Junior explains Coil Binding

I know a lot of you have asked me through our 3 Wide Life email about coil binding.  And we have actually done two Tech Zones on the subject.  But Dale Earnhardt, Jr. answered a question about it in my Iracing.com message board and I thought you might enjoy his take.  I think his explaination is one of the best I've heard and hopefully will allow you to better understand why racing teams do it.

Dale Jr. on Coil Binding

"Coil binding is still used in the COT somewhat, although its not the most common way to setup the front end. Bumpstops seem to be most popular.



"In the Nationwide and Truck series, coil binding is used extensively.


"Coil binding came about when people started to better understand the aero platform of racecars. Sealing off the valance provides much needed grip so running a soft spring would allow that to happen more consistently throughout a lap.


"The trick is to understand just how much you want a spring to coil bind. Too little coil binding at speed on new tires will create little or no coil binding as the speed falls off over the run. The car will become too loose. Too much coil binding can create ride quality problems and also over heat the right front tire and create too much PSI buildup.


"Teams use tire data and simulation programs to help them understand how much load is needed to optimize tire grip. This information will help the engineers calculate what type of spring will provide the best performance, as the spring will determine the load on the tire as it corners. Lets assume the data is suggesting that you run a spring that rates 1700 pounds at max load in the corner. Instead of actually running a stiff spring that will create that load, you can run a 350 or something in that range that will eventually coil bind and create 1700 pounds of load. Thus down the straights and entering and exiting the corner you have a lower car, creating more downforce." - Dale Earnhardt, Jr.