top of page
  • Writer's picturedirtyheart

12-speed Shimano XT and SLX is here

Finally… let the mountain bike drivetrain war begin anew. After spending several years off the back of the 12-speed-wide range-1x race, Shimano can stand shifter to shifter with SRAM, following today’s launch of new XT and SLX groupsets. Yes, we know that 12-speed XTR was announced last year (and is finally coming available now). But without a more affordable every-rider option, the Japanese component maker remained on the back foot. That all changes now — and unlike the clunky and protracted XTR rollout, new XT will be available globally in just two weeks on June 14, with SLX following in July.

Like XTR, the centerpiece of these new offerings is a 12-speed 10-51 gear range that offers just a touch more breadth than SRAM’s wildly popular Eagle 10-50 drivetrains, which heretofore had essentially taken over all OE spec on new mountain bikes. Soon, though, legitimate choice will be returned to the market, and Shimano is optimistic that there will be compelling reason to pick them.

“In our mind it will go back to the traditional Shimano hallmarks of technology that goes above and beyond just function,” said Nick Murdick, mountain bike product manager for Shimano North America, who presented the two new groups at a press event in Bellingham, Washington. “We really feel like when people ride HyperGlide+ and see how much it improves shifting performance, and they get a feel for how awesome our brakes are, and then they see the durability and quality control, and how we stand behind the things that we make, it will be an easy choice. We really take pride in the fact that our products won’t just perform well when they are new, but they’ll do it for many years to come without the need for constant adjustment.”

That entire statement, of course, is a not-so-veiled shot at SRAM, which for all its innovative genius, sometimes suffers in the long term performance realm. And even if you’ve never had to struggle to keep you XO1 rear derailleur shifting properly, there’s no denying that in the end the consumer benefits from increased competition.

All that said, Mtbr has yet to formulate any meaningful long term opinion on any of Shimano’s 12-speed groups. But based on our limited test time on XTR last year and XT at the recent press launch, it’s clear they are at least back in the game. In Bellingham we spent two longs day aboard an Ibis Ripley spec’d with full XT and found that while not quite as precise and crisp as the XTR group we tested last year, the second-tier offering delivers as promised. Shifting was reliable and predictable, even when we tried to mess it up by pedaling and shifting at the same time.

The gear range (510% to be exact) was more than adequate for the numerous steep climbs, and the brakes were flawless, never fading even on extended unfamiliar descents. I also (re)realized how much I love 2-way and multi-release, a feature not found on SRAM Eagle. My only immediate gripe was with the PRO dropper post lever, which was a tad short and positioned too close to the bar for my liking. Mtbr has a test group on order and will publish a longer term review in due time.

In the meantime here’s a rundown from Shimano on the key features of the new XT group. You can read about the very similar, but slightly heavier and less expensive SLX group here.

Meet the New Shimano XT

Employing the latest technologies and performance from Shimano’s flagship XTR mountain bike components, the new Shimano XT series features 12-speed versatility along with top tier shifting and braking. Where the latest XTR is aimed at the racing crowd, Shimano XT M8100 is more trail focused, from wide rims to trail-tuned brakes and gearing options with ergonomics that prioritize comfort and control. Other improvements include:

• Refined SERVO-WAVE brake levers that match up with next generation I-SPEC EV RAPIDFIRE PLUS shifters featuring INSTANT RELEASE, 2-WAY RELEASE, AND MULTI-RELEASE giving the rider more control and confidence.

• The CN-M8100 chain’s extended inner link plate is a key component of smooth HYPERGLIDE+ shifting and improved chain retention of Shimano’s DYNAMIC CHAIN ENGAGMENT (DCE+) single front chain rings.

• The new construction of the low-profile RD-M8100 SHADOW RD+ rear derailleur improves shift quality, range of adjustment, and chain retention while allowing for a wide range of gearing options.

• Delivering multiple drivetrain options, Shimano XT offers a range of gearing choices including wide range (10-51) and rhythm step (10-45) cassettes with single and double front chainrings (yes, apparently some people still like front derailleurs).

HYPERGLIDE+ Technology

Inheriting HYPERGLIDE+ technology from XTR M9100, the XT M8100 group uses redesigned chain plates and shift ramps which guide the chain both up and down the cassette providing faster, smoother shifting in both directions.

Adding to DEORE XT’s M8100 revamped drivetrain transmission, the new CN-M8100 HG chain features SHIMANO’s DYNAMIC CHAIN ENGAGEMENT (DCE+) technology where an extended inner link plate of the chain connects seamlessly with new chainring tooth shapes for better chain retention and smoother, quieter pedaling. The new design reduces natural vibrations normally caused by the inner and outer chain plates rolling onto the chainring while also providing stronger contact between the two components.

