Discover the All-New Shimano SLX and XT 12-Speed Drivetrains, Brakes and More 17

A group of scientists organized by Shimano, a global cycling and fishing component manufacturer, have discovered two new elements in the Valles Marineris on the planet Mars. The two new elements, known as Fixium (Fi) and Opportunia (Op) – although insignificant discoveries for the majority of scientists – are crucial to solving Shimano’s most recent issue with their XTR M9100 components producing an extra molecule of Unobtanium (Ub). The chemical compound of Difixium Opportunia reacts with the unwanted Unobtanium molecule to produce an available Shimano XTR M9100 group. What scientists didn’t realize was that this double displacement reaction also produced two other Shimano 12-speed groups. 

All jokes aside, let’s get to some facts. These two new groups, known as XT M8100 and SLX M7100, advance their current offerings from 11-speed to 12-speed and feature many of the same technologies introduced with the XTR M9100 group. Unlike XTR's laggy debut, XT and SLX components will be upon us soon.

UPDATE: While Shimano's new Micro Spline freehub standard was initially restricted to a small group of select wheel manufacturers, the company announced in September, 2019 that licensing will now open up to any manufacturer who requests it. We know of several companies who already have the product ready and available, just pending authorization to start selling, so hopefully this announcement will soon relegate this particular inconvenience to the history books.

Highlights

• 10-51 and 10-45 tooth 12-speed cassette offerings
• 1x and 2x direct-mount chainring options
• Stiffer brake lever design
• I-SpecEV for highly adjustable integrated cockpit setup
• Two and four-piston brake caliper options
• New resin brake pad compound for better modulation and durability
• Lighter shift lever action

The updated 12-speed drivetrains both get 10-51 tooth and 10-45 tooth cassette options that are centered around Shimano’s new MicroSpline freehub body. Along with a variety of single direct-mount chainring options, some double chainring options maximize the potential gear range. Just like XTR, these systems both feature Shimano’s Hyperglide+ technology for better chain retention and smooth shifting in both directions under load.

The updated brake lever design provides a stiffer, more positive brake lever feel and the highly adjustable I-SpecEV integrated brake lever, shifter, and dropper post configuration allows for complete cockpit customization. Along with the updated brake lever designs for maximum power transfer, XT and SLX brakes are available with two and four-piston brake caliper options to give riders the choice between maximizing power or lightweight performance.

Shimano XT M8100 Overview

What’s New with XT and SLX? How Does it Compare to XTR?

Shimano’s XT M8100 and SLX M7100 groups take all the same major updates in features and benefits from the flagship XTR M9100 12-speed components that were launched a year ago, but through some differences in manufacturing techniques, material choices, and a couple of omitted features Shimano trickled the technology down into two price-conscious packages. Every component, all the way down to the brake pads, gets an update for a comprehensive revamp across the board. The interchangeability across all three platforms will allow consumers to hand-pick each component to balance cost, features, weight savings, and durability.

Shimano’s new XT group is tied together with a classy, fast, polished black finish. The clean, smooth styling gives the group a cohesive look and feel throughout. In true XT fashion, the group has sex appeal, but also boasts durability and functionality with just a touch less of the bling-factor of XTR.

SLX, on the other hand, gets a little bit burlier look and feel. With the subtle yet tough gunmetal blue tone, SLX embodies the humble appearance of the workhorse functionality it is traditionally known for.

Cranks

At the heart of the group is the cranks, which get a bit of a cosmetic update for a more futuristic and sleek look on XT and a modern, tough feel in SLX. Following suit with many other component brands, Shimano will use the same direct-mount interface on their XT and SLX chainrings as XTR, allowing riders to choose between the various chainrings for personalization of gear ratios. Instead of using the chainring to differentiate chain lines, XT and SLX cranks are available with three different chain line options to accommodate different rear axle spacing and q-factors.

Both cranks continue to use the HollowTech II crank spindle interface and are a hollow forged two-piece alloy construction with the familiar left crank pinch bolts that have existed on Shimano cranks for a while now. The 1x XT crank adds 102-104g of weight when compared to XTR and the SLX cranks feature a slightly more cost-effective surface treatment than the pricier XT version.

