Shimano RX800 Rear Derailleur

Shimano RX800 Rear Derailleur

At the beginning of last year, before Shimano came out with an entire gravel groupset, the Shimano RX800 rear derailleur was released specifically for gravel applications. Honestly, I was reluctant to buy into the need for a clutch derailleur, but there are more advantages to the RX800. So maybe it’s time for this road cyclist to take a look at some gravel technology.

The RX800 rear derailleur is Shimano’s nod to the popularity of gravel cycling, and it includes the Shadow Plus technology, or more simply stated, it’s a road derailleur with a clutch based chain tensioner. From Shimano’s point of view, this technology is designed to help minimise derailleur arm movement, and chain movement along with it, so as to reduce chain slap.

Not being a long time gravel rider, I kept looking, or more accurately, listening for this being a big issue in the time leading up to testing the RX800 rear derailleur. It’s not something I ever really found, though. My Cannondale Slate was running a 52/36 double chainring upfront and an 11-28 cassette in the back. This isn’t a setup with a particularly slack chain, and it lends itself to spending a lot of time in the small ring upfront.

Basically it’s not a setup that has strong need to reduce chain slap, but as I mentioned above, there are additional advantages to the RX800 rear derailleur beyond just minimising chain slap. The times I’ve experienced a dropped chain has always been times when there’s a fair bit of torque on the chain, and I’m dropping from the large to the small chainring upfront. It’s this situation where the RX800 really shines and honestly, makes it a great addition to every bike, gravel or not.

Think of times when you go from flat, or downhill, to a climb and you are working hard to carry speed. When you finally decide to drop down to the small chainring upfront, instead of the chain bouncing off the chainstay, or potentially bouncing off of the front chainring completely, the clutch on the RX800 keeps the chain tight and the shift smooth and quiet.

There is an off switch for the clutch, but I never use it, and I can’t really imagine a situation where I would. There might be some slight penalty in terms of drivetrain drag but not so much that I would bother messing with it. The other big reason that I finally decided the RX800 was worth taking a look at was its ability to handle a max 34 tooth cassette.

There are other derailleur options, without the clutch, that allow for a 34 tooth, but for gravel riding, the RX800 offers the advantages of the clutch plus the additional capacity, and there’s really no downside. AMain carries the RX800 for a price of $103.99, and it weighs in at 248 grams. If instead you were to choose the Ultegra level long cage rear derailleur from Amain, you’d only save yourself $12 and 38 grams.

Bottom line, I like a 2x setup for both road and gravel, and while SRAM has long offered a clutch derailleur for 1x systems, Shimano is offering a solution for those of us that prefer double chainrings upfront. With virtually no penalty in either price or weight, and both mechanical and electronic options, Shimano has come out with a great product regardless of whether you are shopping for a gravel bike or a more traditional road bike. I think the RX800 is a clear choice next time you are upgrading your rear derailleur, and AMain cycling is a great place to pick one up.

Typically when I bring you these reviews, I’ve partnered up with the manufacturers directly, but in this case, I was lucky enough to work with a really fantastic retailer called AMain Cycling. I’ve worked with Amain Cycling in the past for my own needs, and I’ve always felt well taken care of. Recently, another one of my favourite cycling retailers, Performance Bike, underwent some major changes and was absorbed by AMain cycling.

While the loss of brick and mortar Performance Bike stores is indeed a bit of a loss, AMain is now handling the online ordering for both Performance Bike and Bike Nashbar. No matter which site you place your order on, the same great people will be behind it. Given the inventory overlap that existed, this makes a lot of sense, and AMain continues to carry many well known brands, including Garmin, Specialized, and Shimano.


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