Derailleurs

Shimano's Tourney long cage rear derailleur incorporates advanced Shimano functions and styling that sets the standard for entry level components. - TY model comes with resin bracket and plate body for reduced weight - Zinc-plated adjustment screws for corrosion resistance - MegaRange compatible - Includes frame hanger - Maximum cog size: 34t - Total capacity: 43t

- Compatible with 6 and 7-speed SIS Index Shifting drivetrains - Includes BMX/track frame hanger

Elevating the shift, expanding the capable, the X01 Eagle derailleur features an updated cage architecture to provide better chain management than ever. The X01 Eagle rear derailleur works with the new 10-52T cassettes and is backward-compatible with 10-50T options, as well. - Updated cage provides better chain retention and more precise shifts - Backward-compatible design works with 10-50T and 10-52T cassettes

Shimano's Deore XT Rear Derailleur uses cold-forged construction and cutting edge technology to deliver crisp shifting, real-world reliability, and trademark precision. Plus-type derailleurs use a lever-actuated clutch spring to prevent chain slap, reduce noise while on the trail, and improve chain engagement when riding over rough terrain. Sealed pulley bearings keep things spinning smoothly, and wide plate construction prevents the derailleur from getting clogged with mud and debris.

Shimano's Deore XT Rear Derailleur uses cold-forged construction and cutting edge technology to deliver crisp shifting, real-world reliability, and trademark precision. Plus-type derailleurs use a lever-actuated clutch spring to prevent chain slap, reduce noise while on the trail, and improve chain engagement when riding over rough terrain. Sealed pulley bearings keep things spinning smoothly, and wide plate construction prevents the derailleur from getting clogged with mud and debris.

The Shimano Tourney TX800 front derailleur offers precise shifting with HYPERDRIVE technology for 3x8 speed drivetrains. - Action: TOP SWING - Angled clamp band design - Applicable Top-Mid tooth difference: 10T - Chain line: 47.5/50mm - Chain stay angle: 66-69 - Top gear teeth: 42T/48T - Total capacity: 20T

Enjoy quality and reliability with the Shimano Tourney 6/7-speed rear derailleur. It makes use of Shimano SIS, HyperGlide, and Double Servo technologies for smooth, accurate shifts. - Maximum cog size: 34t - Total capacity: 43t

Shimano Ultegra R8000 front derailleur. - Lighter front shifting operation - Link construction matches the force curve of the hand more naturally to reduce effort at the end of shifting - 100% perfect setting - New link construction allows for more flexible cable routing design - TL-FD68 and turning converter is not required in assembly - Easy and precise setting - Now possible to adjust cable tension on FD without specialized tools - Redesigned to fit wider gear pitch without sacrificing shifting performance - Shorter length of rear center (410mm) with O.L.D. 135mm - Model Number: FD-R8000-B - Series: Ultegra - Top Gear Teeth: 46-53T - Chain Stay Angle: 61-66 - Chain Line: 43.5 - Average Weight: 106 grams

- Prevents chain derailment when shifting to inner ring - Adjustable hose-type clamp fits 1-1/8" to 1-3/8" seat tubes

The Campagnolo Chorus front derailleur provides immediate, responsive upshifting with extreme precision. - Upper semi-rod not connected to the lower one for more effective, precise movement and no contact with travel limit - The derailleur stops transmission contact and friction to improve maximum cross-chaining situations - Designed to accommodate tires up to 32mm without the risk of contact with the derailleur - Double-position fixing of the cable allows for maximum compatibility with frames and tires - An optimized position for every engaged sprocket means limited risk of contact with the chain Specifications: - Derailleur Capacity: 16 - Front Der/Shifter Compatibility: Campy Centaur/Potenza/Chorus/Record/Super Record 2015+ - Max Ring (teeth): 52 - Front Derailleur Style: Traditional - Front Derailleur Cable Pull: Bottom Pull - Front Derailleur Clamp: Braze-on - Drivetrain Speeds: 12

The Shimano Dura-Ace RD-R9250 rear derailleur integrates the system charging port and a wireless connectivity unit all while delivering super fast, precise shifting worthy of any podium. A single cage length shifts cassettes from 11-28 to 11-34, offering exceptional versatility. - Ultra-fast rear Di2 shifting - Compact design includes an integrated wireless unit, charger, switch - Wider range capacity - Max. low sprocket: 34t - CFRP rear derailleur plate - LED status indicator - Battery indicator, pairing, adjust mode etc.

