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| Rack and Pinion Steering- This system eliminates the conventional steering linkage and steering box. A long rod, with tie rods on the ends, connects the two wheels. The rod is in a housing that lies parallel to the ground and has teeth on one side. A spur type gear is in mesh and connected to the steering wheel through the steering column. Steering wheel input moves that rod left or right steering both wheels directly. |
Ramp breakover angle- An angle formed from the contact area of the tires and the lowest part of the vehicle's midsection. A measurement of clearance.
Rate- The amount of weight it takes to deflect a spring. Expressed in pounds per inch. It takes 200 lbs to deflect a 200 lb/in spring one inch, 400 pounds for two inches and so on.
Rebound- the action of a spring returning to its natural ride height or preset 'memory" position.
Ring Gear- A circular gear in the axle housing that provides the axle gear ratio in combination with the pinion gear. A.k.a. "crown" gear.
Ride Steer- An undesirable symptom most often a problem in lifted 4x4s with track bars. As ride height changes, the transverse track bar changes the position of the axle in relation to the other and imparts a slight amount of steering input, which the driver must correct. This happens most often on lifted rigs with a great deal of angularity on the track rod.
Road- Any path over the ground designed for motor vehicle travel.
Roll Angle- The amount of body angle, or lean, the vehicle experiences on rough terrain.
Roll Steer- An undesirable symptom, most often seen in long travel coil spring rigs, whereby body roll changes the position of the axle and tends to steer the vehicle in a turn, requiring constant driver corrections.
Static Ride Height- the normal ride height of the vehicle at rest, with no dynamic forces working on it, such as cornering.
Scrag- A.k.a. "presetting." A method of setting the position "memory," or the permanent height or camber of a spring. After assembly, the spring is placed in a press and deflected a predetermined amount. This is usually past the normal deflection the spring will encounter in use.
Radius Arms - Fore and aft locating arms for multi-link suspensions. Most correctly, it refers to those suspensions that use a single fore and aft locating arm, than those that use two.
Section Width- The sidewall-to-sidewall width of the tire. Not to be confused with tread width.
Series Wound Motor- The motor has field windings that consist of copper wire wound over an iron core. A series wound motor is larger than a Permanent Magnet motor and has a much longer duty cycle (more resistant to heat). It draws more power than the Permanent Magnet type with nearly the same performance characteristics. These motors are most often used in the higher capacity, higher priced winches, or winches designed for commercial applications.
Shackle- Either a "D" or bow- shaped connector used for winching or recovery, or the pivoting link at one end of a leaf spring that allows the spring to "grow" longer or shorter as it flexes.
Shear Pin- A carefully designed pin in a PTO winch that is designed to break before something else does. Because PTO winches are driven by engines 100 times the power of an electric motor, the shear pin is calibrated to break before the winch or winch cable does. If you have a PTO winch, you should have a couple of extra shear pins just in case.
Shotpeening- Steel shot is sprayed at high pressure on the surfaces of a steel part to compress the surface of the steel and surface harden it. The technique is also used to surface harden parts such as connecting rods and leaf springs.
Semi-Float - An axle that supports the weight on the axle shaft as well as driving the wheel with it.
Slushbox- Slang for automatic transmission.
Snatch Block- A high capacity pulley used for winching.
Snatch Strap- A kinetic energy recovery strap.
Spool- The careful laying of the cable onto the drum, with the wraps wound tightly on the drum-tightly beside each other and tightly atop each other in succeeding layers. Also a solid carrier that connect the axles to the ring gear directly, with no differential.
Spool In- To bring cable in on the winch drum.
Spool Out- To let cable out off the winch drum.
Spotter- A person outside the vehicle who guides the driver over tricky obstacles.
RTI - Ramp travel index - A measurement of articulation and suspension travel calculated by driving one wheel up a ramp until one rear wheel lifts, measuring the distance up the ramp level with the hub center and dividing that mearsurement by the vehicle's wheelbase.
Stall Point- The point at which the winch stops under a load. This is often shortly past the unit's maximum line pull.