Drivetrain Components

M8100 HOLLOWTECH II crank construction offers a lighter and stiffer crank design with options for both front single and double chainrings in three Q-factor options, including a Super Boost option (172mm, 178mm, 181mm). Chainrings are easily exchanged with the new direct-mount system and the cranks can be swapped between single and double front chainring setups.

All Shimano 12-speed direct mount chainrings are interchangeable. Additionally, Shimano refined chain line specifications for DEORE XT M8100 including a 55mm chain line, ensuring that the drivetrain is optimized for a greater variety of frame designs. Chainring options are 28, 30, 32, 34, 36T.

Enhancing ride performance and expanding gearing range, DEORE XT M8100 cassettes feature SHIMANO’s MICRO SPLINE freehub technology, allowing the use of 10-tooth cogs. The new design with its smaller splines also allows for an aluminum freehub body construction that isn’t damaged or gouged out by the cogs during use.

The new cassettes employ SHIMANO’s Beam Spider construction for weight reduction and improved power transfer utilizing a strategic application of aluminum and steel for a blend of weight savings, rigidity, and durability. It all adds up to a 510% gear ratio with the following gear steps: 10-12-14-16-18-21-24-28-33-39-45-51T. Meanwhile, the 10-45 Rhythm Step Cassette is designed for double or single front chainring setup, has a 450% gear ratio, and the following gear steps: 10-12-14-16-18-21-24-28-32-36-40-45T.

Shimano’s new DEORE XT wheels deliver value and reliability for riding on all types of terrain. For lighter trail riding, the WH-M8100-TL aluminum wheels feature straight pull spokes and 24mm rims. The WH-M8120 pairs an extra wide-flange hub with an offset rim to create a zero-dish wheel. With wider rims and J-bend spokes, the result is a wheel with good handling that’s easy to service. Both wheelsets are available in 27-inch and 29-inch wheel sizes.

The WH-M8100-TL lightweight tubeless wheels have 28 straight pull spokes, an inner rim with 24mm for use with tires up to 2.35, while the WH-M8120-TL are wider and stiffer, have zero dish, 28 J-bend spokes, and 30mm inner rim width for tires up to 2.6.

SHIMANO DEORE XT M8100 features two rear derailleurs that enhance shifting performance for both single and double front chainring setups. The derailleurs feature larger 13-tooth pulleys and include Shimano’s Shadow RD+ low profile technology.

Shifters and Levers

With ergonomics focused on comfort and control, the new DEORE XT RAPIDFIRE PLUS shift levers offer light operation force and better rider feedback. Shimano’s I-Spec EV lever design features greater flexibility in mounting while maintaining a clean cockpit. For double chainring systems, the lever simplifies front shifting with a lightweight and compact design that shifts up and down with a single mono lever.

Highlight features include MULTI RELEASE, which allows the release of two gears at a time, and 2-WAY RELEASE for instantaneous push and pull movements. They also have a textured rubber pad on the lever for enhanced grip, and 14mm of slide range and 20-degree rotation.


Employing SHIMANO’s mountain bike braking technology, DEORE XT M8100 increases brake rigidity for greater bike control and optimizes braking performance for different riding styles. A common SERVO-WAVE brake lever is paired with either a 2 or 4-piston caliper to deliver the right amount of power for a variety of terrain and riding styles.

Based on the SHIMANO XTR M9100 brake lever design, the new DEORE XT BL-M8100 brake levers feature a more inboard clamp position that creates an extra point of contact between the bar and the lever. This added bracing drastically increases efficiency and control over the bike while offering quick brake engagement. The new design minimizes impact on cockpit real estate, creating space between the clamp and support point for mounting other handlebar accessories.

The BL-M8100 Brake Levers utilize one XT brake lever for both 2-piston and 4-piston brake calipers, have quick brake engagement with shorter free stroke, and feature refined ergonomics featuring a taller and flatter lever blade face. Both the 2- and 4-piston brake calipers have an inboard banjo housing routing for clean setup.

Completing the puzzle is the RT-MT800 ICE-TECHNOLOGIES FREEZA Rotors, which boost heat dissipation, bringing FREEZA technology to the XT group for the first time. Options are 140mm, 160mm, 180mm, and 203mm.


The new M8100 pedals are more cross-country oriented, offering greater rider stability with wider edge-to-edge contact areas, while improving mud shedding through rounded contact points and off-set bindings.

Meanwhile the trail-style PD-M8120 have a wider contact area to improve stability with an expanded rearward shoe-pedal contact area. The 1mm cleat spacer creates a better interface with shoes of varying outsole design and lug height.

Finally, DEORE XT PD-M8040 continue to deliver flat pedal performance for trail riders now at a lower price. Offered in two sizes—small-medium (shoe size recommendation 36-44) or medium-large (shoe size recommendation 43-48) with 10 pins on either side and a slight concave design for comfort and efficiency. And best of all is the Reduced price. MSRP is $85.

To learn more head over to

**article from

bottom of page