- 42-34-24t and 48-38-28t compatible, suitable for most Shimano 3x7/8sp drivetrains - Top swing with alloy base bracket/clamp - Dual pull design is convertible between top-pull and bottom-pull cable routing - Multi-clamp insert converts the 34.9mm clamp to fit 31.8mm and 28.6mm seat tubes - For standard 66-69 degree chainstay/seat tube angles - 143g

- 10/11 Speed compatible - MTB: Direct attachment (Shadow+) - 11T Min top Sprocket - 46T(1x10), 42T(2x11/2x10) : Max Low Sprocket

- Ergonomic Shifting Operation Without Stress - Shimano Synchronized Shift - Low Profile Rear Derailleur Design - Shimano Shadow Rd - Race Endurance For Less Damage In Crush - Maintains Compact And Smooth Appearance - Maximum Sprocket: 30T - Minimum Sprocket: 11T - Maximum Front Difference: 16T - Total Capacity: 35T

- Upper pulley has larger teeth for increased chain control

- 6061 Forged Alloy - Made to O.E.M. specifications - Correct hardness to reduce damage to frame upon impact

- Bulk packed and poly bagged - Speeds: 5/6/7 - Max Tooth: 48 - Wrap: 20 - Swing: Bottom

Shimano 105 7000-series components offer much of the same technology and functionality as their top-level 11-speed drivetrains at a more budget-friendly price point. The RD-R7000 rear derailleur provides stable shifting performance and wide-range compatibility in two different cage lengths. The Shadow RD design limits the amount the derailleur sticks out from the side of the bike, reducing the risk of it making contact with objects and bending. - Maximum cog size: 30t (SS) / 34t (GS) - Total capacity: 35t (SS) / 39t (GS) - Pulleys: 11t - Chain compatibility: HG-EV 11-speed/HG-X11 - Direct mount compatible

Shimano's Tiagra Front Derailleur (3x10-speed) is sleek, balanced and consistent. The Tiagra 4700 series provides serious entry-level riding performance with cascaded technology from the top shelf Dura Ace line. - Model Number: FD-4703 - Series: Tiagra - Cassette Compatibility: 10 - Top Gear Teeth: 50T - Maximum Capacity: 20T - Chain Stay Angle: 63-66 - Chain Line: 45 - Band Mount: 28.6mm / 31.8mm (w/AdapterS) 34.9mm

The Shimano Altus RD-M310 rear derailleur is a quality, durable replacement rear derailleur for 7 and 8-speed drivetrains. - 13t upper and 15t lower pulleys - Maximum cog size: 34t - Total capacity: 43t

SRAM’s Apex 1 drivetrain provides the gear range and the shifting simplicity to let you simply go where you want. The Apex 1 rear derailleur makes that gearing choice a reality with clean, crisp shifts, thanks to SRAM’s X-Horizon geometry and their Roller Bearing Clutch. - X-Horizon design reduces shift force, eliminates ghost shifting and chain slap - Compatible with 10-speed and 11-speed SRAM 1x road systems - With Cage Lock technology, wheel removal and installation are easier than ever - Equipped with Roller Bearing Clutch - Large upper pulley offset automatically adjusts chain gap - Weight: 314 grams - Outer Cage: Steel - Compatibility: 10-speed and 11-speed SRAM 1x road systems - Inner Cage: Steel - Cage Size: Long - Max Tooth: 42t - Pulleys: Sealed cartridge bearings - Pull: Exact Actuation

Features: - Smooth shifting and less cadence shock - Close step (10T) - SIDE SWING construction - Efficient cable routing - OPTISLICK cable - Stable performance on suspension bikes - Shifts properly while rear suspension handles rough trails and obstacles - Consistently quiet driving while rear suspension position changes - Custom plate design for single spike gear structure - Chain catcher - 2x10-speed

Shimano's Claris rear derailleur is a perfect replacement part or upgrade for 8-speed road drivetrains. HyperGlide technology results in smoother, faster shifting. - Maximum cog size: 32t (SS) / 34t (GS) - Total capacity: 37t (SS) / 43t (GS) - Pulleys: 11t - Chain compatibility: HG 8-speed

