GEARBOX RMI 85 PP R20 P112 B5 i=28mm, o=35mm

Gearbox RMI 85 PP R20 P112 B5 I28mm O35mm | Genuine | Muir AU

The Muir Gearbox RMI 85 PP R20 P112 B5 I28mm O35mm is a genuine factory replacement designed for HR4000 Thor horizontal windlasses. Precision-engineered to exact OEM specifications, this unit transmits motor torque to the windlass drive system, delivering the controlled speed reduction and heavy torque output needed for safe, reliable anchor handling on serious offshore vessels.

Built for Marine Conditions

The unit features the proven RMI 85 PP R20 design with P112 B5 flange mounting, a 28mm input shaft, and 35mm output shaft — engineered for perfect mechanical compatibility with the HR4000 Thor windlass. Manufactured to Muir's strict quality standards, it withstands the rigors of constant load cycles and harsh marine environments, ensuring long-lasting performance season after season.

Key Features

• Genuine Muir replacement for HR4000 Thor windlasses
• RMI 85 PP R20 specification with P112 B5 flange
• 28mm input shaft, 35mm output shaft
• Precision-engineered for exact OEM compatibility
• Reliable torque transmission under heavy load
• Direct fit — no modifications required

Why Choose Genuine Muir Parts?

Choosing the authentic Gearbox RMI ensures perfect alignment, optimal torque transfer, and long-term reliability. Aftermarket alternatives often use inferior gears and bearings that wear quickly, generate excessive noise, or fail under load — risking damage to your windlass and unsafe anchoring. Trust genuine Muir parts for dependable performance and full warranty support.

Order your replacement gearbox today from Muir Australia — trusted marine engineering since 1968.