Modern Formula 1 car suspension connects different elements which all contribute to the overall performance on track. Suspension connects the engine power, downforce produced by aerodynamic package and tyres which all have to work in harmony to achieve competitive lap times.
Unlike road cars, comfort is irrelevant – springs and shock absorbers are very stiff to apsorb energy as soon as possible and enable aerodynamics to work more consistently. The springs absorb impact energy, shock absorbers dampen the movement and slow energy transfer prevent excessive oscillations. It’s like catching the ball rather than let it bounce. Also, there is an interesting comparison with human body – spring are bones as they carry the weight of the body, and shock absorbers are muscles that control the movement.
After active suspension was banned at the end of 1993. (when the parameters of the shock absorbers and springs were constantly changing, adapting to the surface of the track and corner type), suspension on the Formula 1 must be set up in garage and remain fixed on track. Modern cars have multi-link suspension front and rear that is similar to the system of double wishbone on some road cars. Such a system has an unequal length of the upper and lower wishbone in order to enable the best possible control of the angle at which the wheel is located in a corner.
As centrifugal force causes roll (lateral suspension movement), longer effective radius of the lower wishbone means that tyre tread (viewed from the front) is pointed out, which in corner gives more perpendicular position relative to the track and thus greater contact area and more grip.
Unlike road cars, the springs on Formula 1 car are no longer attached to the suspension arms, but are connected to the push rods and bell cranks which allow variable spring rates – springs are harder to compress as suspension load increases. Suspension components are made of carbon fibre for maximum strength and minimum weight, which is essential for ‘unsprung weight’ reduction (rotating components like wheels, brake discs, etc.) which has big impact on car’s performance.
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Suspension of modern Formula 1 car is multi adjustable on each wheel separately (except anti roll bar, which are adjustable for front and rear axles), but the most important are the settings of springs and shock absorbers. Also, it is possible to set the stiffness of the front and rear anti roll bars which influence how much weight is transfered from left to right corner of the car, camber angle (angle between vertical axis of the wheels and vercital axis of the car), toe (angle that each wheel makes with the longitudinal axis of the vehicle), ride height, maximum steering angle and so on.
Spring settings (spring rate or spring stiffness in N/mm) comes into play during lateral acceleration (corners), longitudinal acceleration (straight line acceleration or braking) or combination of two, which is very common. During acceleration, dynamic weight is transferred from one corner of the car to another (for example, in right hand corner weight transfers to the left, on braking weight transfers to the front and during acceleration from lef hand corner weight is transfered to the right rear corner of the car).
With softer springs more weight is transfered during acceleration and it’s possible to extract more grip from the tyres, with lower wear rates, but car will roll (lateral movement) and pitch (longitudinal movement) more which means less control and precision and more difficult for a driver to regain control after car loses stability. Also, car is not reacting so quickly during direction changes and ride height is less consistent which is not good for aerodynamic stability.
Shock absorbers (or dampers) are four way adjustable on each wheel because compression (bump or bound) and extension (rebound) can be set in the fast and slow working range. It is possible to specify a certain limit in the speed of movement of the spring (mm/s) to separate slow and fast movement. This enables shock absorbers to be set in one way when it comes to faster movement (bumps, kerbs et.), and in another way when it comes to slower suspension movements during cornering, acceleration and braking.
While spring rates determine how much dynamic weight is transfered, shock absorbers determine how quickly dynamic weight moves from one corner of the car to another. Shock absorbers control the springs movement – without them it car behavior would be erratic and uncontrollable.
When accelerating the rear shock absorbers are compressed and front are extended, while, for example, in a right hand corner left shocks are compressed and the rightare extended. Of course, when car is at corner entry or corner exit it accelerates and turns at the same time (combination of lateral and longitudinal loads) which leads to more complex combinations of damper compression and extension movements. Softer tuned shock absorbers allow the weight to transfer faster while stiffer setting means slower weight transfer.