The heart of the connected cadre. The SRAM RED eTap AXS rear derailleur is AXS enabled for easy personalization and designed for both 1x and 2x systems. Advanced chain management keeps it silent and secure no matter the terrain. The derailleur also comes with faster pulleys, bearings, motors, and signals, improving speed in every way. - SRAM AXS-enabled for easy personalization - Orbit chain management technology keeps drivetrain quiet and secure - A single rear derailleur for all gearing combinations, including 1x and 2x - Improved motor and signal travel for faster shifting - Larger X-SYNC pulleys and ceramic bearings for increased durability and efficiency - Compatible with existing eTap batteries - Battery sold separately

This one takes all your trail dreams, from XC to enduro, all the way to eleven. SRAM's XX1 rear derailleur packs a massive amount of technology into its compact, lightweight body. It uses a “horizontal parallelogram” design that limits all movement to the horizontal axis, reducing the force it takes to shift. The Type 2 clutch is brilliant. This self-lubricating, one-way roller clutch controls your chain tension to eliminate chain slap and give you smooth, consistent shifts over any terrain. For quicker, smoother, more exact shifting, the large upper pulley's offset design maintains a consistent chain gap across all gears.

- Model Number: RD-R3000-GS - Series: SORA - Maximum Sprocket: 34T - Minimum Sprocket: 11T - Maximum Front Difference: 20T - Total Capacity: 43T

- Replacement plate for M7000-GS rear derailleur - Choose Inner or Outer

SRAM's X01 Rear Derailleur packs a massive amount of technology into its compact, lightweight body. This 11-speed gear changer uses a “horizontal parallelogram” design that limits all movement to the horizontal axis, reducing the force it takes to shift. The Type 2 clutch is brilliant. This self-lubricating, one-way roller clutch controls your chain tension to eliminate chain slap and give you smooth, consistent shifts over any terrain. For quicker, smoother, more exact shifting, the large upper pulley's offset design maintains a consistent chain gap across all gears.

Shimano's Alivio Rear Derailleur is built to withstand the rigors of off-road riding, with a lightweight aluminum body and low-friction pivots for incredibly easy and smooth shifting. And, the Alivio features 11-tooth pulleys, which alternate chain-link contact reducing wear and smoothing pedaling.

From top-tier XC racing to punishing endurance stages, Shimano defines the rear derailleur with their XTR Shadow Plus 11-speed model. The Shadow design is already well known and loved for its direct cable routing and low profile that greatly lessens the risk of snagging your cable on roots or tagging your derailleur on rocks. Shimano's Plus derailleur technology is a one-way clutch system that stabilizes the cage and your chain when ripping over rough terrain. Chain slap and noise is virtually eliminated and dropped chains are practically a thing of the past. And of course, it retains XTR's legendary smoothness, light action and super precise shifting. The long-cage design matches perfectly with XTR's new triple cranks and 11-speed cassette, offering Shimano's mega-wide gear range.

Ultegra RX brings Shimano's pioneering chain stabilizing technology to road cycling, delivering smooth and precise shifting over technical terrain. It expands road bike capabilities, inspiring confidence on any surface and drives the evolution of road cycling to include greater elements of adventure. No longer is the road bike narrowly defined. Shimano Ultegra RX broadens the notion of drop bar riding and emboldens cyclist to explore further. - Chain Stabilizer mechanism adopted from MTB design - Stabilizer ON/OFF switch - Compatible with current road dual control lever - Shadow RD technology - Direct mount compatible - Maximum cog size: 34t - Total capacity: 39t

Shimano Side Swing front derailleurs feature improved cable routing for smooth and efficient front shifting effort and increased clearance for larger tires and shorter chainstays. - Optimal front system for internal cable routing - Enhanced maneuverability with plus-sized tires - Increased shifting efficiency and light and smooth operation force - D, E, M type mounts are available - M type mount requires 34.9mm adapter

The 7-speed X-HORIZON rear derailleur makes shifting smooth and reliable no matter where you ride. Engineered to maintain consistent chain gap across all seven gears, X-HORIZON eliminates vertical movement for faster shifting, reduced shift force, and an end to ghost shifting. Our new, Type-3 roller bearing clutch features a smoother torque curve for a quieter, more consistent operation and feel. The 12-tooth X-SYNC pulley wheel holds the chain in place, reducing bounce and chain slap. Additionally, CAGE LOCK technology makes wheel removal and installation easier than ever. Paired with the X01 DH 7-speed shifter, X-HORIZON forms the backbone of X-ACTUATION technology—and that means completely smooth shifting action. - Updated design of the rear derailleur incorporates our proven X-HORIZON design and new Type-3 roller bearing clutch technology - 12-tooth X-SYNC pulley wheels - Large upper pulley offset automatically adjusts chain gap - Sealed cartridge bearings

