortable.

All the prices listed here are the official Shimano recommended retail prices and as we all know you can get things like groupsets a lot cheaper online. Accurate, dialled and metered shifting from a mechanical rear derailleur, the Shimano Ultegra R8000 11-Speed Rear Derailleur, GS provides neat, crisp and clear-cut shifting prowess to the rider looking for pinpoint accuracy in their rear derailleur.

Ultegra R8000 verdict

The materials which this derailleur is made from are lightweight and durable. Light metals are used which makes the derailleur very strong. These metals are optimally constructed and finished so that you don't take a gram to many up the mountain with you. Shimano has made no specific claims as to how much stiffer the new R8000 brakes are over the outgoing 6800-series model, but the latest Dura-Ace brakes are reported to be 43 percent stiffer than the previous generation, so we can likely expect similar claims here. Potenza is a very good groupset, but when I tested it, it was pitched against Ultegra 6800 and this new R8000 group has moved things up a notch. I appreciated the wide range of the 11-32t cassette the long-cage GS derailleur supports, especially in the last 20 miles of the race. Our Allied Alfa All-Road test bikes had a compact 50/34t Dura-Ace crankset paired with an 11-32t rear cassette, which provided a very spinny 34/32 climbing gear ratio compared to the 36/28 of my personal cyclogravel bike. Several members of the team rode the new Shadow RX derailleur at the 2017 Almanzo 100, but rain and temperatures that hovered around 40 degrees forced many of the team to skip the race or withdraw early. All told, only about 100 starters finished the event. Not exactly the best test conditions.