Shimano 12-speed reaches new Deore mountain bike groupset

by Dave Rome


Slow to return SRAM’s aggressive serve, Shimano entered the 12-speed mountain bike market in 2018 with XTR, and then followed up with XT and SLX shortly after that. Now, 11 months later, Shimano has announced the same 12-speed technology for its mass-market Deore groupset, a group that’ll surely find its way onto many well-priced mountain bikes for 2021.

Deore has a long history as the true starting point in Shimano’s mountain bike groupset range. Sure there are lower group options available, but Deore has long stood as the point at which recreational components end and performance begins.

And while Shimano Deore faded in popularity — with its 9- and 10-speed offerings looking dated next to SRAM’s affordable SX and NX 12-speed groups — it seems Shimano is now back with a vengeance. Shimano hasn’t just released one version of Deore; it’s released three, with new 12-, 11- and 10-speed options available under the Deore label.

Let’s delve into the details.

New Deore 12-speed is like XTR, or XT, or SLX, but cheaper

For those familiar with the latest XTR, XT and SLX 12-speed groups, the new features to Deore won’t come as any surprise. As a result, I’ll keep this article a little brief as the “why” and “what” behind the technology has all been covered previously with the launch of XTR M9100.

Like the more expensive options, the new Deore sees an emphasis on 1x shifting with an enormous-range 10-51T cassette. Also like its more expensive siblings, Deore requires the use of Shimano’s new MicroSpline freehub fitment; thankfully something that is now far, far more widely available than when XTR launched.

Shimano’s new 12-speed Deore group is 1x only.

And here’s perhaps the best part: All of these similarities mean that new Deore is fully cross-compatible with XTR, XT and SLX 12-speed components. Mix-and-match as your heart (and budget) desires. Equally as good are the colour-shifting graphics used, which change hues based on light angles.

However, where XTR, XT and SLX haven’t completely killed the front derailleur, new Deore 12-speed M6100 is all-in on 1x.

The Deore M6100 12-speed crank features a direct-mount chainring and is available for single chainring use, only. Chainring options are currently limited to 30 and 32T sizes only, and the cranks are only available in 170 and 175 mm lengths, too. There are, however, cranks offered with 52, 55 and 56.5 mm chainlines to suit 142, 148 (Boost) and 157 mm (Super Boost) rear wheel axle fitments. An M6100 crank with a 32T chainring and 175 mm arms weighs 763 g (SLX is 631 g).

The cranks feature a direct-mount chainring, but the chainring itself isn’t one-piece, but is rather two-pieces pinned.

The new M6100 10-51T cassette uses the same “HyperGlide+” shift technology that’s designed for smoother shifts under load. This cassette features all-steel cogs, and so carries a not-so-small weight of 594 g (SLX is 534 g, and XT is 470 g). The matching chain also features the same elongated inner plate link and quick connection link like more expensive versions but does so with a cheaper finish and fewer pieces treated to low-friction coatings.

The new rear derailleur looks rather slick and features the same clutch and low profile design as its siblings. Similarly, the pulley wheels are also enlarged to a more efficient 13T size. At 321 g, it’s only five grams more than an SLX rear derailleur.

The shifter is now a close match to more expensive options.

The derailleur matches to a new shifter that offers Shimano’s push-or-pull downshift lever, and there’s an optional optical gear display, too. The new shifter is available with either a band clamp or I-Spec EV mount to integrate with Shimano’s new brakes. There’s a matching dropper post lever, too.

The M6100 brakes also get the same treatment as the latest XTR, XT and SLX options, including the choice of two- and four-piston brake calipers, a reduced free stroke, an optimised lever axle position, and a stiffening rib that sits against the handlebar. Both the two- and four-piston callipers feature straight-path inboard hose routing.

Four-piston caliper brakes have quickly become the common pick amongst trail and Enduro riders. The two-piston remains the lighter option for cross country.

Finally, Shimano is offering matching 12-speed hubs (MT410). These feature a pawl-type engagement (36 points) and should be one of the more affordable entries into MicroSpline.

Pricing wise, new Deore M6100 is certainly cheaper than SLX, but not significantly so. And this makes sense given Deore’s somewhat OE (original equipment) focus. Shimano SLX, XT and XTR will realistically continue to be the more popular picks for those seeking aftermarket purchases, but Deore does open up further possibilities to keep the budget down.

Shimano’s Deore M6100 components are available now.

USD and AUD prices for Shimano Deore M6100 and SLX M7100
Pricing comparison between new Shimano Deore M6100 and SLX M7100.

