Dictionary

7075-T6 Aluminum - 7075-T6 is the strongest and most expensive aluminum alloy that is used for structural and highly stressed components.

Anti-Squat Ratio - A formula that calculates the relation between the drive sprocket, rear tire contact patch, swinging arm pivot height, and the chain force lines. In order to determine the rear suspension’s characteristic to squatting under acceleration.

ACR - An Adjustable Compression Reservoir (ACR) is optional on special applications for UltraCross and UltraSport based on available space requirements. If you purchase UltraCross or UltraSport shocks without the ACR option these can be added or retrofitted at some future date to allow you to fine-tune the compression. Advantages: Works shocks are pressurized with nitrogen. Standard Works Performance shocks are gas-emulsion type, which means that the nitrogen is charged into the oil. The ACR unit is attached to the shock through a hose that transfers oil. The hose and ACR unit dissipate heat. Inside the ACR unit is a polyurethane bladder that separates the nitrogen from the oil. There are two advantages to this; One is the oil capacity of the shock is increased, which aids in cooling the shock fluid which increases the service life of the oil; and second is that the compression and rebound valving will stay consistent under the most severe of terrain.

Bladder - A closed-end, thick rubber, cylindrical shaped piece that contains the nitrogen gas in a rear shock. The bladder works like an extra cushion on HSC.

Bottoming - (also called bottoming out)-when a suspension component reaches the end of its travel under compression. Bottoming is the opposite of topping out.

Bumper - A taper shaped dense foam piece that fits on the shock shaft.

Bump Steer - The tendency of a vehicle to suddenly veer or swerve to one side when hitting a bump or dip in the road. The condition is caused by uneven toe changes that occur as a result of the steering linkage or rack not being parallel with the road surface. This causes the wheels to change toe unevenly as the suspension undergoes jounce and rebound.

Bushing - A bronze or plastic ring used as a load bearing surface in forks or shocks.

Camber - The angle between the plane of a wheel's circumference and a vertical line, measured in degrees and minutes. The tops of a car's wheels tilt inward when the camber is negative, outward when it is positive. As a general rule, most sport ATVs run 1-2 degrees of negative camber.

Clevis - A fork shaped piece of aluminum used as the bottom mount for most shocks.

Chassis - The frame, swing arm, suspension, and wheels of a motorcycle.

Chrome Silicon Steel - The primary alloy steel wire used for the manufacturing of coil springs commonly referred to as ASTM A 401. The material gets its name due to the fact that it has high levels of Chromium, Silicon as well as Carbon. In most applications and spring wire diameters the Tensile strength will exceed 235,000 Psi. Chrome Silicon Steel is ideal for cyclic compression spring applications and has a better fatigue life than Chrome Vanadium.

Clickers - The knobs or screws that control the LSC & LCR circuits of the forks or shock.

Coil Bind - Coil bind takes place whenever a spring is compressed and one or more of the spring's active coils contact another coil. The rate of the spring increases whenever a coil binds since the bound coil or coils are no longer active (this changes one of the three rate-determining factors). Handling is affected whenever a spring coil binds. If the spring is compressed to solid height (all coils touching) during suspension movement, the suspension will cease to work. You should check for evidence of coil bind by examining the finish between the active coils. If any coils have bound the finish between them will show contact marks that appear as though they were drawn with a lead pencil. Normally any spring that is binding should be replaced with a taller spring. Under extreme conditions, coil binding can cause a spring to unwind slightly. This can cause the mean diameter of the spring to increase and reduce the rate of the spring. The potential for coil bind is increased whenever short springs are used. Always match the spring to the job.

Coil Spring - Consist of a metal wire formed into a coil that can store energy when compressed and releases energy as the load is taken off.

Compression Damping - The damping circuit that absorbs the energy of compression forces on the damper. Compression damping assists the spring in resisting bumps and loads placed on the motorcycle, which is manifested in upward wheel motion. This kind of damping does not add spring rate, or make the bike carry a bigger load; it merely changes the rate at which the wheel is allowed to travel upward relative to the chassis.

Counter Steering - When the rider applies steering pressure in the opposite direction of the turn.

Damper - A set of forks and a rear shock are considered dampers. They slow the rate at which the suspension absorbs or releases energy. (See Damping).

Damper Assembly - The parts of a shock comprised of the clevis, shaft, bumper, piston, and shims.

Damper Rod - The large diameter aluminum tube in the lower leg of telescopic forks.