Ultegra RX brings Shimano's pioneering chain stabilizing technology to road cycling, delivering smooth and precise shifting over technical terrain. It expands road bike capabilities, inspiring confidence on any surface and drives the evolution of road cycling to include greater elements of adventure. No longer is the road bike narrowly defined. Shimano Ultegra RX broadens the notion of drop bar riding and emboldens cyclist to explore further. - Chain Stabilizer mechanism adopted from MTB design - Stabilizer ON/OFF switch - Compatible with current road dual control lever - Shadow RD technology - Direct mount compatible - Maximum cog size: 34t - Total capacity: 39t

The SRAM Force 1 rear derailleur adopts all the technologies of SRAM 1x MTB to provide the fastest, quietest 1x shifting available. SRAM’s unique clutch system eliminates chain slack, providing for smoother, quieter, and more secure chain travel. - A dedicated 1x rear derailleur - EXACT ACTUATION for fast and accurate shifts using SRAM’s 1:1 actuation ratio (shifter cable travel: derailleur movement). - 10- and 11-speed compatible - X-SYNC pulley features a 12-tooth design that helps control the chain’s lateral movement - X-HORIZON “straight parallelogram” design limits all movement to the horizontal axis, which makes ghost shifting impossible while also reducing shift force - ROLLER BEARING CLUTCH’s one-way roller clutch controls chain tension for consistent shifting - Cage Lock technology makes for fast wheel changes or chain installation - Available in Short: 11-26 through 11-28 / Medium: 11-26 through 11-36 / Long 11-32 through 10-42 cage lengths Short Cage: Chain Wrap Capacity (teeth): 18 teeth Largest Cog: 28 Weight: 250 g Medium Cage: Chain Wrap Capacity (teeth): 26 teeth Largest Cog: 36 Weight: 262 g Long Cage: Chain Wrap Capacity (teeth): 32 teeth Largest Cog: 42 Weight: 271 g

The Box Two Prime 9 Rear Derailleur is very similar to the Box One version however, to be more wallet friendly, it offers a non adjustable Tri-Pack Clutch, bushing pulleys and some muted finishes. Box Two rear derailleurs are still optimized for 11-50t cassettes and offer durability and performance for the most demanding terrain, just at lower price!

- Adjustable chain stabilizer - Alloy cage and links - Max rear sprocket is 50t with 1X setup & 46t with 2X - 9 speed compatible

- 11-34T - Weight—354g

SRAM's X3 Rear Derailleur is ready for adventure. Its composite and steel construction is tough, while SRAM's 1:1 actuation ratio and direct cable routing provide quick, reliable shifts. This derailleur is compatible with 7- or 8-speed drivetrains.

Converts braze-on front derailleurs to clamp-on. Available in multiple clamp diameters.

SRAM's GX 2x10 rear derailleur provides incredible shifting speed and precision. Exact Actuation technology eliminates slop and shifting variation. Roller Bearing Clutch technology delivers maximum drivetrain stability—even through the most punishing terrain. And with Cage Lock technology, wheel removal and installation are easier than ever.

SRAM's X5 10-Speed Rear Derailleur provides precise, dependable shifting along with long-term durability. Its aluminum construction keeps the weight down, while SRAM's 1:1 actuation ratio and direct cable routing provide quick, reliable shifts.

SRAM's GX 1x11 X-Horizon rear derailleur is engineered for smooth, reliable shifting action—from the larger upper pulley offset to the 12-tooth X-Sync pulley wheels. By eliminating unwanted chain movement, this X-Horizon rear derailleur shifts faster, puts an end to ghost shifting, and reduces shift force and chain slap. And with Cage Lock technology, wheel removal and installation are easier than ever. • Long cage • X-Horizon design reduces shift force, ghost shifting, and chain slap • 12-tooth X-Sync pulley wheels • Large upper pulley offset automatically adjusts chain gap • Sealed cartridge bearings • Aluminum Cage

