Calculate vehicle unsprung weight from wheel, tire, brake, and suspension weights, or estimate total unsprung weight and curb weight percentage.

Use one corner throughout. Count only the effective unsprung portion of shared suspension parts, including hubs/axles in an appropriate category without double counting. Preset suggestions are illustrative numbers, not vehicle specifications.

Related Calculators

Unsprung Weight Formula

The following formula adds the unsprung component weights for one corner of a vehicle. For a vehicle total, sum all corners or multiply a representative average corner by the number of wheels:

UW = WW + TW + BW + SW

Variables:

  • UW is the unsprung weight (lbs)
  • WW is the weight of the wheels (lbs)
  • TW is the weight of the tires (lbs)
  • BW is the weight of the brakes (lbs)
  • SW is the weight of the suspension components (lbs)

For one corner, add the wheel, tire, brake, and effective unsprung portion of the suspension components. Allocate shared parts appropriately and include hubs or axles without double counting; not every suspension part is entirely unsprung.

What is Unsprung Weight?

Unsprung weight refers to the mass of the vehicle that is not supported by the suspension system. This includes components such as the wheels, tires, brakes, and parts of the suspension itself. Unsprung weight affects the vehicle’s handling and ride quality, as it can influence the suspension’s ability to isolate the vehicle’s body from road irregularities. Reducing unsprung weight can lead to improved handling and faster suspension response.

How to Calculate Unsprung Weight?

The following steps outline how to calculate the Unsprung Weight.

  1. First, determine the weight of the wheels (WW) in pounds.
  2. Next, determine the weight of the tires (TW) in pounds.
  3. Next, determine the weight of the brakes (BW) in pounds.
  4. Next, determine the weight of the suspension components (SW) in pounds.
  5. Next, gather the formula from above = UW = WW + TW + BW + SW.
  6. Finally, calculate the Unsprung Weight (UW) in pounds.
  7. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Wheel Weight (WW) = 20 lbs

Tire Weight (TW) = 25 lbs

Brake Weight (BW) = 15 lbs

Suspension Weight (SW) = 10 lbs