Damper Speed - The relative speed in which the moving end of a damper compresses (shortens) or rebounds (extends). Typically discussed as 2 elements which include 4 different cycles of the shock movement.

Damping - The process of absorbing the energy of impacts transmitted through the forks or rear shock on the compression stroke, and the process of absorbing the energy of the spring on the rebound stroke. Damping refers to the speed of the suspension component, not the velocity the bike is traveling over the ground. For further information click here.

Damping Circuits - There are normally four damping circuits which affect the damper's speed. There is both a low and high speed circuit for the compression and rebound strokes.

Front End Dive - This is what happens when the front forks compress quickly. It usually occurs when braking for turns.

Free Sag - The amount the bike settles under its own weight. This settling is about 6% - 10% of the total suspension travel. Too little bike sag can make the bike handle poorly and the ride harsh. Too much sag and you have less control over the bike, and you will lose travel of the suspension. The bike should not top out hard.

Hard Anodize - A dense wear-resistant anodic surface coating on Aluminum parts that has 50% buildup and 50% penetration into the material. In general, hard anodizing is applied following the military specification MIL-A-8625 Type III, Class 1 for non-dyed, or Class 2 for dyed applications.

Harshness - A word used to describe the rigid quality of the damping.

Head Shaking - A term that describes the high speed oscillation of the forks when braking for a bend at the end of a fast straight-away. Every motorcycle has a certain frequency band when it oscillates. This frequency can be tuned to a higher vehicle speed with a sacrifice in the bike’s ability to turn. Causes; Steep fork rate- not enough trail. Too stiff - compression damping. Not enough rebound damping. Front end lower than the back. Too soft front springs. Tighten steering head - put a little drag on it. Not enough sag

High Siding - A term that describes what happens when a bike falls to the outside of a turn.

Hopping - Wheel hopping is when the tire bounces up off the ground due to a reaction from a bump.

HSC - High Speed Compression damping is the damping circuit in the shock absorber or suspension fork that is tuned to provide suspension travel control at high speed over square edged bumps. Too low of HSC damping will cause excessive bottoming out in rough terrain. Too high of HSC damping will minimize suspension travel in rough terrain and cause loss of traction.

HSD - High-Speed Damping--damping to control fast vertical movements of suspension components caused by road characteristics such as square-edged bumps. High-Speed damping is independent of motorcycle speed.

HSR - High Speed Rebound damping is the opposite of High Speed Compression (HSC) damping.

Kicking - A word often used to describe both "Pogoing" and "Packing".

Leverage ratio - This is also known as a "motion ratio". This describes the path the shock goes through its travel in relationship to wheel travel. This is determined by the type of suspension and chassis geometry. In general a linkage system utilizes less space to operate and the shock absorber mounts on a lever, or series of levers between the arm and/or chassis. A no-link or direct shock link usually mounts the shock absorber between the arm or swingarm and the chassis.

Lock Out Blowoff Threshold - This is the force required to move the fork or rear shock when in Compression Lock-Out mode.

Low Siding - A term that describes what happens when a motorcycle falls to the inside of a turn.

LSC - Low Speed Compression damping circuit is affected most when riding through turns. Low Speed Compression damping is the damping circuit in the shock absorber or suspension fork that is tuned to provide suspension travel control at low damper speed conditions. Too low of LSC damping will cause the excessive travel use, brake dive and wallowing of the bike on small bump terrain. Too high of LSC damping will cause loss of traction on small bump terrain.

LSD - Low-Speed Damping- controls slow vertical suspension movements such as those caused by rolling bumps, wavy pavement, accelleration or in the case of fork springs, while making turns and during braking. (This is also independent of motorcycle speed.)

LSR - Low Speed Rebound damping circuit is the opposite of Low Speed Compression (LSC).

Magnesium - An excellent lightweight material that can be machined from billet or die-cast. A Magnesium die-cast lower leg is the best manufacturing method and material to satisfy the structural and precision machine requirements on a suspension fork. Magnesium has excellent vibration damping characteristics and is 34% lighter than aluminum and 77% lighter than steel.

Mid Turn Wobble - When the bike wobbles or weaves near the apex of a turn.

Nitrogen - An inert gas used to pressurize the Internal Floating Piston (IFP) or Bladder system or Reservoir in a gas charge shock damper. Note: Air is about 75% Nitrogen.

Oversteer - When a vehicle oversteers the rear tires are the first to slide and swing wide.

