I've been absorbing myself in theory lately over different technical considerations as applied to suspension. While I'm looking to make some exotic changes to my own vehicle and gather knowledge pertaining to that change, I'm finding quite a bit of information that is pertanent to calibrating stock suspention, slightly modified (like lift kits) and right on up into complete custom designs. There is quite a bit of information available on calibrating and/or designing suspension targeted toward street, baja or rock climbing but very little on creating a well rounded vehicle which has adequite capabilites in all of the above at the expense of being exceptionally good at any one of them (hmm, sounds like a production sport utility, eh). If everyone is to get something out of this, I think a quick glossary of terms is in order and then we can play around with how they combine to excel in different areas. I want to clarify from the get go that I'm a complete novice and have never formally applied these elements on a full size vehicle so those of you who have, pipe up and add in the real world experience. So, from what I can gather: Spring - -A spring is an elastic device that resists movement in its direction of work. The force it exerts is proportional to the movement of one of its ends. Or to put this into a mathematical equation: Force = movement * spring constant. A high value for the spring constant makes for a stiff spring, and a low value makes for a soft spring. For progressive springs the spring constant will increase as the spring goes deeper into its travel, and for regressive springs it will decrease with travel. So math wise, springs aren't very complicated, but handling wise, they are. This is because the springs have to absorb the torques that are generated The problem is that they work in two dimensions: left to right and front to rear. Springs inhibit weight transfer, both front-to-rear and left-to-right: for the same cornering, acceleration or braking force a stiffer spring will compress less, resulting in less chassis movement and thus also less weight transfer, and a soft spring will compress a lot, resulting in a lot of weight transfer. Springs store and release energy. Unsprung / Sprung Weight- -Sprung weight is the weight supported by the springs. For example, the vehicle's body, frame, motor, and transmission would be sprung weight. Unsprung weight is the weight that is not carried by the springs, such as the tires, wheels and brake assemblies. Dampening (shocks)- - Damping is needed to absorb the energy associated with suspension travel and results in the generation of heat. In terms of energy, damping absorbs most of the energy the truck receives as it moves, unlike springs, who store the energy, and release it again. Dampers absorb all the excess energy, and allow the tires to stay in contact with the ground as much as possible. This also indicates that the damping should always be matched to the spring ratio: never run a very stiff spring with very soft damping or a very soft spring with very stiff damping. Damping that's a bit on the heavy side will make the truck more stable; it will slow down both the vehicle's pitch and roll motions, making it feel less twitchy. Note that damping only alters the speed at which the rolling and pitching motions occur, it does not alter their extent. So if you want your vehicle to roll less, adjust the springs, but not the dampers. Roll Center/ Instant Center - - A roll center is an imaginary point in space, look at it as the virtual hinge your car hinges around when its chassis rolls in a corner. It's as if the suspension components force the chassis to pivot around this point in space. The roll center is also the only point in space where a force could be applied to the chassis that wouldn't make it roll. The roll center will move when the suspension is compressed or lifted, that's why it's actually an instantaneous roll center. The roll centers/instant centers transfer the non-rolling forces to the road surface. The height of the roll centers and the instant center placement determines how much of the weight transfer at either end (front and rear)goes through the springs/shocks (rolling) and how much goes through the geometry(non-rolling). with low roll centers the springs and shocks transfer the majority of the weight. With high roll centers the location of the instant centers and any panhard bar take care of teh majority of the weight transfer. Center of Gravity - - Center Of Gravity is the spot within a vehicle where there is equal weight all around it. Roll Moment - - The vertical distance between the Center of Gravity and the Roll Center Anti Squat- - Anti-squat describes the angle of the rear hinge-pins relative to the horizontal plane. Its purpose is to make the truck squat less when accelerating. (Squatting is when the rear of the truck drops down when the truck accelerates) More anti-squat will give more 'driving traction': there will be more pressure on the rear tires as you accelerate, especially the first few meters. At the same time, it will give more on-power steering, because the truck isn't squatting much. The disadvantage is that the truck has an increased tendency to become unstable entering corners, especially in the rear. Reducing the anti-squat angle has the opposite effect: a lot less on power steering, and more rear traction when the truck isn't accelerating as much anymore. The truck will also be a lot more stable entering corners. It also affects the truck's ability to handle bumps: more anti-squat will cause the truck to bounce more when accelerating through bumps, but it will increase the truck's ability to absorb the bumps when coasting. Reducing the anti-squat does the opposite: it improves the truck's ability to soak up the bumps under power, but reduces it while coasting. Ride Height - - Proper ride height is very important, too low and the vehicle will bottom out a lot, too high and the risk of traction rolling will be unnecessarily big. Equal ride height front and rear is a good starting point. Raising or lowering ride height on one end of the truck changes the steering characteristics of the truck, the lowest end will have a slightly bigger percentage of the trucks static weight. But, more importantly, the roll center will also be lowered, making that particular end of the truck roll deeper when the truck corners, making it sit even lower and thus having more grip. Suspension Travel- - The amount of negative suspension travel (downtravel) a truck has can have a huge effect on its handling; it influences both the mount of roll and the amount of pitch the chassis will experience. An end with a lot of downtravel will be able to rise a lot, so chassis pitch will be more pronounced, which in turn will provide more weight transfer. For example: if the front end has a lot of downtravel, it will rise a lot during hard acceleration, transferring a lot of weight onto the rear axle. So the truck will have very little on-power steering, but a lot of rear traction. A lot of downtravel at both ends, combined with soft springs, can lead to excessive weight transfer: on-power understeer, and off-power oversteer. The cure is simple: either reduce downtravel, or use stiffer springs. Sway Bars- - Anti-roll bars are like 'sideways springs', they only work laterally. Here's how they work: if one side of the suspension is compressed, one end of the bar is lifted. The other end will also go up, pulling the other side of the suspension up also, basically giving more resistance to chassis roll. How far and how strongly the other side will be pulled up depends on the stiffness and the thickness of the bar used: a thin bar will flex a lot, so it won't pull the other side up very far, letting the chassis roll deeply into its suspension travel. Note that the bar only works when one side of the suspension is extended further than the other. Weight Transfer - - Newton's third law, force = mass * acceleration, implies that whenever the vehicle accelerates in any direction, additional forces occur. For example, when your car lands after having taken a jump, its downward velocity decreases rapidly. Basically, it stops falling down quite suddenly. The extra force associated with this equals the mass of the car times its acceleration. Transverse Weight Transfer- - Transverse weight transfer occurs because the driveshaft torque reacts between the frame mounted engine and the axle. The engine, which is a part of the sprung weight, produces the torque through the transmission. The rear axle has to resist that torque at the rear tire patch. Transverse weight adds cross weight under acceleration and removes cross weight durring deceleration. The manatude of teh transverse weight shift is a function of the instantanious engine torque and the roll stiffness. Lateral Weight Transfer - - Is the Weight Transfer from one side of the vehicle to the other. Longitudinal Weight Transfer- - Is the Weight Transfer from one end of the vehicle to the other. This is a good start, any feedback or corrections before we start throwing all this together?