Chainrings

Specifically designed to work in combination with the Hyperglide+ 12-speed chain, the tooth profile of the XT and SLX chainrings match that of the XTR ring, but rather than being crafted completely out of aluminum these more price-focused chainrings feature a steel tooth profile that is mated to an aluminum carrier. This makes both chainrings a bit heavier than their XTR cousin. Because the tooth profile is steel, Shimano can achieve ideal wear characteristics without the use of an extra special and super expensive surface treatment that is required on the full aluminum XTR chainring. The SLX version uses a slightly more inexpensive surface treatment on the steel tooth profile for just a narrowly cheaper retail price.

Single chainring options are available in XT from 28-tooth to 36-tooth, and SLX in 30-tooth to 34-tooth, complimenting the available 30-tooth to 38-tooth options in the XTR level. For those looking for double chainring options, the XT and SLX level rings will be available in 26/36-tooth combination. For riders potentially looking to swap back and forth from a single to a double chainring, SLX, XT, and XTR cranks use the same large chainring for single or double drivetrains. The outer chainring of the double setup is direct mount to the crank with the inner chainring bolted directly to the outer chainring.

Cassettes

Mega ranges are the name of the game these days, and the XT and SLX cassettes give riders the choice between a 510% range with the 10 to 51-tooth option or a 10 to 45-tooth option for those in search of more consistent gear steps or a 2x drivetrain. XT level cassettes use one less aluminum cog on the low end when compared to XTR, with the rest of the cogs being a steel construction. The SLX version gets just one aluminum cog and the rest steel. The beam spider design carries over from XTR to save overall weight, however, XT and SLX do not get any of the five titanium cogs that XTR features. Again, the XT cassette adds 94-113g of weight compared to XTR in an effort towards affordability, and SLX is an extra 52-65g heavier than XT.

Both cassettes maintain the same tooth profile and Hyperglide+ shifting characteristics, allowing riders to shift up and down the cassette under a pedaling load as touted with the launch of XTR last year.

Chains

The driving force behind Shimano’s Hyperglide+ drivetrain technology is the chain. With the introduction of Hyperglide+ and 12-speed XTR, Shimano attributed many of the updates in chain retention and shifting capabilities to the slightly longer inner chain plate allowing for less lateral play and more surface contact area. XT and SLX versions of the 12-speed chain feature the same longer inner plate design but naturally get slightly different surface treatments. Unlike the XTR M9100 chain, the XT and SLX chain don’t get the more robust hollow pin construction or Chromizing – the treatment Shimano uses to produce super strong chain pins – on the inner plates. Although the XT and SLX chains both come in at the same weight, the SLX chain only gets Shimano’s SilTec coating, which is designed to increase durability and performance on the inner plates whereas the XT version gets SilTec on both the inner and outer plates.

Rear Derailleurs

Following suit with XTR, XT and SLX get larger diameter 13-tooth pulley wheels for increased efficiency while maintaining the slim, rock-dodging, Shadow profile.

Both series get two different long-cage derailleurs, where the location of the upper pulley changes based on 1x or 2x drivetrain optimization. XT M8120 and SLX M7120 rear derailleurs feature a different upper pulley location in order to optimize 2x shifting performance. The 2x-compatible rear derailleurs can also be used for a 1x setup for those looking to possibly switch between 1x and 2x setups. Notably, the 1x-specific (M8100 and M7100) version is only compatible with the single chainring option. XT derailleurs weigh around 47-49g more than XTR, and SLX derailleurs weigh an additional 32g on top of that.

Front Derailleurs

For the first time ever, XT gets a sleek black front derailleur cage. SLX front derailleurs also get a slight facelift for cohesiveness across the line. Both lines use Shimano’s side-pull technology for more robust shifting between chainrings and are available in a variety of different mounting styles.

Rear Shifters 

Although Shimano will still offer a traditional band clamp for their shifters, the updated I-SpecEV integrated mounting system offers unrivaled shifter and dropper post lever adjustability. Similar to XTR, XT and SLX get 14mm of side to side adjustment, but just a touch less rotational adjustment. In order to achieve strength targets with the more inexpensive materials used on the XT and SLX shifter bodies, Shimano had to decrease the rotational adjustment from 45-degrees to 30-degrees, and Shimano argues the extra 15-degrees is unnecessary anyway.

