Thread: Spec V Suspension Information and Suspension Terminology

By: sickwithit

Wheel, Lug, and bolts

Bolt pattern: 4X114.3
Lugnuts: 12x1.25
Wheel Studs: 42mm front and 39mm rear.

Spec V 02-03
Weight: ~24 lbs
Wheel offset: 47mm

Spec V 04+
Weight: ?
Wheel offset: 47mm

Spring Rates

Stock Spring Rate Assumptions
123F/190R 2000-2003 GXE
123F/190R 2000-2003 XE
134F/190R 2000-2001 SE w/ 15” rims
134F/212R 2000-2001 SE w/ 16” rims
134F/212R 2002-2003 Se-r
134F/190R 2003 LE
154F/247R 2002+ Spec V

Aftermarket Spring Rate Assumptions
190F/240R Progress
150F/190R Sprint
170F/270R Tein S Tech
150F/250R Tein H Tech
180F/300R Nismo S-tune
???F/???R SpecV Sportline 4.6263 F1.8 R1.6
180F/300R SpecV Prokits 6362.140 F1.2 R1.0
142F/179R Non-SpecV Sportline 4.5563 F1.5 R1.4
???F/???R Non-SpecV Prokits 6355.140 F1.2 R1.0
168F/258R Tanabe NF210: F/R: 1.3"/1.1" - "Normal Feeling"
207F/314R Tanabe GF210: F/R: 1.3"/1.1" - "Grip Feeling"
174F/258R Tanabe DF210: F/R: 1.8"/1.8" - "Dress-Up Form"

Coilovers
390F/280R JIC FLT-A2
336F/336R Tein Basics
336F/280R Tein SS

Fender Rolling

You will likely need to roll your rear fenders if you are going to run a 225 tire with a 40 offset rim on a lowered car. Front clearance should be ok.


Sway Bar Info

Eibach Sway Bars
-Front and Rear
-25mm Front 19mm Rear

NISMO R-tune Thicker Rear Sway Bar
-Adjustable 25mm diameter sway bar, solid steel
-Includes firmer bushings with higher density rubber

OEM Spec V Sway Bars
-Front and Rear
-22mm front / 38mm rear
-Diameters measured with digital Calipers
-non adjustable
- The rear sway bar is contained in rear axle housing. The purpouse is to reduce body roll in cornering. The aftermarket Bolt on rear sway bar will just add in reducing said Body roll.

Stillen Sway Bars
-Front and Rear
-24mm front / 25mm rear
-rear is adjustable

Progress Rear Sway Bar
-19mm

Spec V OEM and Nismo Front Sway bar Rates

DIAMETER RATE
.866 (Stock)---------------271.7 LB
.906 (Nismo)---------------325.4 LB


General Suspension Terminology

A-arm: a wishbone shaped suspension member, usually with a pivot axis intersecting the end of each leg and multiple-axis pivot such as a ball joint at its apex

Acceleration: change in velocity of an object over time, either linear or rotational

Anti-squat: (anti-lift on front axle) rear suspension geometry that resists compression under acceleration; anti-squat increases traction on rwd cars, anti-lift decreases traction on fwd cars

Anti-dive: suspension geometry that resists pitch movements under braking, values about 50% are seldom used

Anti-roll bar: a torsion spring that resists independent motion of the wheels on opposite sides of the car, increases weight transfer at the end of the car at which it is mounted

Axle wrap, windup: often oscillatory rotation of a solid axle about its axis due to driving or braking torque, usually when located by a leaf spring

Balanced: in cornering, a condition in which the front and rear tires operate with equal slip angles

Body roll: tendency of a car to lean toward the outside of a turn

Bump steer: a steering geometry error in which the front wheels are turned on the steering axis by suspension movement

Bumpstop: elastic cushion that softens the impact when suspension travel reaches its limit

Bushing, suspension: rubber or plastic bearing in suspension joint that reduces transmission of vibration and road noise to chassis

Bushing compliance: deflection of suspension bushing resulting in inaccurate suspension geometry

Camber: inclination of a wheel outward with respect to the body

Camber correction, camber curve: change in camber angle of the wheel as a function of suspension travel or body roll

Caster: inclination of the steering axis in longitudinal plane

Center of gravity: center of mass

Center of mass: the point in a body or system of bodies at which the whole mass may be considered as concentrated

Coil bind: occurs when a coil spring is compressed fully so that each loop of wire is in contact with the loop on either side

Contact patch: the interface between the tire and the pavement

Control arm: a swinging suspension member to which the axle stub, or hub carrier in the case of a driven wheel, is rigidly attached

Characteristic frequency: the frequency at which a suspension will oscillate if left undamped, a function of wheel rate and sprung mass