Find new ways to enjoy trekking and daily flat-handlebar riding with this reliable rear Shimano CUES RD-U6020 Shadow derailleur's seamless shifting and pedaling. Its low-profile design and chain stabilization give riders the confidence to choose rougher routes. Plus, e-bikers will benefit from reliable, long-lasting performance thanks to its eBike rated design. - Stable drivetrain performance on trails, gravel, and city streets - Shadow low-profile design protects rear derailleur from obstacles in a wide variety of riding scenes - Designed and tested to provide enduring e-biking performance - 11t upper and 13t lower pulley wheels - Compatible with LINKGLIDE AND HG 11-speed chains

The Shimano Altus 3x9 speed front derailleur offers light action and improved clearance for wide tires and mud. - 50mm chainline - Chrome-plated cage - 9-Speed

Leveraging the legendary history of SRAM shifting, the GX 2x11 rear derailleur provides incredible shifting speed and precision. X-Actuation technology eliminates slop and shifting variation while SRAM's roller bearing clutch technology delivers maximum drivetrain stability—even through the most punishing terrain. And with SRAM's Cage Lock, wheel removal and installation are easier than ever. • X-Actuation for precise and dependable 11-speed performance • Focused chassis design for all conditions and usage • 10-42-tooth wide range cassette compatible

Shimano's 105 Rear Derailleur delivers high-end function with upscale looks. With a body of light, durable cold-forged aluminum in Shimano's wide-pivot design with their light-action spring, rear shifting is practically effortless and always super smooth. The top pulley stays a uniform distance from each cassette cog ensuring that every shift resonates with the plunk of exact gear engagement.

M21 rear derailleurs are designed to work with 6- and 7-speed Shimano road and mountain shifters. Enjoy the wide variety of bikes you can get going again with M21 rear derailleurs. - Robust composite and steel construction - Compatible with Shimano 6- and 7-speed mountain and road systems - Long cage for double or triple cranksets and 32T max cassette cog - Includes frame hanger attachment for use with older frame designs

M-series rear derailleurs are designed to work with 7, 8, and 9-speed Shimano-compatible mountain and road shifters. Marvo LT rear derailleurs are built with precision rigid aluminum construction. Let these miracle workers get any bike rolling again. - Lightweight aluminum construction - Steel pulley cage for extra chain-rub durability - Compatible with Shimano 7, 8, and 9-speed mountain and road systems

Our fastest ever shifting across SHIMANO's widest ever DURA-ACE gear range, the RD-R9250 is capable of both race wins and personal bests. The DURA-ACE RD-R9250 integrates the system charging port and a wireless connectivity unit all while delivering super fast, precise shifting worth of any podium. A single cage length that is compatible with 28-34T low sprockets brings new versatility to the world's best road component group. FEATURES - Our fastest ever rear shifting, 58% faster than RD-R9150 - Compact design includes an integrated wireless unit, charger, and switch - Adjust mode, etc. - Wider range capacity (Max. low sprocket: 34T) - CFRP rear derailleur plate

• Converts direct mount front derailleurs to clamp on • Lightweight alloy • Fits 68/73mm and 100mm bottom brackets • 34.9mm clamp

Same specs as the K13-002 Pro Braze-on Chain Catcher but includes a Cadence Magnet required for SRM Power Meters, as well as other leading power meter brands. - CNC Machined 6061-T6 Aluminum - Fitment: All braze-on mounted front derailleurs* - Hardware: Includes all mounting hardware for Shimano, SRAM, and Campagnolo front derailleurs * Not compatible with Campy EPS * May not work with all third-party braze-on adapter clamps - Made in Boise, Idaho, USA - Lifetime Guarantee against material or manufacture defects. Damages due to abuse or crashing excluded.

The Shimano Tourney rear derailleur offers smooth shifting with SIS and HyperGlide technologies for 7-speed drivetrains. - Maximum cog size: 28t - Total capacity: 37t

The EX1 derailleur capitalizes on the robust build and precise shifting attributes of the X-HORIZON design, to create the world’s first derailleur specifically made for E-MTBs. Engineered to handle high-torque, low-cadence shifting across the 11-48 tooth E-Block cassette, the EX1 derailleur gives E-MTB riders clean, confident shifts, so they can spend more time enjoying the ride. - Proven SRAM X-HORIZON design that reduces shift force, ghost shifting and chain slap - 12-tooth X-SYNC pulley wheels - The EX1 derailleur is purpose built for E-MTB - Speeds: 1 x 8-speed - Weight: 289 grams - Color: Black - Outer Cage: Aluminum - Inner Cage: Aluminum - Bearings: Steel - Cage Size: Medium - Max Tooth: 48

