The Effect Of Increasing GCM On Fuel Economy

AWESYD2Onboard Weighing Brochure


Tests were run at the Goodyear San Angelo Proving Grounds to determine the effect of GCM (Gross Combination Mass) on vehicle fuel economy. As the truck’s gross weigh increases, fuel economy decreases.

The test data below confirms the fuel economy can be found by reducing the payload.

Goodyear San Angelo Proving Grounds

Overloaded Trucks, Will Empty Your Wallet, Because They Use More Fuel & Higher Maintenance Costs

Increasing the GCM (Gross Combination Mass) increases the engine demand horsepower and increases fuel consumption. Because gross combination mass is increased, Tyre rolling resistance increases, and vehicle kilometers per 100 liters decreases, assuming speed is maintained constant.

So by decreasing the GVM or GCM reduces fuel consumption and improves performance.

There’s a direct relationship between truck’s fuel consumption, power and engine load factors.

  • 25000 kg vs. 20500 kg @ 100 km/h – 427.67 L/100km penalty 8.5%
  • Increasing the GVM or the GCM / Towing increases the engine demand for power and increases fuel consumption. So by decreasing the GVW or GCW reduces fuel consumption and improves performance.
  • A 4500 kg increase in GVM or GCM will increase fuel consumption by about 8.5% (427.67 L/100km), which is the equivalent to a loss of 58.84 kilowatts at 70 km/h (or, if you’re old school that’s 80 engine horsepower at 43.5 MPH) on a 6% grade.
  • A 4500 kg reduction in payload will increase fuel savings by about 4.4%. A reduction in gross weight from 36000 kg to 27000 kg will generate an 8.8% improvement in fuel savings.
  • Pulling an empty trailer will increase fuel savings by 21%.

If Your Trucks Are Overloaded, Then You’re Wasting Money On Extra Fuel & Higher Maintenance Cost

So How Can Make Sure You Comply With The CoR Legislation And Save Money On Maintenance And Your Fuel Bill?