At the XT level, Shimano maintains a small rubber pad on the thumb lever, but, unlike the XTR version, the rubber is not replaceable. For better ergonomics, the XT and SLX shifter both feature a slightly larger trigger lever than XTR, where the trigger is refined for weight savings. 

On the inside, the XT shifter keeps the same two-way release feature on the trigger as well as the multi-release function for the ability to drop down two gears with one shift. XT also gets the same instant release technology as XTR, so the downshift happens before the shifter trigger is returned. The SLX shifter gets a similar look and feel to XT, but loses the rubber pad, multi-release, and instant release functions.

Front Shifter

Employing the same technology from the latest XTR front shifter design, the XT and SLX front shifter are updated to feature Mono Lever technology. XT once again features a non-replaceable rubber pad on the thumb lever and SLX does not. With only one shift lever, the upshift is engaged by pushing the lever until the shifter locks in its second position. The downshift is then made by pushing the lever a second time to release the shifter OR by pulling the shift lever in a trigger action. The mono lever shifter design also doubles as an alternative lockout lever option for a suspension fork, such as FOX, with a simple push-to-unlock action. 

Brakes

With the introduction of the XT M8100 and SLX M7100 groups, both series get the same updated lever design featured on XTR M9100. The clamp band is moved inboard and more centered over the master cylinder, and a support perch is added to give the brake levers two points of contact with the handlebar. The updated design provides much stiffer and more positive action at the lever when braking. Along with the updated clamp design, both XT and SLX get the same updated taller and flatter lever blade design as XTR.

Rather than offering a Trail and Race brake lever set, both the XT and SLX levers feature Servo Wave technology for pairing with either a two or four-piston caliper. Both XT and SLX levers feature a tool-free reach adjustment, but those seeking the free-stroke adjustment will have to stick to the XT level. 

Although Shimano launched a four-piston XT brake model just last year, with the introduction of XT M8100 and SLX M7100, both the two and four-piston calipers get a modern facelift. The sleek design of the new calipers maintains the modern look and feel of the rest of the series with slim profiles, sleek in-board banjo routing, and compatibility with both the updated cooling fin-equipped and non-finned brake pads.

All brakes will come stock in the US aftermarket with finned metal compound brake pads, but finned and non-finned metal and resin pads are available for both the two and four-piston calipers.

With the launch of XTR, Shimano also introduced a new resin brake pad compound that is claimed to have a better ramp up in power, dead quiet performance, and an impressive 40% increase in durability. This technology will begin to replace the current resin compound for all models moving forward.

Rotors

For the first time, Freeza technology will trickle its way down to the XT level. Along with a modernized look and feel, the XT lever rotors will now feature the cooling technology of the extended alloy inner layer. Unlike the XTR version, it does not receive a special heat-dissipating paint application. SLX level rotors also get an update now featuring a two-piece design with an alloy carrier mated to the steel braking surface.

Hubs

With MicroSpline as a driving force behind the new XT and SLX groups, Shimano is coming to the table with a bunch of hub offerings.

The XT level hubs closely rival their XTR cousins in weight and will be available with both traditional j-bend or straight-pull hub flanges. SLX adds a bit of weight to the package and eliminates the straight pull option, but will still have a variety of axle options. Both XT and SLX rear hub models feature 100-points and 7-degrees of engagement, as well as a cup and cone bearing interface for serviceability and longevity.

Wheels

It has been a while since we have seen a new wheel system from Shimano at the XT level, but Shimano is yet again offering a complete wheelset in the M8100 series. They opted to ditch the proprietary spokes and rim interface we’re used to seeing in favor of very accessible and traditional 2.0/1.8/2.0 J-bend spoke design. 

This wheelset does, however, uses a special hub with extra wide hub flanges mated to an offset rim for a zero-dish build. The aluminum 28-hole rim features 30mm internal width for use with tries up to 2.6-inch width. The XT M8120 wheelset is offered in 27.5” and 29” wheel diameters with boost axle spacing and a Centerlock brake rotor interface only.

