The Competitor Series Modular Spindle was rigorously designed be be both incredibly stiff, as well as strong enough to withstand the beating suspension components take in a performance environment.
What’s the difference between rigidity, and strength? And why is it important to understand the difference?
In the performance automotive aftermarket, suppliers typically advertise about how “strong” their parts are, but what does that really mean? There is a tremendous amount of marketing content claiming the use of certain materials that make the end product far better than the competition – and unfortunately too much of it is the result of poor engineering. It’s not hard at all for a person with access to an FEA program to punch in some numbers, whip out a pretty graph showing stress plots in fancy colors, all of which leads one to believe that the results are somehow meaningful. Sometimes, they are, but too often they are not and the average enthusiast won’t know the difference. Without really – honestly - understanding the forces applied to a vehicle suspension system in the real world, these plots are meaningless.
One very important distinction is the difference between rigidity, and strength. In layman’s terms, “rigidity” is the ability of a part or system to handle forces while allowing an acceptable amount of deflection. No matter how rigid the structure may be, it will always “flex,” it may imperceptible in many cases, but one goal of engineering design is to decide how much “flex” is acceptable. In order to determine how much flex is acceptable and to design around it, it is critical to understand exactly what the forces applied to the system are in all cases. We at Lateral Dynamics developed an exhaustive model to derive what the specific forces are at every single point, in all use cases – this data is the starting point for all of our product designs. In short, a “rigid” structure experiences a force, and when the force is removed, snaps back to the exact shape as before the force was applied, it doesn’t deform.
“Strength,” is a different aspect entirely. The strength of a component or system is basically the amount of force that the system can handle before it does deform – permanently. This may be in the form of a slight or large deformation, or a complete failure. Even if the part doesn’t deform or fail at some given load, it can still fail from “fatigue,” which is a condition where loads are repeatedly applied to the system, below the deformation limit, but over time add up and can result in failure. Think about a piece of thin sheet metal. You can bend it back and forth, and feel it getting weaker – until it finally snaps, this is a perfect example of a fatigue failure.
Rigidity, Ultimate Strength, and Fatigue are all critically important aspects for any vehicle suspension system, and even more so in performance applications.