Center of Gravity Height Calculator

Scope of the calculation

Estimate CG height from a controlled tilt and axle-weight change — reference values, sensor readings, and physical measurements should remain separately labeled.

This simplified relationship requires accurate scale, angle, wheelbase, and level-reference measurements — that condition defines when estimated cg height is comparable with another result.

Collecting compatible values

Wheelbase: Distance between axle centers — a compatible entry should use the same loaded condition for every weight and retain the scale ticket or rating source.

The Vehicle weight entry represents total scale weight — before calculating, use the same loaded condition for every weight and retain the scale ticket or rating source.

Front axle weight increase is defined here as front axle change after raising the rear axle — keeping that definition intact requires you to use the same loaded condition for every weight and retain the scale ticket or rating source.

For Vehicle tilt angle, use the quantity described as angle between level and raised measurement — in the vehicle record, keep the sign convention and reference plane consistent with the formula.

Collecting the data in practice

Capture the reference and test readings in the same session whenever the procedure permits — this workflow must also account for the fact that this simplified relationship requires accurate scale, angle, wheelbase, and level-reference measurements.

• Record Wheelbase as distance between axle centers — use the same loaded condition for every weight and retain the scale ticket or rating source.
• Record Vehicle weight as total scale weight — use the same loaded condition for every weight and retain the scale ticket or rating source.
• Record Front axle weight increase as front axle change after raising the rear axle — use the same loaded condition for every weight and retain the scale ticket or rating source.
• Record Vehicle tilt angle as angle between level and raised measurement — keep the sign convention and reference plane consistent with the formula.

Formula used on this page

In “CG height ≈ wheelbase × axle-load change ÷ total weight ÷ tangent(tilt angle),” the relationship answers the question stated above without adding an unstated correction factor.

No term beyond wheelbase, vehicle weight, front axle weight increase, and vehicle tilt angle is introduced in “CG height ≈ wheelbase × axle-load change ÷ total weight ÷ tangent(tilt angle).”

Interpreting the headline value

Estimated CG height answers “Estimate CG height from a controlled tilt and axle-weight change.” The additional display, Front-load change share, is a different view of the same entered measurements.

Suspension movement and tire deflection can introduce substantial error — when that condition changes, compare separate calculator runs instead of blending the inputs.

Because this simplified relationship requires accurate scale, angle, wheelbase, and level-reference measurements, a disagreement between estimated cg height and an outside reference should trigger a review of wheelbase and vehicle tilt angle.

A sensor or comparison value can narrow an investigation, but it cannot identify the failed part without the specified physical tests — for wheelbase, the page specifically expects distance between axle centers.

A related vehicle record may need to estimate a simplified turning radius from wheelbase and average steer angle, a relationship covered by the Vehicle Turning Radius.

Example using the displayed inputs

Using the loaded case, the recorded inputs are Wheelbase = 108 in, Vehicle weight = 3,500 lb, Front axle weight increase = 180 lb, and Vehicle tilt angle = 8 degrees.

For that data set, the calculator returns Estimated CG height = 39.52 in and Front-load change share = 5.14%.

If the next task is to estimate engine power from mass airflow using an entered empirical conversion, continue with the MAF Airflow Horsepower.

Questions about the formula and inputs