Glossary of Terms

Off Roading Terminology


  • Air Locking Differential

    A locking differential that behaves like and open differential until it is locked manually for trail use.

  • Approach Angle

    The angle of clearance as a vehicle approaches an obstacle.

  • B

  • Break over Angle

    The angle between the vehicle's tires and the midsection clearance.

    Getting hung up on this center is called being "high-centered".

  • Buddy System

    Never go off roading alone.

    Getting stuck, lost or breaking something on your rig is a reality, having help with you is a common sense safety measure.

  • C

  • Clubs

    Clubs are great places to gain experience, meet people and experience new trails.

  • D

  • Departure Angle

    The angle to clearance as vehicle comes of an obstacle.

  • Differential

    The center section of an axle. The differential changes the direction of power from longitudinal to transverse.

  • E

  • Emergency Gear

    Things to take on every trip in to the outback, include tools, water, car condiments, food, signal mirror/light, flashlight, matches, rain gear, cash.

  • H

  • High Centered

    Getting the center of the vehicle caught on a high point between the vehicle's tires.

  • Hi-Lift Jack

    A heavy metal jack that allows for significantly more lifting action.

    Hi Lifts can also be used as a come-a-long device to winch a vehicle out of a difficult situation.

    This should be considered standard equipment for every serious off roader.

  • L

  • Limited Slip Differential

    A geared or clutched differential that allows some slip between the tires for cornering on hard surfaces.

  • Locker

    A differential that allows the tires to free wheel during corning, but locks up when traction is lost.

    Lockers have a characteristic clicking noise when freewheeling during corning.

  • Locking Hubs

    Locking hubs allow the front axle to free wheel when not needed for traction; saving wear and tear and improving fuel economy greatly.

    Locking hubs may be dash or manually operated.

  • Low Range

    A higher numerical gear ratio in the transfer case allowing finer control of speed and power in a four wheel drive vehicle.

  • M

  • Momentum

    Mass times Speed mathematically speaking.

    The inertia of a moving vehicle that allows a vehicle to traverse low traction or steep conditions or combination of low traction and steep conditions.

  • O

  • Open Differential

    The standard factory differential that transmits power to the tire with least traction.

    "Anybody stuck in Alabama knows one tire spins and the other does nothin', testifies Miss Mona Lisa Vito in "My Cousin Vinnie."

    If you are buying a new vehicle demand limited slip differentials, you will be glad you did.

  • R

  • Ramp Angle

    The angle between the vehicle's tires and the midsection clearance.

    Getting hung up on this center area is called being "high-centered"

  • Ruts

    Grooves in the trail from previous vehicles traversing during soft road bed conditions such as mud, sand or snow.

    Try to stay out of ruts by straddling to one side or driving with left side tires in the right side rut to improve clearance.

  • S

  • Spool

    A solid differential that does not allow for any difference in rotation of the vehicle's tires.

  • T

  • Transfer Case

    The center gear box that transmits power to the front and rear axles, most transfer cases have additional gear ratios to aid in rough conditions.

  • Tow Hook

    A frame or bumper mounted hook to attach tow equipment.

  • Tow Strap

    A long nylon strap used to pull another vehicle from a difficult situation, replaced heavy tow chains.

  • Trail Etiquette

    The unwritten rules of courtesy on the trail.

    Includes stopping to let uphill travel pass and helping anyone in need on the trail.

  • U

  • UFOs

    Unrestrained Flying Objects; these are things in your vehicle that are not strapped down safely.

    Minimize all unrestrained objects be strapping down boxes and putting small items in those boxes.

  • W

  • Winch

    A vehicle mounted cabling system that can pull a vehicle from a difficult situation.