Shimano GRX RX820 - first look

Alex Paton takes a ride on Shimano's new 12-speed version of their flagship product

Clock16:39, Thursday 31st August 2023

Shimano have updated their GRX mechanical gravel groupset, with the 800 and 600 series moving to 12-speed.

For the time being at least there is no update to the GRX Di2 groupset with the RX820 flagship 12-speed range currently only available as a mechanical group.

The new range is offered to customers in three ‘personalities’ to suit the type of rider you are, and the terrain that you ride on. They are what Shimano are branding as 'Unbeatable', 'Undroppable' and 'Unstoppable' each with a unique set-up for the demands of the rider. You can find out more about the specifics of each ‘personalities’ in the full product release linked here.

Not only has the top tier RX820 seen this overhaul to 12-speed but so has the more budget-friendly RX610 range as well, bringing 12-speed gravel to a far wider market.

This comes on the same day that Shimano release their first 12-speed mechanical road groupset with 105 mechanical, which you can read all about here.

The final part of the new GRX range is an updated gravel-specific carbon wheelset, the RX880. This features an easy-to-swap-out freehub body and a shallow rim profile to aid acceleration, once again more about these wheels can be found here.

What is on offer?

GCN's Alex Paton managed to get a ride on Shimano's 'Unstoppable' groupset, which is aimed at riders at the more extreme end of the gravel spectrum. It features a 1x12 setup with a wide ratio 10-51 tooth cassette and a clutch-enabled rear derailleur to keep the chain tight on rough gravel sections.

The Unstoppable personality is intended to be run with either a 40 or 42 tooth chainring and the cranks are available in three lengths: 170, 172.5 and 175mm.

For some, it might seem like an overwhelming amount of choice across the three personalities, especially given the chainring and cassette options on top of that, however the large range of options means any rider can find the ideal groupset for them. Shimano have said that "the new 12 speed GRX lineup delivers more gearing options, along with unrivalled ergonomics so riders get the most out of each unpaved adventure, whatever that might be."

The idea behind the personalities is that the new GRX range can accommodate whatever gravel riding means to you: it can be used in your local gravel ride, on an adventure ride or a multi-day bikepacking epic. Shimano are really steering in to the diversity of what gravel riding can be to different riders.

New levers

The ergonomics of the new GRX RX820 levers have also seen a redesign, interestingly, the engineers at Shimano have managed to keep the lever the same size whilst increasing its capacity for 12-speed shifting. The levers have also been designed with flared bars in mind, something that is very popular in gravel riding as it allows for increased control when riding technical sections.

There are also a couple of lever options that can be selected to go along with the groupset personalities. There is a traditional 2x12 set up that has traditional Shimano shifters, however for the 1x12 groups you have the choice of either one shifter or dual shifters with the left hand on operating a dropper seat post.


Shimano recently revised the braking platform of the outgoing RX800 groupset back in 2022. This saw the calliper design slim down on the previous version as well as increasing pad clearance by 10 percent. The brakes can be run with either a road or mountain bike disc in either a 140mm or 160mm diameter depending preference as Shimano don’t offer a gravel specific disc.


It was only just over a year ago that Shimano released their first gravel specific carbon wheels, however that hasn’t stopped them from giving them an overhaul with the rest of the GRX range. The wheelset is lighter than the previous model, but there are no changes to the rim itself, remaining 32mm deep and with a 25mm internal rim width. This allows for a 32mm tyre all the way up to 50mm to be fitted.

The area that sees change is the hub, using a direct engagement freehub similar to that found in Dura-Ace road wheels as well as a slimmed down body this is where the weight savings are made. The total wheelset weight for the RX880 with a Shimano microspline freehub body comes in at 1397 grams.

For a full rundown of the groupset checkout our new article detailing the specifics of the new groupset as well as Alex’s first look video linked at the top.

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