RCB E2 SERIES BRAKING SYSTEM
RCB S1 SERIES BRAKING SYSTEM
UMA Racing CVT Pulley Roller (20×12) 12g set is a precision-engineered transmission tuning component designed to optimize the automatic shifting curve and acceleration response of high-performance scooters. Crafted from self-lubricating, heat-resistant composite material, these 12-gram rollers provide ultra-smooth movement along pulley channels while resisting thermal wear and flat-spotting under extreme high-RPM operation.
Key Features
Self-Lubricating Composite Sleeve: High-density polymer casing significantly lowers friction inside drive face channels, eliminating the need for sticky grease that attracts clutch dust and debris.
Super Heat & Wear Resistance: Formulated to withstand prolonged operating temperatures inside the CVT housing without deforming, cracking, or developing flat spots.
High-Precision Weight Calibration: Each 12.0g roller is manufactured to tight weight tolerances to ensure balanced centrifugal force against the ramp plate, preventing engine vibration.
Optimal Torque-to-Speed Ratio: The 12-gram mass offers a sweet spot for 155cc engines—boosting mid-range throttle punch without pushing engine RPM too high or sacrificing top-speed belt push.
Exact Vehicle Compatibility (20×12 Dimension Standard)
This 20mm × 12mm roller size is engineered for Yamaha 155cc platforms and standard CVT pulleys:
Yamaha NMAX Series: NMAX 155 V1 (2015–2019) / NMAX 155 V2 & Connected (2020+)
Yamaha Aerox / NVX Series: Aerox 155 / NVX 155 V1 (2016–2020) / Aerox 155 V2 Connected (2021+)
Yamaha Scooter Models: Nouvo LC 135, Ego LC, Ego Solariz, Ego Avantiz
Aftermarket Performance Pulleys: Fits UMA Racing V3 CVT Pulley Kits and aftermarket drive faces standardizing on 20×12 roller channels.
Technical Specifications
| Parameter | Specification Details |
| Brand | UMA Racing |
| Product Line | CVT Pulley Roller V3 Series |
| Dimensions | 20 mm (Outer Diameter) × 12 mm (Width) |
| Individual Roller Mass | 12.0 grams |
| Core Material | High-Density Brass Inner Sleeve |
| Outer Outer Sleeve | Self-Lubricating Ultra-High Polymer Plastic |
| Quantity per Pack | 6 Pieces (Full Set) |
Roller Weight Mechanics & CVT Behavior
In a Continuous Variable Transmission (CVT), roller weights use centrifugal force to push the movable drive face inward, forcing the belt outward into higher gear ratios:
Lighter Rollers (8g – 11g): Require higher engine RPM to push the pulley outward. Delivers rapid initial acceleration and instant throttle snap, but raises engine noise and may reduce top speed.
12g Rollers (Balanced Performance): Strikes a balance for daily commuting and light-stage tuning on 155cc engines—providing energetic throttle response off the line while maintaining smooth mid-range cruising RPMs.
Heavier Rollers (13g+): Shift early at lower RPMs for relaxed cruising and optimal fuel economy, but reduce low-speed acceleration pop.
CVT Maintenance Tip: Never install new roller weights into channels contaminated with old grease, belt dust, or road grit. Always wipe down the pulley channels completely dry before inserting new UMA self-lubricating rollers.
