Cross Weight Calculator

Reviewed By: Patrick Myers (BSME)

Enter your four corner weights (LF, RF, LR, and RR) into the Cross Weight Calculator. The calculator will evaluate the cross weight percentage.

Units:

All weights use the selected unit.

4-Corner

Target Cross

What‑If

Enter your four corner weights (scale readings). Results update on Calculate.

Left‑Front (LF)

Right‑Front (RF)

Left‑Rear (LR)

Right‑Rear (RR)

Total Weight

Cross Weight (%)

Left Side (%)

Front (%)

Right Side (%)

Rear (%)

Diagonal RF+LR

Diagonal LF+RR

Summary will appear after Calculate.

Cross Weight Formula

The following formula is used to calculate the Cross Weight.

CW = (LR + RF) / TW * 100

Variables:

CW is the Cross Weight (%)
LF is the left-front weight (lb or kg)
RF is the right-front weight (lb or kg)
LR is the left-rear weight (lb or kg)
RR is the right-rear weight (lb or kg)
TW is the total vehicle weight (same unit); if using corner weights, TW = LF + RF + LR + RR

To calculate the cross weight, sum the left-rear and right-front weights, divide by the total vehicle weight, then multiply by 100.

How to Calculate Cross Weight?

The following two example problems outline the steps and information needed to calculate the Cross Weight.

Example Problem #1

First, determine the left-rear weight (lbs).
- The left-rear weight (lbs) is measured to be: 500.
Next, determine the right-front weight (lbs).
- The right-front weight (lbs) is measured to be: 600.
Next, determine the total car weight (lbs).
- The total car weight (lbs) is found to be: 2000.
Finally, calculate the Cross Weight using the formula above:

CW = (LR + RF) / TW * 100

The values provided above are inserted into the equation below and computed.

CW = (500 + 600) / 2000 * 100 = 55.00 (%)

Example Problem #2

The variables required for this problem are provided below:

left-rear weight (lbs) = 500

right-front weight (lbs) = 400

total car weight (lbs) = 3000

Test your knowledge and check your answer with the calculator.

CW = (LR + RF) / TW * 100 = (%)

Follow-Up Calculations

On a 3,000 lb stock car showing 52% cross, the LF/RR diagonal carries 1,560 lb while the opposite diagonal carries 1,440 lb, so a 120 lb diagonal imbalance can show up as a pull or inconsistent turn-in. If you want to see how a spring and suspension geometry change that load actually behaves at the tire, the effective spring rate at the wheel tells you how much force the suspension really delivers after motion ratio is applied.

If your cross weight is 51.5% and you're trying to correct a 45 lb imbalance with preload, the same turn of the adjuster won't move every corner equally because suspension leverage changes the result. The spring-to-wheel leverage ratio shows how far the wheel moves for a given spring movement, which is why a small preload change on one corner can shift the cross much more than expected.

At 52% cross on a 3,200 lb car, the LF/RR diagonal is carrying 1,664 lb of static load, so those tires can usually accept a bit more braking force before lockup than the lighter diagonal. Use the brake force needed at each wheel to match rotor size, pad friction, and line pressure to that load split, especially after ballast or driver-position changes.