Coil bind
Encyclopedia
Coil bind is a style of setup used in various levels of NASCAR
racing
. Coil bind setups utilize very soft front springs and very stiff rear springs to control the pitch attitude of the body. This is in contrast with conventional setups which place the stiffer springs at the front of the car for superior mechanical grip
, that is grip via the vehicle suspension and tires. Coil bind uses aerodynamics
to produce grip.
As a car approaches the end of a straightaway, the downforce
generated by the body of the car should lower the sprung weight until the coil spring
s compress until they bind and the suspension can no longer travel (hence the name). The goal of coil bind is to keep the air dam (or splitter if applicable) at the front of the car as low to the ground as possible to create an area of low pressure under the car. The result is similar to ground effects
. Under braking, weight transfer
causes more weight to shift forward as the vehicle decelerates. This helps to maintain the low-pressure area below the car by keeping the front of the car low to the ground. While coil bind setups do yield faster lap times, the cars are more sensitive to turbulence
generated by nearby cars.
NASCAR
The National Association for Stock Car Auto Racing is a family-owned and -operated business venture that sanctions and governs multiple auto racing sports events. It was founded by Bill France Sr. in 1947–48. As of 2009, the CEO for the company is Brian France, grandson of the late Bill France Sr...
racing
Auto racing
Auto racing is a motorsport involving the racing of cars for competition. It is one of the world's most watched televised sports.-The beginning of racing:...
. Coil bind setups utilize very soft front springs and very stiff rear springs to control the pitch attitude of the body. This is in contrast with conventional setups which place the stiffer springs at the front of the car for superior mechanical grip
Traction (engineering)
Traction refers to the maximum frictional force that can be produced between surfaces without slipping.The units of traction are those of force, or if expressed as a coefficient of traction a ratio.-Traction:...
, that is grip via the vehicle suspension and tires. Coil bind uses aerodynamics
Automotive aerodynamics
Automotive aerodynamics is the study of the aerodynamics of road vehicles. The main concerns of automotive aerodynamics are reducing drag , reducing wind noise, minimizing noise emission, and preventing undesired lift forces and other causes of aerodynamic instability at high speeds...
to produce grip.
As a car approaches the end of a straightaway, the downforce
Downforce
Downforce is a downwards thrust created by the aerodynamic characteristics of a car. The purpose of downforce is to allow a car to travel faster through a corner by increasing the vertical force on the tires, thus creating more grip....
generated by the body of the car should lower the sprung weight until the coil spring
Coil spring
A Coil spring, also known as a helical spring, is a mechanical device, which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces...
s compress until they bind and the suspension can no longer travel (hence the name). The goal of coil bind is to keep the air dam (or splitter if applicable) at the front of the car as low to the ground as possible to create an area of low pressure under the car. The result is similar to ground effects
Ground effect in cars
Ground effect is term applied to a series of aerodynamic effects used in car design, which has been exploited to create downforce, particularly in racing cars. This has been the successor to the earlier dominant aerodynamic theory of streamlining...
. Under braking, weight transfer
Weight transfer
Weight transfer and load transfer are two expressions used somewhat confusingly to describe two distinct effects: the change in load borne by different wheels of even perfectly rigid vehicles during acceleration, and the change in center of mass location relative to the wheels because of...
causes more weight to shift forward as the vehicle decelerates. This helps to maintain the low-pressure area below the car by keeping the front of the car low to the ground. While coil bind setups do yield faster lap times, the cars are more sensitive to turbulence
Turbulence
In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...
generated by nearby cars.