There are some things about vehicles that an average person wouldn’t know, and the motion ratio is one of those things that could be puzzling. Getting to the nuts and bolts of how a vehicle runs helps you comprehend if everything is hunky dory. One way to find out is to determine the motion ratio and how it affects your suspension systems.

What is the Motion Ratio?

The motion ratio of a vehicle expresses how much leverage a wheel has on the damper and spring. This figure varies depending on the vehicle and may also change from the front to the rear.

Where the suspension attaches itself to the wheel can alter the motion ratio. The standard for most cars with independent suspensions is a suspension mounted to the spring near the wheel. Such a mounting will result in minimal leverage, whereas mounting the suspension farther from the wheel increases leverage.

How Do I Determine the Motion Ratio?

The purpose of finding a vehicle’s motion ratio is to have more of an understanding of how your spring is operating. You can find the motion ratio of any vehicle yourself by answering two simple questions and plugging those answers into an equation.

The first question you need to answer is: how far is the inner pivot point of the control arm from the center of the spring? The second question you need to answer is: how far is the same control arm’s pivot point from the outer ball joint? To solve for the motion ratio, take the numerical answer to the first question and divide it by the numerical answer to the second question.

You can find the wheel rate of the vehicle by taking the spring rate and multiplying it by the square root of your motion ratio. This number will tell the true story of how well your wheels are moving.

Why Should You Know Your Vehicle’s Motion Ratio?

The motion ratio explains how the suspension gradually stiffens as the car descends. Because stiffness is less important while lifting the car, the degree of relevance of the target at that precise moment lowers to zero. This will emphasize the compression function, which is more important than rebound. Ideally, a motion ratio that’s 1:1 is the goal for optimum comfort, although some may operate better with a different ratio.

How Do Motion Ratios Relate To Lift Kits?

There’s a lot of math and science behind it, but because of the physics behind motion ratio, a little suspension can go a long way. It all depends on how certain makes and models are set up, and it’s why certain lift kits will actually be thinner than the advertised lift height.

For example, the spacer for some three-inch lift kits will actually be much thinner than three inches to provide the advertised height. So, if you receive a kit and the part is thinner than expected, don’t worry. You’ll still get the desired height.

Learning how motion ratio affects suspension systems requires measuring and number crunching, but it allows you to learn more about your vehicle and how it operates. Let Supreme Suspensions® do the math for you and help you choose the best suspension kits available for your vehicle. Contact us today to get started!