Images published by sister site Cyclingnews, show what appears to be a new Shimano Dura-Ace groupset being ridden at the Vuelta a Espaa. The new groupset features a 13-cog cassette, integrated satellite-hood shifters, and possibly a new freehub. But it still appears to be semi-wireless. Given these sightings follow the official launch of the Dura-Ace R9370 wheels and months of online leaks and speculation, we imagine this is the R9300 version of Shimano's flagship road groupset.12 to 13-speed The Japanese brand appears to have added a cog to the currently 12-speed Dura-Ace cassette, joining Campagnolo in offering a 13-speed road groupset (SRAM only has a 13-speed gravel groupset, XPLR AXS). A 13-cog cassette reduces jumps between gears and increases range in a two-bydrivetrain. It is even more beneficial in a 1x setup. This could indicate Shimano is going to make single chainrings for the new Dura-Ace. Until now, the Shimano-equipped pro teams have resorted to aftermarket chainrings to run one-by, while SRAM and Campagnolo supply single rings dedicated to road use. A new freehub?The move to a 13-speed cassette may require a new Shimano freehub, as the leaked listing of a DT Swiss freehub body suggested, especially if it has a 10T smallest cog. Shimano looks set to decrease this from 11T to close the gear-range gap with SRAM. This would force users of wheels fitted with Shimano's current road standard, HG for 11-speed and 12-speed drivetrains, to convert their freehubs to use the new Dura-Ace. When SRAM introduced a 13th sprocket to its XPLR cassettes, it maintained the same spacing as its 12-speed road groupsets so they both could use XDR freehubs. Meanwhile, Campagnolo's 13-speed N3W freehub is backward-compatible with older 9-, 10-, and 11-speed cassettes. But because Shimano has already found space for an extra cog on its HG freehubs with the current Dura-Ace Di2 12-speed, it may be difficult to repeat the trick. A new rear derailleur but still wiredThe new Dura-Ace rear derailleur spotted on the bikes of riders from Team Picnic PostNL and Alpecin-Premier Tech appears to have a slimmer profile and diagonal cut-outs near the charging port, suggesting it could be lighter than before. From what we can see, there is nowhere for an external, removable battery to go, like on SRAM's AXS derailleurs. The absence of a battery and the presence of a cable running from the drive-side chainstay suggest that Shimano has retained the Dura-Ace R9200's semi-wireless design. This allows the shifters to communicate wirelessly with the derailleurs, which are connected to a battery stored in the frame. Because Shimano's latest electronic gravel and mountain bike rear derailleurs are wireless and it has filed a patent for a wireless 13-speed road groupset, it seemed a done deal that the new Dura-Ace would be free of wires. So why doesn't that seem to be the case? It's handy to be able to charge SRAM's removable derailleur batteries off the bike, but their runtime is shorter than that of the single battery currently used in Shimano's Di2 electronic groupsets. In addition, the external battery makes SRAM derailleurs bulkier than Shimano's, and possibly less aerodynamic as a result. In-built satellite shifters Shimano appears to have integrated satellite shifters into the inside of the new Dura-Ace Di2 shifters. As well as the paddles and hidden buttons on top of the hoods, these now appear to have a small lever on the inward-facing side of the pommel. It remains to be seen whether these miniature paddles will replace the hidden buttons on top of the hoods featured in the current groupset, or exist alongside them. Both SRAM and Campagnolo have their own versions of these bonus shift buttons, which help riders seamlessly change gear when climbing out of the saddle on the hoods or when adopting the aero-hoods position. New power meter and cranks?We can't deduce much from the pictures of the cranksets on these bikes, which are fitted with other seemingly new Dura-Ace parts. Cyclingnews reported that the black cranks, which look similar to the existing version, are attached to off-brand chainrings on AlpecinPremier Tech's bikes. The cranks themselves could still be prototypes like the unreleased SPD-SL pedals that have been raced this season. We do, however, understand that Team PicnicPostNL is using an updated Dura-Ace power meter. Shimano will have tried to improve the doubtful accuracy of the current generation. What is Shimano saying?A Shimano spokesman said: "Shimano is constantly developing new products, but does not comment on rumours, speculation, or unannounced products.