Sla front suspension geometry program

Track width: inch. L FVSA length: inch. R FVSA length: inch. Left bump: inches. Roll angle: degrees. Right bump: inches. Showing suspension. There is a temptation to regard suspension as a topic ruled by something akin to "black magic", a subject so arcane as to require years of study and secret knowledge to fully comprehend. In actuality, understanding suspension is really very simple - the complexities arrive later when we start discussing weigh transfer and roll centres and whatnot.

At its most basic, the role of the suspension is to allow the wheels to conform as much as possible to road irregularities while isolating the body of the car - the sprung mass - from the effects of transiting these irregularities. This it does to varying degrees of effect; no suspension can ever completely isolate the sprung mass.

As a direct result, the sprung mass is subject to forces which can cause it to move as a unit relative to the unsprung mass. Much as the unsprung mass moves up and down in reaction to bumps, the sprung mass moves around in reaction to accelerations - things like turning, braking, and so on.

Of the two, roll is the most important from a cornering perspective, as that is the primary sprung mass chassis from now on movement during cornering. As the chassis rolls from zero roll at the entry phase of the corner, to maximum roll at midphase or near it , and then back out to zero roll at corner exit, a number of things happen:. The primary goal of the suspension, from a racing point of view, is to do all these things in such a manner as to maximize the amount of time that the tire spends in its "happy place" where it is making maximum grip.

A secondary goal is to perhaps induce behaviour conducive to balancing the car or affecting responsiveness - things like toe and roll steer come into play here.

But for the time being, we'll limit discussion to the primary goal. The first and most important consideration is that no suspension can "create" grip. The maximum amount of grip is produced when all four tires are equally loaded and in their "happy place" from a temperature, pressure, camber, and slip angle point of view. That's the best you can do. Suspension tuning can "unlock" potential grip, and a poorly tuned suspension can indeed lock away a lot of grip, but a happy tire is a happy tire.

Secondly, the factors that dictate what constitutes a "well-tuned" suspension are mostly related to the tire. A tire that is insensitive to camber angles is not going to require strict control over dynamic camber. A tire whose load curve falls off very slowly will be tolerant of changes in weight transfer, and so on. The factors remaining tend to be environmental, particularly how bumpy the race surface is and the nature of the course layout.

Thirdly, the basic design of the suspension we use assuming a production-based car as I do is largely determined by the original manufacturer - and they may have had goals in mind other than maximum lateral grip. For an OEM, packaging fitting the suspension in a small space ride quality both passenger comfort and NVH noise, vibration, harshness , and cost tend to be higher up the food chain than pure performance.

But whatever type of suspension the car is equipped with, that is likely the type of suspension you are going to race with. The rule book, the highly integrated nature of unibody construction, and economics makes it very difficult to switch from say a MacPhearson strut to a Double-A Arm. Accordingly, the first step in improving a suspension for race use is to figure out what the current one is doing.

This is so important, relatively easy, and reasonably cheap and yet almost nobody does it because it looks scary and hard. Instead, everybody wants to rush in to buying shiny parts and starting the Great Cut and Try Cycle. Measuring and modelling the OEM suspension saves enormous amounts of time, energy, and money, and can give you an initial setup that is most of the way there right out of the box. Time spent measuring is seldom wasted. With all this information, you can now plug values into the Dynamics Calculator and start to get an idea of what is going on.

Because the grip level of race tires is so much higher than street tires, usually the next step is to pick springs.

But there are upper limits on how stiff we can go with the springs, so we need a measure of "stiffness" to set the boundaries. That number is the natural frequency of the suspension - it is worked out for you in the Dynamics Calculator. This suspension is able to protect road shock causing the lower arm to twist the torsion bar.

When the wheels are no longer under stress, the arm returns to normal. The figure shows the simplified diagrams of the independent front suspensions using a coil, torsion bar and leaf spring.

Basically, the system is known as parallelogram type independent front suspension. It consists of an upper and lower link connected by stub axle carrier.

In general, the lower link is larger than the upper and they may not be parallel. This arrangement maintains the track width as the wheels rise and fall and so minimize tyre wear caused by the wheel scrubbing sideways. This type of suspension system is unusually for integral body construction because the loading points are widely spaced. The normal top link is replaced by a flexible, mounting and the telescopic damper acts as the kingpin.

This suspension system known as the Mac Pherson System has slight rolling action and absorbs shocks easily. Trailing arm independent front suspension maintains constant track and wheel attitude with a slight change in wheelbase and caster angle.

A coil spring is attached to the trailing arm which itself is attached to the shaft carrying the wheel hub. When the wheel moves up and down, it winds and unwinds the spring. A torsion bar has also been used in certain designs in place of the coil springs. In this type suspension system, the stub axle can move up and down as well as rotate in the frame members. Track, wheel attitude and wheelbase remain unchanged throughout the rise and fail of the wheel.

In the vertical guide suspension system, the kingpin is attached directly to the cross member of the frame. It can slide up and down, thus compressing and expanding springs. In the first type, the coil spring is located between the upper and lower control arms. The lower control arm has one point of attachment to the car frame. In the second type, the coil spring is located between the upper and lower control arms.

The lower control arms have two points to the attachment to the car frame. In the third type, the coil spring is between the upper control arm and spring tower or housing that is part of front end sheet metal work. Longitudinal leaf spring and coil spring rear end suspensions are widely used in modern vehicles. Transverse leaf spring rear end suspension is used in conjunction with the Hotchkiss drive, the leaf springs must be made strong and resilient enough to transmit the driving thrust and torque to resist sideways, in addition, to hold the spring weight of the body.

The spring weight is kept as less as possible, in order to improve the side of the vehicle. Because the springs do not generally support the wheels, rims, tyres, brakes and rear axles, the weight of these parts is called the spring weight. The spring is clamped the rear-axle housing by U-bolts, its every end is pivoted to the frame, by means of eyes formed in the ends of the longest leaf.

One end of the long leaf is secured to the front hanger by a bolt and the other end to the rear hanger by spring shackles. Instructions First, let's start by looking at the suspension movement and the tools available to make your life easier: The chassis movement control allows you to raise and lower the chassis and also rotate the chassis by moving the mouse or your finger side to side.

The chassis always returns to the static position when releasing the mouse. As you move the chassis notice the variations are displayed within the calculator. If you are logged in you will also notice the roll center and instant centers are also displayed. If the chassis rotation becomes an annoyance you can disable the rotation function by pressing this button.

When rotation is disabled the button is displayed with a strike through. Click here to test the toggle rotation function. Moving this icon within each of the the tires up and down allows you to test movement of each wheel individually to simulate travelling of uneven ground. The wheels always return to the static position when releasing the mouse.

If ever you see the explosion it means that a clash or breakage would occur. This could be the chassis hitting the ground, a control arm hitting a wheel or a control arm being stretched to the point it would break. You can use this as a gauge to work out the extents of the suspension travel.

You can use the plus and minus buttons to zoom in and out of the drawing when analyzing and when editing the model. You can pan the drawing by clicking and dragging but if panning becomes an annoyance you can disable it by pressing this button. When panning is disabled the button is displayed with a strike through.