RDLN High-Speed Gear Set (17/49) – GY6 50cc / 139QMB

Unlock Top-End Speed: RDLN 17/49 Performance Gear Set

Is your 50cc–100cc 139QMB engine revving at its limit without providing a higher top speed? The RDLN Performance Gear Set (17/49) is engineered to change your final drive ratio, allowing your engine to push the bike faster at lower RPMs. Depending on your current engine modifications and rider weight, this gear set can net an increase of up to 7+ MPH in top-end velocity.

Performance & Engineering

• Tall Gearing for Big Bore Kits: Transitioning to a 2.88 Final Drive Ratio (down from the stock 3.41–3.71) significantly reduces "over-revving" and is the essential final step for scooters equipped with 72cc, 80cc, or 100cc Big Bore Kits.
• Hardened Steel Construction: Precision-cut from high-carbon steel to withstand the increased torque of performance engines and prevent gear whine.
• Optimized Efficiency: By lowering cruising RPMs at high speeds, this gear set can improve fuel economy and reduce long-term engine wear.
• Balanced Acceleration: While taller gears slightly reduce off-the-line "snap," the 17/49 configuration provides the best balance of acceleration and high-speed cruising for the GY6 50cc 139QMA/B platform.

Comprehensive Fitment Guide

This gear set is compatible with 139QMB / 1P39QMB engine cases found on nearly all 50cc 4-stroke Chinese scooters:

Technical Specifications

• Teeth Count: 17 Tooth / 49 Tooth
• Final Drive Ratio: 2.88
• Weight: 540g
• Material: Forged & Hardened Steel
• Installation: Requires Hydraulic Press

Critical Installation Note: This is not a "drop-in" part. Installation requires a hydraulic press to remove the old gears from the secondary shaft and press the new RDLN gears on. Professional installation is highly recommended.

139QMB-based 50cc / 80cc engines with the following engine codes:

Don't see your engine listed? If the engine code includes "QM" or "FM", this product is compatible with your vehicle.

About RDLN: RDLN is a premier line of aftermarket performance upgrade systems and components for scooters. RDLN products are engineered to significantly improve the function, performance, and reliability of your vehicle with the ultimate goal being an optimal balance of price, power, and performance. RDLN’s extensive field-testing network ensures each product exceeds customer requirements and expectations every time. RDLN delivers full-throttle perf

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