Free wheel hubs (also called locking hubs) work by selectively connecting or disconnecting the front wheels from the front axles in a four-wheel drive (4WD) vehicle. This allows the vehicle to operate in two-wheel drive (2WD) with the front axle components disengaged, reducing wear and tear, improving fuel economy, and enhancing on-road handling.
Here's a breakdown of how they work:
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Disengaged (Free) Position: When the hubs are disengaged, the front wheels rotate freely without turning the front axle shafts, differential, and driveshaft. This reduces friction and rotating mass, leading to better fuel efficiency and reduced stress on the front drivetrain components when 4WD is not needed. The vehicle operates as a standard two-wheel drive.
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Engaged (Locked) Position: When the hubs are engaged, they physically connect the front wheels to the front axle shafts. This allows the engine's power to be transmitted to the front wheels, providing four-wheel drive capability.
Types of Free Wheel Hubs:
There are two main types of free wheel hubs:
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Manual Locking Hubs: These require the driver to physically get out of the vehicle and turn a dial or lever on each front wheel hub to engage or disengage them. They are typically more robust and reliable but require manual intervention.
- To engage: Turn the dial to the "Lock" or "Engage" position.
- To disengage: Turn the dial to the "Free" or "Unlock" position.
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Automatic Locking Hubs: These hubs automatically engage when the transfer case is shifted into 4WD. Some automatic hubs require a certain amount of wheel rotation before they fully engage. While convenient, they can sometimes be less reliable than manual hubs and might not engage in certain situations (e.g., deep snow or mud).
- Engagement: Occurs automatically when the transfer case is shifted into 4WD.
- Disengagement: Occurs automatically when the transfer case is shifted back into 2WD, often requiring a short reverse movement to fully disengage.
Benefits of Using Free Wheel Hubs:
- Improved Fuel Economy: By reducing the rotating mass of the front drivetrain when in 2WD.
- Reduced Wear and Tear: Less stress on the front axle components, extending their lifespan.
- Quieter Operation: Reduced noise and vibration from the front drivetrain in 2WD.
- Enhanced On-Road Handling: Elimination of potential binding or steering issues caused by a constantly rotating front axle.
In summary, free wheel hubs provide a way to selectively engage or disengage the front wheels from the front axle, offering improved efficiency and reduced wear when four-wheel drive is not necessary.