Coefficient of friction: rate of increase of maximum friction force relative to a given increase in contact force; slope of traction/load curve

Critically damped: damping of a spring-mass system is at the minimum level that will prevent the system from overshooting its final position

Damper: a mechanism to control unwanted movement by converting mechanical energy to heat

Double wishbone (also double a-arm): a suspension configuration in which an upper and a lower a-arm control an upright hub carrier

Equilibrium: a condition in which all forces are balanced and no acceleration occurs, note that this is not necessarily static

Foamy bumpstop (also elastomer, long-travel bumpstop, supplemental spring): a bumpstop mode of a foamed polymer that compresses significantly before preventing further suspension travel, and can enter into normal movement of the suspension

Friction: a force that resists relative motion between two bodies in contact

Handling: a vehicles combination of traction, responsiveness, cornering balance and ride quality

Ideally damped: a sprung mass system is slightly undamped, so the system approaches its final static position quickly while maintaining acceptable limits for overshoot and oscillation

Independent suspension: suspension in which a disturbance of one wheel does not directly effect the transversely opposite wheel

Inertia: a property of matter by which it remain in rest or in uniform motion along a straight line or about fixed rotational axis unless acted upon by some external force

Initial understeer: reluctance of vehicle to begin rotating about its vertical axis on entrance to a turn

Kinetic energy: energy in an object due to speed

Lateral acceleration: rate of change in direction or a vehicles velocity vector on a horizontal plane

Leaf spring: a long, flat spring that acts in bending, usually used in groups

Linearity: mathematical concept; output of a system is proportional to an input, as with a constant-rate spring

Lowering: reducing the static height of a vehicle sprung mass

Lowering spring: a spring designed to accomplish lowering

MacPhearson strut: a telescopic member incorporating damping with the wheel rigidly attached at its lower end, such that the strut maintains the wheel in the camber direction; the upper end is fixed to the body and the lower end is located by linkages which pick up the lateral and longitudinal forces

Mass: the property of a body that is a measure of its inertia, that is commonly taken as a measure of the amount of material it contains

Model: a system of data and inferences, a physical representation, or a description or analogy used to help visualize or describe and entity

Motion ratio: the ratio between vertical motion of the wheel and compression of the spring, also between wheel rate and spring rate

Multi-link: similar to a double wishbone suspension, multiple linkages react to lateral and longitudinal forces

Newton’s second law of motion: the sum of the forces acting on a body is equal to the body’s mass (inertia) times its acceleration

Offset: distance between the plane where the wheel contacts the hub and the plane that defines the centerline of the wheel

Overdamped: damping of a spring-mass system is high, so that no oscillation occur in response to an input and the system does not overshoot its final static position; system is typically slow to respond to inputs

Oversteer: in cornering, a condition in which the rear tires operate at a high slip angle than the front tires

Panhard bar: method of lateral location of a solid axle in which a transverse member is attached to the axle at one end and to the chassis at the other end; roll center is defined by the point at which that panhard bar crosses the vehicle center line and can move vertically with respect to both the axle and the chassis

Passive steering: change is steer angle of rear wheels dude to suspension bushing deflection

Performance: a vehicles ability to meet operational requirements; with anything other than a race car, this involves much more than going fast

Performance spring: a spring designed to achieve optimum compliance with operational requirements; especially handling

Plow: severe understeer

Pilot load: a force transmitted through a single point; loosely, force transmitted through a single joint or pivot, as of a suspension

Polyurethane: a synthetic polymer that can be formulated for a wide range or hardness; recovers completely from high loads; remains flexible and shock resistant down to 0*F and increases in stiffness gradually at lower temperatures; highly resistant to abrasion and environmental degradation

Position-sensitive device: a device in which force between ends depends on position relative to each other, e.g. a spring

Potential energy: energy in an object due to position

Progressive spring: a spring having a rate that increase with increasing positive deflection

Race car: a vehicle meant to be optimized for maximum speed with adequate durability under race conditions

Recovery: behavior and required for a vehicle to return to its previous state after experiencing a disturbance

Recovery rate (of elastomer components): time required for a deformed elastomer to regain force/deflection characteristics it had prior to being deformed

Roll axis: a line intersecting the front and rear roll centers

Roll center: the point in the transverse vertical plane through any pair of wheel centers at which lateral forces may be applied to the sprung mass without producing suspension roll

Roll moment: torque about the roll axis caused by lateral acceleration, tending to roll the car body to the outside of a turn

Roll stiffness: restoring torque exerted by a vehicles suspension in resistance to body roll

Roll steer: change in steering angle in front and rear wheels due to suspension roll

