Dynamics - Suspension Options

Goal of this page is to list possible options for the suspension and compare them.

Some links with more information:

Pushrod Suspension

How Pushrod Suspensions Work - Formula 1 Explained

Typically found in formula cars and other racecars
Components are kept internal, which improves the aerodynamics for open wheeled cars
(research still in progress)

Double wishbone

Description
- Shock absorbers and coil springs connect upper and lower control arms, with the steering knuckle and hub carrier on the lower control arm and the upper control arm attached to the frame
- Shock absorber has no structural functions
- Designed for frame-on-body vehicles
- Used mostly on the front axle
Pros
- More rigid than MacPherson strut suspension
- Optimal design of elasto-kinematic parameters; particularly for camber recovery
- Shock absorbers have no structural function; comfort can be improved because of hysterisis reduction
- Possibility of lowering the hood profile
Cons
- Heavier, greater unsprung weight
- More complicated, more linkages, bushings, connectors and rubber parts
- More expensive because of increased number of parts
- Takes up more space

MacPherson

Description
- Most commonly used in the front suspension of front-wheel drive cars, sometimes applied to rear axles
- Shock absorber, spring and steering knuckle form one element after mounting in the car
- One control arm, attached to the lower part of the steering knuckle, is responsible for the guidance
- Shock absorber rotates in relation to its axis when turning the steering wheel
- Designed for unibody vehicles
Pros
- Relatively inexpensive
- Relatively simple, compact design
- Reduced un-sprung weight (mass of suspension and wheels and other components directly connected to it) which makes the vehicle lighter
- Long and relatively thick shock absorber does not interfere with the creation of small cars
- Parallel wheel guidance is ensured despite the long suspension travel
- Take up less space than a double wishbone
Cons
- Lower performance in camber recovery (compared to double wishbone)
- Shock absorber piston rod deformation can increase friction and hysterisis
- When turning, by turning the entire column, the angle of inclination of the wheels relative to the ground slightly changes and there is unfavorable friction in the piston rod seat of the damper
- Tall → raise the center of gravity of the car

Trailing Arm

Description
- Attached to the wheel hub at one end, and extends forward to a pivot on the frame
- Usually found at the rear only
Pros
- High simplicity, lower cost
- Ease of assembly
- Reduced value of unsprung mass
- Suspension intrusion into the baggage compartment is minimal
Cons
- Transversal deformations of trailing arms caused by cornering forces have an oversteering effect
- No camber recovery
- High vibrational transmittance from the wheel because of bearing stiffness, due to the value of acting loads

Leading Arm