M6100 vs M5100 vs M4100

Twelve rear cogs may be the big story for Deore, but Shimano has in fact released three versions of Deore: M6100, M5100 and M4100, which are 12-, 11- and 10-speed respectively. In many ways, the new 11- and 10-speed options are designed for the OE market, while also bolstering Shimano’s replacement part options for existing Shimano 10- and 11-speed drivetrain users.

These new 10- and 11-speed options use the same gear pull ratios and chain thicknesses as the existing respective 10- and 11-speed Shimano options, and so mixing and matching is certainly an option. And you may want to do just that given the boost in range these new options provide.

Shimano’s new M5100 group brings many of those same features done to 11-speed, and with a regular old freehub body.

Shimano Deore M5100 (11-speed) offers both 11-51T and 11-42T cassettes, with the former designed for 1x use only. That’s a noticeable update from Shimano’s previously largest 11-46T 11-speed cassette. Better yet, these cassettes use Shimano’s older HG freehub body standard (the one your old bike likely has). To use that 11-51T cassette, you’ll need the new M5100 11-speed-specific rear derailleur, something that looks almost exactly like its 12-speed counterpart.

Meanwhile, Deore M4100 provides a boost in range for 10-speed users. Those using a single chainring can use the new 11-46T cassette, and there’s an 11-42T cassette option for those on 2x setups. These new cassettes come with two new rear derailleur options: the M5120 (which has a clutch) is designed for use with 42-46T cassettes, while the M4120 (no clutch) has a maximum cog limit of 42T. Oddly, both of these derailleurs are compatible with both 10- and 11-speed shifters.

Shimano’s new 10-speed Deore M4100 has both 1x and 2x options. The same applies for the 11-speed M5100 variant.

Clearly those seeking front derailleurs haven’t been left out, and both M5100 and M4100 have 2x gearing options. In both cases, the cranks only offer 22/36T chainrings, while the M5100 shift lever features Shimano’s new and simplified off-on Mono design.

No word yet on pricing or weights for these components, but you can bet they’ll be everywhere on entry-level mountain bikes.

The hierarchy of new Deore.

Flat mount for MTB?

That’s right, road-specific flat mount disc brake mounts are slowly trickling into the mountain bike realm. Both Cannondale and Canyon are already using such things on certain XC models, and surely there will be more to follow.

Personally I greatly prefer working on a bike with post mount (or even older IS mounts) than I do flat mount frames, but still, flat mount has its advantages. With less additional material reinforcement required and a slimmer overall profile, flat mount opens up a handful of new frame design options. And all of that could potentially offer some big benefit to full-suspension frame designs that are currently quite limited for where the brake caliper has to go for ensured fitment and easy adjustment.

Shimano is now supporting flat mount on the mountain bike side, too.

With all of this, Shimano has released flat mount variants of its two-piston XTR, XT and SLX disc brake callipers. The XTR version (M9110) is designed for a maximum of a 160 mm rotor, while the XT (M8110) and SLX (M7110) variants can handle either 160 or 180 mm rotors. Clearly these products are designed specifically for cross country usage.

New cranks, STEPS e-bike stuff, and more

But wait, there’s more.

The announcement of new Deore 12-speed comes with matching MT601 wheels. They’re available in 27.5 or 29in rim sizes, and in either Boost or regular thru-axle spacing and offer a cheap entry into the MicroSpline freehub platform. Specific details are scarce at this time.

Shimano has announced a new XTR crank (M9130) for use with Super Boost frames (56.5 mm chain line). This crank is 1x-only and seeks to offer a narrow Q-Factor by borrowing the low-profile arms of the regular 9100 crank.

There’s also a new Deore-level 2×12 speed crank with 26/36T chainrings. As a cheaper alternative to SLX, I suspect this crank will be popular on certain off-road-focussed bikepacking rigs.

There’s an update to Alivio, too.

Shimano has also updated its entry-level Alivio and Tourney groups, giving them some of the stylish features found in newer 12-speed groups. New Alivio M3100 is available in 2×9 or 3×9 variations, with new low-profile (Shadow) derailleurs and the Mono left shifter trickling down.

Meanwhile, Shimano’s cheapest component offering which is commonly found on kids bikes, Tourney, gets a freewheel with better corrosion resistance, an updated grip-style shifter, and new derailleurs, too.

Finally, Shimano has announced a few small updates to its STEPS e-bike offerings. There’s a new largest-capacity-yet 630 Wh battery, new Super-Boost-compatible 12-speed e-bike chainrings (34 and 36T options), and a new integrated handlebar display and control unit for urban e-bikes.

Our sister site, Pinkbike, checked out the new Deore group here:

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