Stall Speed- The amount of slippage built into an automatic transmission torque converter rated by rpm. It's basically a measure of the torque multiplication of the converter. It can also be seen as, "Flash Stall," which is the engine rpm attained at a full throttle start from a dead stop.
Stock- As delivered from the O.E. manufacturer; unmodified.
Suspension Travel- The total up and down movement of the suspension with the axle on a level plane.
T-Case- Short for transfer case. Some parts of the world use the term, "transfer box."
Taco'ed- Bending some component into a "u" shape, or nearly so.
Tail Gunner- The captain of last vehicle in a group on a trail ride whose primary job is to make sure nobody gets left behind.
Tall Gearing- Numerically low gear ratios. Generally speaking, ratios from 2.50:1 to 3.54:1 are considered "high." See also High Gearing.
Taper- Some manufacturers taper the ends of each leaf of a leaf spring. This allows for a softer rate spring, as compared to a dimensionally similar untapered leaf, and reduced friction. Can also refer to bore wear in an engine. The upper part of a cylinder generally wears more than the lower and acquires a taper or funnel shape.
TBI- Throttle Body Injection. A fuel injection system that injects fuel into the airflow at the throttle butterflies atop the intake manifold.
Siping - Slits or cuts in the tread blocks that allow the blocks to move and grip. Sipes can be built into the tire by the manufacturer, or added later. Siping usually enhances the wet and icy performance of the tire.
Tie Rod- The steering rod that connects the two wheels together.
Threshold Braking- A technique of applying the maximum braking pressure possible, short of the tire lockup point.
Toe-In/Out- A steering geometry adjustment. Toe in is where the front edges of the tires point in toward each other. Toe out is the opposite.
Torque- Measured in pounds-feet (lbs-ft). Force times distance. One pound of weight on a one foot bar produces one pound-foot of force.
Torque Jacking- An undesirable symptom of lifted coil spring suspensions where the application of torque from tire grip is translated into a height increase in ride height.
Torsion Bar- A type of spring. One end is solidly attached to a chassis member and the other end is attached to one of the control arms. This converts the up and down movement of the suspension into twist on the torsion bar.
Toylet- A Toyota powered by a Chevy engine. A.k.a., "Chevota."
TPI- Tuned Port Injection. A GM high performance multiport fuel injection system.
Traction- The conversion of engine and drivetrain torque into motion.
Trail- Four-wheeler slang for an unimproved road.
Torque Converter- A fluid coupling/clutch used in automatic transmissions. It consists of three main parts, the impeller, which is driven by the engine, the turbine, which is connected directly to the transmission, and the stator, which lies between the two. The spinning impeller pushes the transmission fluid against the blades of the turbine, which forces it to spin in the same direction. The stator directs the flow of the oil.
Trailer Queen- Usually a show rig that travels by trailer. Can also be used for rigs that are trailered to and from four-wheeling spots. For some, this is a derisive term.
TTB- Twin Traction Bean. A Ford semi-independent front suspension for 4x4s used from 1980 to 1997.
U-Bolt- The u-shaped bolt used to attach the axle to a leaf spring.
U-Joint- Universal joint. A.k.a. Cardan joint.
Underwound Cable- Where the cable spools off the bottom of the winch drum.
Viscous Coupling- A device used either to lock a center differential or to transmit power. It consist of a number of plates in a sealed case full of silicone gel and an input and output shaft. Half the plates are attached to one shaft and the other half are connected to another, but they are alternating. When there is a difference in speed from one side, the silicone gel thickens and couples the unit together.
Void Ratio- The ratio of open areas in a tire tread versus the parts that actually contacts the ground.
Wheel travel- The total amount of up and down movement of the suspension as measured at the hub.
Wire Rope- The most correct term for the steel winch cable on a winch.
Wire Size- The coils of a coil spring are made from a bar of metal that is wound and tempered. Wire size refers to the diameter of this material.
Yield Point- The point where a material permanently deforms. It may not actually break but it's severely weakened.
