SHIMANO XT M8100 JOCKEY WHEEL SET
The Performance Benchmark for 12-Speed MTB Drivetrains.
The Shimano Deore XT M8100 Jockey Wheel Set is the high-performance replacement for the pulleys in Shimano's premier 12-speed mountain bike groupset. In the world of modern "Hyperglide+" drivetrains, the jockey wheels play a critical role in managing the high chain tension of 1x12 systems and ensuring the incredibly fast, crisp shifting Shimano is known for. This "High-Grade" set is a significant step up from the Deore or SLX levels, offering a lighter construction and a smoother mechanical feel.
The standout feature of the M8100 set is the use of Sealed Precision Cartridge Bearings in both the upper and lower pulleys.While lower-tier sets use bushings that can develop "play" or friction over time, these sealed bearings provide a near-frictionless rotation and superior longevity, even when subjected to the dust and limestone grit common on Western Australian trails. The 13-tooth design is specifically optimized to reduce chain wrap friction and noise across the massive 10-51T cassette range.
Key Features
Dual Sealed Cartridge Bearings: Unlike the SLX model, both the Guide and Tension pulleys feature sealed bearings, ensuring the smoothest possible pedalling experience.
13-Tooth Large Profile: The larger 13T diameter reduces the angle of the chain as it passes through the derailleur cage, lowering drivetrain friction and noise.
Hyperglide+ Optimized: Specifically designed with tooth profiles that mirror the 12-speed chain’s inner and outer plates for instantaneous shifting under load.
High-Strength Composite: Constructed from a long-fiber reinforced resin that is incredibly stiff and resistant to the abrasive wear of mud and sand.
Precision "Float" (Guide Pulley): Features Shimano’s engineered lateral movement in the upper pulley to self-align the chain, compensating for minor cable stretch during long rides.
Technical Specifications
| Feature | Specification |
| Model Number | Y0GW98020 |
| Series | Deore XT M8100 |
| Speed Compatibility | 12-Speed MTB |
| Tooth Count | 13T / 13T |
| Bearings | Sealed Precision Bearings (Both Pulleys) |
| Weight | ~25g (Pair) |
Compatibility & Fitment Guide
While designed for the XT series, these are the preferred performance upgrade for many other 12-speed Shimano mountain bike derailleurs:
| Pulley Set Model | Series / Speed | Compatible Rear Derailleurs (RD) |
| XT M8100 | 12-Speed MTB | RD-M8100-SGS, RD-M8120-SGS |
| SLX Upgrade | 12-Speed MTB | Fits as a bearing upgrade for RD-M7100 |
| Deore Upgrade | 12-Speed MTB | Fits as a bearing upgrade for RD-M6100 |
| E-Bike Cues | 11/12-Speed | Fits RD-U8000 and RD-U8020 (Linkglide) |
✅ Why This IS For You
The Performance MTB Rider: If you want the quietest, smoothest 12-speed shifting available without the "race-day only" price tag of XTR.
SLX / Deore Owners: An excellent and affordable way to upgrade your current derailleur from bushings to high-quality sealed bearings.
Dust & Sand Warriors: Ideal for riders in sandy coastal areas or the Perth Hills where sealed bearings are essential to prevent the "grinding" noise of dirty bushings.
❌ Why This May NOT be for you
11-Speed Users: These 13-tooth pulleys are physically larger and have different tooth spacing than 11-speed versions; they will not index correctly on M8000 or M7000 systems.
Weight-At-All-Costs Racers: If every gram is a priority, the XTR M9100 set uses a slightly more skeletonized design and premium materials to save a few extra grams.
BFC Pro Tip
The M8100 pulleys are directional. Look for the small rotation arrow printed on the face of the pulley—it must point in the direction the chain moves when you pedal forward. Also, because 12-speed derailleurs use a very strong "clutch" (stabilizer), the pulley bolts are under more stress than on older bikes. When you reinstall them, use a torque wrench (2.5-5Nm) and a tiny dab of blue threadlocker. This prevents the bolts from vibrating loose during technical descents, which is a common cause of derailleur "explosions" on the trail!