Packing - A term used to describe the ride characteristics of a rear shock or fork that has excessive , too slow, of a rebound setting. A damper with to slow of a rebound setting will stay compressed after hitting one bump and cannot rebound quickly enough to absorb the impact of the second or third bump, it further compresses (packs) further down on each successive bump. This can drastically change steering geometry if packing occurs on only one end of the motorcycle. The solution is to adjust the rebound to a faster setting.

Piggyback - See also Reservoir. This type of reservoir is available with compression only or compression and rebound adjustments. The shocks are a composite design constructed of a billet aluminum reservoir web and eye, with a durable steel pressure cylinder. Inside the cylinder they have a polyeurethane bag filled with nitrogen separated from the oil by a floating piston design. There is a sixteen position screw adjustment to control the flow of oil on the compression stroke. Another optional screw is added to the fork assembly, on the bottom of the shock assembly if you wish to fine-tune the rebound stroke.

Piston - A cylindrical shaped piece of steel with several ports arranged around the periphery so as to direct oil towards the face of shocks.

Piston Rod - A small diameter steel rod that fits into the upper legs of cartridge forks. It fastens to the fork cap on one end and holds the rebound piston and shims on the other end.

Piston Ring - A ring that fits around the piston and prevents oil from by-passing the piston and shims.

Pitch - A motion fore or aft, when the front end dives or when the rear end squats.

Pogoing - When the rear shock rebounds so quickly that the rear wheel leaves the ground.

Preload - Preload is the distance a spring is compressed from its free length as it's installed with the suspension fully extended. For example: A 4-inch long spring pre-loaded (compressed) 1-inch, applied to the fork and shock springs in order to bring the bike to the proper sag dimension. Note that if you have a 125 pound spring, with 1" of preload, it will take 125 pounds of additional pressure until the suspension moves at all. Adjusting preload to the proper sag dimension insures traction as wheel load gets light and drops into bumpy holed sections of terrain. CHANGING PRELOAD DOES NOT CHANGE SPRING RATE.

Preload Adjuster - A method of adjusting suspension components preload externally. On a shock these can be threaded pre-load, shims or spacers, or ramped as in the Works ARS System. On a fork spring kit, this is typically an internal spacer consisting of thin-walled aluminum or PVC tubing.

Race Sag - This term refers to number of millimeters that the forks or shock sag with the rider on the bike in full riding gear. This is essential to proper suspension tuning but is often overlooked or adjusted incorrectly.

Rake - The steering neck angle (not the fork angle) relative to vertical, which varies with changes in ride height. For example, the rake angle decreases when the front end compresses or is lowered. Changes in tire diameter can also influence rake by altering the ride height.

Rear End Squatting - Squatting occurs when you accelerate the motorcycle. The chain forces push down on the rear wheel. The resultant forces are transferred up the swinging arm into the main frame causing a lifting force which extends the front end causing a weight shift backwards.

Rebound Damping - The damping circuit that effects the stored energy release of the compressed spring in order to reduce the rebounding speed of the damper. Rebound Damping controls the extension speed of the fork or shock after it compresses over a bump--hence the term "rebound." After the wheel has hit a bump, the spring tries to force the suspension and wheel back toward the ground. The rebound damping controls the speed at which the wheel is allowed to extend.

Reservoir - A cylindrical shaped device that contains oil and nitrogen gas. This allows for a greater volume of oil to be used. More oil means better heat dissipation and less fade.

Re-Valving - A term used to describe a fine-tuning service for altering the compression and rebound shims in order to affect a certain damping characteristic that keeps the motorcycle’s wheels following the terrain in many riding situations

Ride Height - The amount the vehicle settles with the rider on the bike in a normal seated position. Rear suspension is approximately 30% - 33%, the front is around 25% - 30% of the total suspension travel. This is why a 300 lb rider would require a stiffer rate spring and more preload to maintain the same ride height as a 150 lb rider. Suspension spring pre-load adjustments, (raising or lowering the fork or lengthening or shortening the shock), are made to alter the chassis attitude of the motorcycle.

Roll - A motion where the motorcycle leans left or right from straight-up riding.

Sag - The amount (distance) the front or rear of the bike compresses A) under its own weight with no rider (Unladen Sag or Unsprung Weight), and B) fully loaded with a rider and all of his riding gear on board in the riding position. Sag can also affect steering geometry, as extra sag on the front end will decrease the effective steering head angle, quickening steering, while too little front sag will slow steering. However, too much front sag combined with too little rear sag could make the bike unstable.

Seal - A rubber or plastic cylindrical shaped piece that prevents oil from being lost from the damper.