Suspension Systems Questions and Answers

Answer: A

The wheel stays roughly perpendicular to the body, so it leans with the body in a corner and the outer tyre loses camber exactly when it is most loaded. A double wishbone can be arranged to gain camber instead. Struts are used on driven wheels universally. The order in which the effects act is what decides the outcome, so it is worth establishing first. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Answer: B

Choosing the lengths and inclinations of the two wishbones sets the camber curve, the roll centre and the scrub independently. It is why racing cars use it universally. The cost is space and complexity, which is why road cars often do not. Checking which component actually carries the load settles most questions of this kind at once. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. Reading the definition literally, rather than recalling a formula, is the reliable route through questions of this shape.

Answer: C

As the swing axle is compressed the wheel tucks under and the effective roll centre rises, lifting the body and increasing the camber change until the wheel tucks completely. Early Volkswagen and Mercedes designs suffered from it. Low pivot arrangements mitigated it. Tracing the requirement back to the physical constraint that produces it makes the answer follow. Most errors here come from carrying across a result from a neighbouring case where it does not hold.

Answer: D

A pure trailing arm pivots about an axis across the vehicle, so the wheel remains parallel to the body and leans with it in roll. Semi-trailing arms incline the axis to introduce camber and toe change deliberately. Each choice has consequences for handling. The shared behaviour explains why these belong together and the differences explain why both exist. Naming what changes and what stays the same is the reliable route through questions of this shape. Checking the units of each quantity catches a wrong formula before the arithmetic begins.

Answer: A

A multi-link uses four or five links, each controlling one degree of freedom, which allows the camber, toe and castor curves to be tuned almost independently. It is complex and expensive. It gives the best compromise of ride and handling available. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb.

Answer: B

An anti-roll bar is a torsion bar connecting the two sides, so it twists only when the wheels move differently and does nothing when both rise together. That is precisely why it can stiffen roll without stiffening the ride. Springs stiffen both. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Reading the definition literally, rather than recalling a formula, is the reliable route through questions of this shape.

Answer: C

Stiffening one end transfers more lateral load across that axle, which reduces its total grip and pushes the balance away from it. A stiffer front bar therefore adds understeer. It is the standard tuning tool for adjusting balance. Most errors here come from carrying across a result from a neighbouring case where it does not hold. The order in which the effects act is what decides the outcome, so it is worth establishing first. A single measurement chosen to respond to the one asymmetry beats several that respond to shared behaviour.

Answer: D

A rubber or microcellular bump stop takes up the last part of the travel progressively, protecting the damper and the body from a metallic impact. Coil binding a spring would destroy it. Modern bump stops act as a supplementary progressive spring. Naming what changes and what stays the same is the reliable route through questions of this shape. Checking which component actually carries the load settles most questions of this kind at once. Most errors here come from carrying a result across from a neighbouring case where it does not hold.

Answer: A

Microcellular urethane stops are shaped to engage early and stiffen progressively, allowing a soft main spring with adequate control at large deflections. They are a designed part of the spring rate curve, not merely an emergency stop. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Tracing the requirement back to the physical constraint that produces it makes the answer follow. A limit that survives making every external component ideal is an intrinsic one, and worth knowing for that reason.

Answer: B

Because the spring usually acts on the arm inboard of the wheel, the rate felt at the wheel is the spring rate multiplied by the square of the motion ratio. Only the wheel rate determines the ride frequency. Confusing the two is a common error. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.