Shimano drops two 12-speed GRX groupsets, new gravel wheels

Shimano is having a busy day. Alongside the just-announced launch of the new 12-speed mechanical 105 road groupset, the Japanese brand has also unveiled a spate of new gravel tech, including two new 12-speed versions of GRX, as well as a new set of carbon gravel wheels.

Starting with the groupsets, they come in the form of the higher-spec RX820 series and the more affordable RX610, but besides some specs, material choice and the associated weight difference, they both provide a similar solution to gravel riders' needs, offering 12-speed cassettes in 1x and 2x configurations. 

Notably, they are both mechanical, meaning anyone holding out for 12-speed GRX Di2 will have to continue playing the waiting game. It also means the entry-level RX400-series remains unchanged. There's no news as to whether either will see an upgrade in the near future. 

In both cases, the big talking point is the enormous gear range available, with up to 10-51T cassettes in what will be a mountain bike-like gearing setup. 

Shimano GRX RX820 details

Whereas the outgoing 11-speed groupset topped out at 11-42T in cassette size, the RX820 groupset will now come with a choice of two even-larger cassettes. These are 10-45T or 10-51T in size, meaning an increase at both ends, providing more top-end speed, and bottom-end range to winch up steep inclines. 

I mentioned it being a mountain bike-like setup earlier, and the cassette in question is in fact from Shimano's mountain bike range. Both are from the M8100 XT range and use Shimano's Microspline freehub interface. 

There's a bit of complexity to get your head around when it comes to choosing your rear derailleur. The 10-51T cassette will need to be paired with the RD-RX822-GSG derailleur, essentially a long-cage version, while the 10-45T will need the medium-cage RD-RX822-GS. 

Notably, and thankfully, the derailleur cage alone can be swapped or replaced, meaning you don't need to buy a whole new derailleur in the event of a cassette swap (or a crash). 

Up front, the Shimano Hollowtech II 1x chainsets come with a choice of two chainring sizes, 40T or 42T, and three crank lengths (170mm, 172.5mm and 175mm). 

For those who prefer 2x, you're limited to just one chainset option. That comes with 48/31T chainrings and is paired with a choice of 11-34T or 11-36T cassettes. This will require a third derailleur, the short cage RD-RX820 with a maximum cassette compatibility of 36T. 

The same choice of crank lengths is available, and to enable wider tyre clearance, the chain line is pushed outward by 2.5mm when compared to road groupsets, as per existing GRX. 

Shimano also says the new RX820-Series groupset has been given updated shifters with improved ergonomics that have been optimised for comfort when used with flared handlebars, as are often found on gravel bikes. Like the outgoing GRX groupset, the 1x groupsets can either be specced with a left-hand shifter for dropper post control, or as a brake lever only. 

Shimano GRX RX610 details

The RX610 series is designed to mimic the RX820 groupset but for the more budget-conscious rider with cheaper, heavier materials. Much of the functionality is alike, although there are a few spec differences, such as available crank length and chainring sizes, to share. 

Starting with 1x groupsets, the same 10-45T and 10-51T cassette ranges are offered, but in a Deore M6100 component level, rather than the XT M8100 as above. Again, this uses the Microspline freehub. Unlike the RX820, one rear derailleur fits both of these cassettes, the RD-RX822 GS long-cage option. 

Up front, the 1x chainset comes with two chainring options. These are 38T and 40T rather than the 40T and 42T offered above. There's also an extra crank length option of 165mm, meaning four in total (165mm, 170mm, 172.5mm and 175mm). 

For 2x users, the same four crank lengths are offered, but chainring configurations are limited to just one option. This is 46/30T, but mixing and matching with the above series will open up more choices. There's also only one cassette offered, an 11-36T, but again, the 11-34T cassette from above will work. 

The shifters are also available in a 1x or 2x compatible format, with the latter foregoing the left-hand shift mechanism in favour of a brake lever only. 

Shimano RX880 gravel wheels

Last but not least in Shimano's big day of launches is a new pair of gravel wheels. These are an update to the RX870 wheels launched in summer 2022, and are a small evolution rather than wholesale revolution. 

They boast the same fully carbon 32mm rim as before, complete with 25mm internal width, but Shimano says it has managed to shave 64 grams from the weight, bringing it down to 1,394 grams with a Microspline freehub, or 1,397g with HG L2 freehub.

The wheels are designed for use with tyres between 32 and 50mm, have full carbon fibre rims, and are laced using 24 j-bend spokes front and rear. They borrow Shimano's 'Direct Engagement' star ratchet engagement from the flagship Dura-Ace wheelset. Cyclingnews understands the wheels continue to use cup and cone bearings in favour of cartridge bearings. 

Specs, pricing and availability

Groupsets and wheels will be available via OEM immediately at launch, followed shortly after in retail stores as a standalone aftermarket buy. Pricing and availability for GRX RX880 wheelset is to be confirmed.