It takes a degree of passion for the sport that can’t be faked to fully appreciate SRAM RED. It was created to blur the boundaries between machine and athlete. The SRAM RED rear derailleur was designed with Exact Actuation technology for precise, efficient shifting. Carbon fiber, titanium, and ceramic bearings complete the spec. The result adds to its legacy as the heart of the purest groupset for the pursuit of cycling excellence. - SRAM 11-speed compatible - WiFLi option - Carbon cages, carbon inner links, titanium hardware - Exact Actuation shifting provides fast and accurate shifts - Silent shifting with optimized AeroGlide pulleys, ceramic bearings - Spring-fixed barrel adjuster - Chain pulley cage adds precise chain management - Titanium pinch bolt keeps a low profile while minimizing weight - Speeds: 11 - Material: Carbon cages, Carbon inner links, Aero designed titanium hardware - Weight: 145 grams short cage), 165 grams (mid cage) - Compatibility: SRAM RED & Force Rear Shift-Brake levers, SRAM R2C Aero SL-1190 shifters, - SRAM R2C Aero SL-1150 shifters, SRAM 900 Aero brake levers, SRAM 500 Aero brake levers - Finish: Falcon grey & black anodized - Tech Highlights: AeroGlide Pulleys, Exact Actuation - Largest Cog (teeth): 28 (short cage) 32 (WiFli Medium Cage)

With an integrated chain stabilizer mechanism, the Shimano GRX derailleur provides a quieter experience with shifting security and precision on mixed terrain. For rides on smooth surfaces, the derailleur features and ON/OFF switch for the chain stabilizer. The RD-RX817 Di2 version offers the digital precision of Shimano electronic shifting, as well as synchronized shifting and is compatible with MTB cassettes with a max cog size of 42T. - Adjustable, gravel-tuned chain stabilizer prevents chain slapping and drops - Switch stabilizer ON/OFF to match the terrain - Silent and uninterrupted rear shifting on rough terrain - Compatible with current road Dual Control Levers - High cog: Max. 11T/Min. 11T - Low cog: Max. 42T/Min. 40T - Total capacity: 31T

Create a more active urban lifestyle with this durable Shimano CUES RD-U8000 Shadow+ rear derailleur's smooth and decisive shifting performance for 1x11-speed systems. Its low-profile design and chain stabilization give riders the confidence to choose rougher routes. Plus, the premium machine-finished aluminum textures showcase the integration of design and engineering. - Seamless shifting and pedaling performance that's made to last - Chain stabilizer reduces chain drop, slap and noise - Shadow+ low-profile design protects rear derailleur from obstacles in a wide variety of riding scenes - Stylish and polished aluminum finish with machine-cut textures - 13t pulley wheels - Compatible with LINKGLIDE AND HG 11-speed chains

Exceptional front shifting performance for large-wheel mountain bikes. Tackle trails with this Shimano CUES FD-U6000 front derailleur's smooth and quiet shifting. It is compatible with 2x11 and 2x10-speed drivetrains. - Smooth and quiet shifting on and off the trail - Provides and extra-wide range with front double - Offers wider tire clearance - Works with 48.8 - 51.8mm chainlines - 64-69 degree chainstay angle

SRAM's XX1 Ceramic Bearing Rear Derailleur Pulleys run on super-smooth, efficient ceramic bearings so your drivetrain rolls with ease. They are lighter than conventional pulleys and even come with SRAM's ceramic-bearing grease in an easy-to-use 10ml syringe.

From top-tier XC racing to punishing enduro stages, Shimano defines the rear derailleur with their XTR Shadow Plus 11-speed model. The Shadow design is already well known and loved for its direct cable routing and low profile that greatly lessens the risk of snagging your cable on roots or tagging your derailleur on rocks. Shimano's Plus derailleur technology is a one-way clutch system that stabilizes the cage and your chain when ripping over rough terrain. Chain slap and noise is virtually eliminated and dropped chains are practically a thing of the past. And of course, it retains XTR's legendary smoothness, light action and super precise shifting. The medium-cage design matches perfectly with XTR's double and single ring cranks and 11-speed cassette, offering a crisp, defined gear range.