Rolling resistance: negative longitudinal force resulting from energy losses due to deformation of a rolling tire

Rotational velocity: rational speed about a particular axis

Semi-trailing arm: control arm configuration in which the pivot axis is angled relative to the vehicles centerline

Shock absorber: a damper that operates in tension and compression but does not resist bending loads

Skid pad: a flat, circular area of pavement used to determine cornering characteristics of a vehicle

Slip angle: difference between orientation of the wheel plane and direction of wheel travel

Snap oversteer: oversteer that begins suddenly, especially if at a rate faster than the driver can correct; judgment depends on driver skill and experience

Solid axle: an axle configuration in which the wheel planes cannot move independently of one another

Speed-sensitive device: a device in which force between ends depends on their speed relative to each other, e.g. a damper

Spherical bearing: a low-speed baring in which load can be transmitted at a variable angle relative to the axis of rotation

Spring eye: the looped end of a leaf spring, used as a mounting pivot

Spring rate: the ratio of applied force to deflection of a spring, can be constant or variable

Center of sprung mass: center of mass of a vehicles sprung mass

Steering axis: the line defined by the pivot points of the steering suspension components; in most cased either ball-joint to ball-joint or ball-joint to upper strut bearing

Straight spring; a spring having a constant rate

Street car: a vehicle in which ultimate performance is compromised to achieve comfort, reliability, durability, low cost and low maintenance

Subframe: a frame that drivetrain and/or suspension parts are mounted to, which in turn is mounted to the vehicles body

Supplemental springs: long-travel, elastomer bumpstops that participate in normal suspension movement of the vehicle

Swing axle: form of independent suspension in which the wheel is rigidly mounted to a control arm which has a pivot axis parallel to the longitudinal axis of the vehicle

Swing axis jacking (also jacking): tendency of wheels to move vertically in response to lateral force, caused by an excessively high roll center in any suspension configuration

Tender spring: spring used to hold primary spring in position during full suspension droop; is completely compressed (in coil bind) during normal suspension movement

Terminal oversteer: tendency of vehicle to continue rotating about its vertical axis when exiting a turn

Toe: the difference in the transverse distances between the wheel planes of a pair of wheels, taken at the extreme rear and front points of the tire treads; when the distance at the rear is greater, the wheels are “toed-in” by this amount, and where smaller, the wheels are “toed-out”

Torque: twisting force, thought of a linear force acting on a lever arm

Torsion bar spring: a spring that is straight in shape and acts by resisting torque rather than linear forces

Track width: a lateral distance between the center of tire contact of a pair of wheels

Traction bar: used to control rotation of a live axle mounted on leaf springs; a rigid member with a snubber on the end bolts to the axle mount; snubber meets the forward spring eye under driving torque and prevents rotation but otherwise does not interfere with the action of the spring

Traction/load curve: their relationship between vertical load applied to a tire and the maximum friction force that can be generated

Transient: response of a vehicle to changing road surface or input

Turn-in: initial response of a vehicle when changing from a straight to a turning path of travel

Underdamped: damping of a spring-mass system is low, so that oscillations occur in response to an input and the system overshoots its final static position

Undesteer: in cornering, a condition in which the front tire operate at a higher slip angle than the rear tires

Unsprung mass: mass acted upon directly by the road surface, i.e., the wheel, tire, hub, spindle, brakes, and a portion of the suspension including the control arms, spring and damper

Valving: internal passages of a damping unit (i.e., strut carriage or shock absorber) responsible for its damping characteristics

Velocity: a quantity having both direction and speed

Watts linkage: method of lateral location of a solid axle in which a vertical member is mounted to the axle via a pivot, and each of its ends is connected to the chassis by a transverse pushrod; roll center is defined by the axle pivot and does not move laterally or vertically with respect to the axle

Weight: the effect that gravity has on mass, proportional to the strength of the gravitational field and the quantity of mass

Weight transfer: method by which a restoring torque (resistance to rotation) is generated when a vehicle is accelerated by application of force on a plane not containing its center of mass, i.e., the road surface

Weight transfer distribution: relative amount of lateral weight transfer at the front and rear of a vehicle when cornering

Wheel hop: periodic vertical oscillation of a wheel resulting in loss of traction

Wheel rate: the stiffness of a suspension as it acts at the contact patch, accounting for the effects of suspension geometry on the leverage of the spring

Work: expenditure of energy by applying a moving force over a distance: W=FxD

Me i got a question ... im looking at a set of springs that will lower the car 2 inch in front and rear so im wondering if the wheels still gonna clear the fenders without touching ( I got 215 ) and if they will touch if im getting 225 on 17 inch rims

thank you