Pedals

Mimicking the cosmetic updates of the XTR trail pedal, XT trail pedals get increased platform surface area. The XT flat pedal also gets a bit of a cosmetic facelift and will be available in two different sizes to accommodate a wider range of riders.

Initial Impressions

With only a couple of days to thrash the new XT M8100 components on the radical trails of Bellingham, it was fun to put things to the test and see if any of Shimano’s claims fell short. Straight out of the box and onto the trail, shifting up the cassette into easier gears was noticeably smoother and the action at the shifter was much lighter when compared to the previous XT M8000 version. The downshift did seem to take a touch heavier push to engage, but after a couple of days on the trails it seemed to break in and lighten up a bit.

When blatantly trying to abuse the ability to shift the system under a massive pedaling load, the Hyperglide+ drivetrain system handled the abuse impressively. The smoothest shifts seemed to come with a normal amount of load on the pedals, and over the course of a few days riding the ability to shift in scenarios that normally would cause issues actually began to transform the thought process behind when it’s okay to shift. Another nit-picky issue that the new M8100 group eliminates over M8000 is the chain coming derailed when backpedaling in the lowest cog. The range of the 10 to 51-tooth cassette also came in handy on some the steep grinding road climbs of Bellingham.

Flipping to the downhills, the stiffness at the brake lever was a noticeable improvement over the previous XT M8000 design, especially when shutting it down for a blind stepdown that may have been a little much for our Ibis Ripley test bike. Chain retention did not seem to be an issue at all with the updated chain design and chainring tooth profile. When dumping gears in a mock gate-start scenario, the system also managed the abuse impressively.

The trickledown of a 510% range 12-speed drivetrain with Hyperglide+ technology from the XTR level brings modern Shimano precision to a working man's price point. Shimano delivers on claims of shiftability with the hammer down.

After a few days on the new XT M8100 group, it’s safe to say that Shimano has made some much-needed and significant strides in modernizing the XT component level. Although it’s not wireless and electronic, the ability to shift the system under load was an exciting characteristic.

Bryn Atkinson Rides the New 12-Speed SLX

Availability

Shimano knows they had some issues getting XTR M9100 out to the market. Learning from the mistakes they made, and putting in a huge company-wide effort for the launch of XT, Shimano set a hard date of June 14th for complete XT M8100 groups. Groups will be available exclusively for about two weeks, and individual parts are expected to be available soon after.

SLX M7100, on the other hand, does not have an exact date set. Shimano expects SLX to be available and shipping about a month after XT becomes available, around the middle of July.

Weight and Pricing Comparison

Shimano’s XT drivetrain is now ~89g heavier and $128 more than SRAM GX. Shimano SLX is ~137g lighter and $35 more than SRAM NX.

What’s The Bottom Line?

The new Shimano XT and SLX components feature some exciting updates and modernizations to two staple groups.

Although the introduction of these two new groups reinforces the existence of a yet another freehub standard (MicroSpline), XT M8100 and SLX M7100 solidfy Shimano’s presence in the 12-speed mountain bike drivetrain market. The trickledown of a 510% range 12-speed drivetrain with Hyperglide+ technology from the XTR level brings modern Shimano precision to a working man's price point. Shimano delivers on claims of shiftability with the hammer down.

The newly designed brake levers with highly adjustable I-SpecEV shifter/dropper post lever integration gives the brakes a nice, positive brake lever feel and very useable adjustments. Clean lines and cohesiveness across both the XT and SLX platforms show that Shimano put a lot of time into every detail of each component.

With a hard delivery date in sight for XT M8100 and SLX M7100 not far behind, Shimano fans can finally get the almost unobtainable 1x12-speed drivetrain in a more affordable package.

Visit mtb.shimano.com for more details.

About The Tester

Dylan Stucki - Age: 30 // Years Riding: 19 // Height: 6'5" (1.96m) // Weight: 180-pounds (81.6kg)

When he's not busy popping no-handed wheelies or shot-gunning beers, you're likely to find Dylan comfortably inside the top ten at Big Mountain Enduro races. Since he's a big guy and charges hard, he breaks a lot of stuff. With a broad riding and racing history, he's naturally a perceptive and particular rider who picks up on even the smallest details.

Photos by Shimano and Sterling Lorence