Shimano has released details of its first 12-speed MTB groupset, the XTR M9100, featuring a 51-tooth cassette – one more than the biggest competing sprocket on the market.
The Japanese maker described the updated gruppo as “ground-breaking” with the choice of either a light 10-45t cassette for cross country, or a huge 10-51t option for Enduro-style riding.
A two or four-piston brake system also features in the 2018 component update, alongside a new hub design with ‘micro spline’ technology (see the ‘hub tech’ section below for more information).
The revisions include a redesigned brake and lever mount, allowing riders to position their controls – including an XTR dropper post lever – more freely to find the best position for comfort and rapid action.
The developments also shave over 150g in weight for XC riders and 90g for Enduro riders, while promising a more intuitive shifting set-up.
Shimano Europe product team leader, Bas Van Dooren, said: “Speed, focus and control were the words we lived by during the development phase.
“We’ve designed new XTR to enhance acceleration and speed by drastically cutting the loss of driving force with a re-designed drivetrain. We allow for precision focus with an intuitive handlebar set up and pin-point control comes with new brake solutions.
“New XTR is not an update of M9000, it’s a re-design from the ground up to find the best components for MTB racing for XC, Marathon and Enduro racing.”
Here’s a breakdown of the main changes:
Developments in the drivetrain started from the position of minimizing gear change steps to give riders the optimum rhythm and cadence between each gear and ultimately the most overall speed.
The result of this was the 51t sprocket, which comes after equal gear steps of 6t in the last three sprockets (10-12-14-16-18-21-24-28-33-39-45-51t) for an even cadence. XTR also introduces a 10-45t 12-speed cassette (10-12-14-16-18-21-24-28-32-36-40-45t) for faster or less steep MTB courses and less cadence shock. The 10-45t is for XC riders wanting small gear steps and the lightest set up, the 10-51t is for the trail rider to climb aggressive inclines.
Both cassettes use strikingly different metals for different sprockets to allow the best balance of weight and durability. The largest sprockets use aluminium, the middle use titanium and the smallest use steel.
A third cassette option comes with new XTR for riders specifically looking to create a stiffer and lighter wheel set. Essentially this option is based on the 10-51t cassette with the 51t sprocket removed to create an 11-speed cassette with 12-speed gear spacing. The benefit of this option is that it gives riders the chance to create a lighter bike and stiffer wheels which can be used with the same chain and shifter that the 12-speed set-up uses.
To fit the 12-speed set up Shimano restructured the freehub design with ‘micro spline’ technology to fit the cassette. This was accompanied by the introduction of SCYLENCE technology in Shimano’s rear hub, replacing the pawls with a ratchet system to reduce drag whilst coasting and create a virtually silent hub so you can focus more on the trail ahead. Front hubs are available in 100 or 110 mm spacing with a 15 mm thru-axle and rear hubs come in 142 or 148mm with a 12 mm thru-axle.
Alongside a dedicated 12-speed chain comes a 12-speed crankset. For XC 1×12-speed riders, there is a wide range of direct mount chainrings, saving up to 80g and available from 30T-38t. Enduro riders running 1×12-speed can add the XTR chain device to aid chain retention, and have the option of the FC-M9120 crankset with a wider Q-factor to fit particular frame dimensions.
Riders who want the biggest gear range and control in all types of terrain have the option of a 2×12-speed crankset in 38-28t that can be paired with the 10-45t cassette for the maximum gear range and close gear steps for long races with lots of climbing.
Three rear derailleurs are available at XTR level – long cage, short cage, and double chainring long cage. All have a sleek, aggressive, and angular anodized aluminium design. To aid shifting performance, the pulley wheels go from 11t at XTR M9000 to a larger 13t size to increase chain retention and minimize chain bounce.
The front derailleur is also available in three different styles depending on your frame. The D-type, E-type and M-type mounts all feature side swing technology for effortlessly smooth front shifting.
The shifter design is aimed to allow riders to instantly adapt to rapidly changing conditions with improved cockpit integration, shaving crucial tenths of seconds from each operation. That has been achieved through the creation of an I-SPEC EV design, which is the system by which handlebar controls can be mounted together. This gives 14 mm of lateral sliding range and 60 degrees of rotational positioning so riders can find their most ergonomic hand position and have clutter-free handlebars.
An dedicated dropper seat post lever can also be integrated, compatible with all common adjustable seat post types in the market including the PRO Koryak Dropper post.
Shifters also have a lighter operation force compared to XTR M9000.
Features like ‘Rapidfire Plus’, ‘2-Way Release’, and ‘Multi-Release’ carry over from the previous generation.
New for the M9100 shifters though is an 11-to-12-speed converter on the rear shifter for riders choosing the ‘11-speed’ wider flange hub set-up. For 2×12 riders the front left-hand shifter features an innovative new Mono Lever design with a simplified and intuitive operation, using just the one lever to shift up or shift down.
Building on what are already the standard to which all other brakes aspire to be, the design of XTR M9100 brake lever has changed with a repositioned clamp band and lever body. The clamp moves towards the middle of the lever body and the edge of the lever body is braced against the handlebar to create a stiffer brake with more direct contact feeling and improvement in control.
The two-piston option comes with a lighter-weight XC brake lever, with the option to adjust the reach of the lever arm. The four-piston brake set also features a dedicated brake lever but with a tool-free reach adjust function, free stroke adjust function, and Shimano’s Servo Wave technology to give rapid pad-to-rotor action. Both callipers are made from aluminium.
To match the redesigned calliper shape, the brake pad shape also changes. Riders choosing the four-piston calliper need the radiator finned pads, while the two-piston callipers fit the pads without fins.