We’ve been deep in Di2 rumors ever since Shimano bypassed XTR and released an ebike-only XT Di2 groupset in 2022. And the rumor mill only got louder when a new 2x-only GRX Di2 launched last spring… not the 1x that most gravelers now prefer. So since then, I’ve been on the lookout for more Di2 patent stories to uncover more insight into Shimano’s development cycle.
But now our latest Patent Patrol finds line up with some of those rumors, and all hint of a huge update to Shimano Di2 mountain bike drivetrains coming soon….
Shimano XTR Di2 has been a long time coming!
It’s been almost 7 years since Shimano updated XTR with mechanical M9100. That top-tier mountain bike groupset is no slouch (still one of our favorites), and the mechanical 1x 12-speed drivetrain is still being raced to World Cup & Olympic wins many years later.
But it’s not electronic.
In the meantime, wireless SRAM AXS groups have dominated the electronic-shifting market off-road. AXS continues to offer easy-to-use drivetrains at a wide range of price points, all with simple cross-platform integration. SRAM has delivered countless wireless drivetrains that are easy for anyone to set up, effortless to shift, and can be readily mix-and-matched between road, gravel & mountain bikes.
They even used direct-mount wireless mountain bike and gravel bike drivetrains to push bikemakers to adopt their new UDH standard. All the way to the point that SRAM may soon come back to a more affordable, simpler starting point with a couple of all-new mechanical Transmissions.
But wait, Di2 has been around for something like two decades
We’ve seen wired electronic Di2 since 2009, and semi-wireless on the road since 2021.
I already wrote about a fully wireless Shimano MTB Di2 patent last spring. It even hinted at the possibility of jumping from the current XTR 12-speed, straight to 13-speeds. But a year later, its interesting discussions on semi-interchangeable batteries, more gears, and even wireless braking have yet to materialize.
Now, with another mountain biking season in sight, there’s been a flurry of new interest. I’ve been digging through patents as I look to find evidence for my long list of 2025 predictions. And I have to act fast, as new product announcements are ramping up.
What’s new in 2025 for Shimano XTR Di2?
These latest patent diagrams appear much more developed than the schematic drawings that we reported on last year. And they back up some of the rumors we’ve heard.
The same core concept is there, though.
- These new Shimano Di2 off-road derailleurs pack their control motors & step-down gears (blue) deeper into the B-knuckle than their road Di2 derailleurs – presumably for better impact resistance.
- They mount the battery (red) into an oversized outer parallelogram link.
- They still include a clutch (green) in the P-knuckle.
- And even though we’ve seen separate Shimano derailleur patents with UDH-compatible direct frame mounts (and B-tension screws), these latest illustrations all still mount to a conventional derailleur hanger.
What about XT Di2, Deore Di2 & GRX Di2, though?
Another key bit of information comes from a bike manufacturer’s prematurely leaked 2025 spec sheet.
There, one full-suspension XC mountain bike that launched in late 2023 last year, now gets 4 new Shimano build specs in the coming season.
- The top-tier Team build lists an as-yet-unreleased XTR M9200 groupset, specifically calling out a M9250 Di2 12-speed shifter & Shadow Plus derailleur.
- Both a second-tier Team and a third-tier RC build each get another new product family number – an XT M8200 groupset – again specifying its own M8250XT Di2 12-speed shifter & derailleur.
- Then, even the fourth-tier RC build features Di2 with a new Deore M6200 groupset, again noting a M6250 Di2 12-speed shifter & derailleur for the new Deore line. Below that, further models feature existing mechanical groupsets.
As for GRX Di2 1x… I’ll leave that entirely to my own speculation. Rumor had it that Shimano was waiting for the 1x electronic mountain bike derailleurs to launch before copying the same look and style for GRX Di2 1x. That’s no big surprise since mechanical GRX 1×12 RX820 is essentially a carbon copy of XT M8100.
Hunting more details on all of these, I also scoured FCC filings. And while filing photos are still protected by confidentiality agreements, Shimano received FCC approvals for 5 new Bluetooth/ANT+ electronic devices in the middle of 2024, including: a ‘motor unit’, a rear derailleur, a flat bar shifter, a second rear derailleur, and a new dual control lever.
All-new XTR brakes coming, too!
As for new mountain bike brakes, those are probably coming soon, and likely to both XTR & XT, as well.
The key tech innovation in Shimano’s latest brake patent filings is a new lightweight 4-piston layout with one pair of larger ≥19mm pistons that are at least 15% larger than a smaller set of pistons. The claimed benefits include either an increased braking force or a reduction in the amount of hydraulic pressure required to brake. Then additionally, the different piston sizes and their new hydraulic layout also promise more even pad wear and/or improved long-term disc brake caliper durability.
That’s it for new Shimano mountain bike teasers for now. There’s a lot to digest.
We’ll be keeping a close eye out in the XC, Enduro & DH World Cup pits at the start of the season in a few months to see if we can spy some of these goodies up close.
