Remember the patent story I wrote a year and a half ago that predicted all the latest wireless Di2 derailleurs, or the one more than two years back that teased 13-speed Shimano cassettes? Well, that early tease is getting supported by several recent partial slip-ups from several different companies in the bike industry. And it all points to a new Shimano GRX 1x 13-speed update on the near horizon, possibly with Dura-Ace 13-speed coming not far behind?
So what do we know?
Is Shimano going 13-speed with new MicroSpline Road freehub?
About a week ago, DT Swiss revamped their affordable aluminum 1800-series of road, endurance all-road & gravel bike wheels. Out of those three separate disciplines, only one, the gravel G1800, included a slightly new reference to the only quietly-previously-announced freehub standard. DT calls it “MicroSpline Road” in their press kit. We could have written that off as no big deal… if there wasn’t anything else floating around. Plenty of Shimano gravel groupsets were already using MicroSpline since GRX 1×12 shares wide-range MTB cassettes on MicroSpline freehubs.
Update: DT has confirmed that their MicroSpline Road freehub had already been around since GRX12 adopted the wide-range MicroSpline MTB cassettes. The reasoning was (as commentors suggested) to fill in the extra space outside of the shorter freehub body & cassette to fill in the road 142mm hub spacing. DT explains that if you fit a MicroSpine freehub body to their road/gravel hubs, “you would arrive at 140.9 mm” overall width, which would not be safe to use in a 142mm spaced frame. Even though that difference in width is very small, we can’t still help to think it might give Shimano more space to work with if they decide to go for 13 speeds!
So why a separate MicroSpline Road?
Even if iit’s just 1.1mm wider, it turns out the next one to reveal a bit more was German online retailer Bike-Discount.de.
They listed those new DT Swiss G 1800 Spline wheels with a bit more detail on freehub options, and some telling freehub body product codes. In addition to classic SRAM XDR (AXDR) & Shimano HG 11s (ASF11), we see two other options with very similar codes: Shimano MicroSpline 12s (ASL12R) & Shimano 13-speed (ASL13R).
Update: Another supporting document… a reader with a logged-in dealer account from bikeshop distributor QBP shared a screenshot of a listing for a current Shimano GRX RX820 crankset that lists 12/13-Speed in its product name.
The 12-speed MicroSpline seems to be the current MTB standard, and the new ASL13R appears to be the next-level progression that DT was calling MicroSpline Road (which DT confirms is the same MicroSpline proilfe, plus an additional 1.1mm to fill out the 142mm spacing on their road hubs). Similar product numbers would make sense for both being the same spline pattern. But this one goes to 13!
Why, you ask?
Perhaps a new 13-speed MicroSpline road freehub needs more space to fit that extra gear? Shimano, SRAM & Campagnolo have all used a few tricks in the past to fit more cogs of the same width in the same spacing before – sometimes pushing those cogs closer to the frame/dropout surface, and sometimes cantilevering them over hub flanges & spokes. The fact that Shimano would need another, slightly different freehub body suggests they couldn’t find more space with the existing MicroSpline, and needed to push it a bit further…
Shimano 13-speed isn’t guaranteed, but it’s not just speculation either
Shimano has been teasing us with 13-speed cassettes in the patent drawings for at least two years. They could have easily put 12 cogs on that cassette if they weren’t trolling us.
And in the meantime, both SRAM and Campagnolo have launched 13-speed gravel & road groupsets. So, it’s high time for Shimano to catch up.
When is it coming to gravel? And when will Shimano 13sp hit the road?
That’s something we don’t know. Shimano hasn’t told us when to expect a new dropbar groupset. Frankly, with fairly recent GRX 12-speed launches, we wouldn’t have expected a new Shimano gravel launch any time soon. But the fact that DT Swiss is debuting this new freehub body option only on their gravel wheels (and clearly not on the road & all-road variants) suggests gravel is likely to get 13-speeds first. That probably does make the most sense, giving more range or smoother gearing steps to 1x drivetrains.
Yet really, we’ve been waiting for a new Dura-Ace groupset for several years. DT is calling the new 13sp freehub ‘MicroSpline Road’ which sounds to us like it’s laying the groundwork for a 13-speed road groupset, too. The fact that we didn’t see it on pro bikes at this year’s Tour de France suggests it likely won’t be ready until at least next spring.
But let’s just say that Shimano & DT have piqued our interest. And we’ll be keeping our eyes open to spot an extra cog on pro road and gravel bikes over the next few months!
