Comparison · 4×2 tractor unit · long haul at 19.3 t

Mercedes-Benz Arocs, 350 kW, 4x2 tractor unit vs Volvo FMX, 345 kW, 4x2 tractor unit, 10.8 L (2021–2023)

Mercedes-Benz Arocs, 350 kW, 4x2 tractor unit

2020–2023 · 350 kW
35.6l/100 km
median; 32.1–39.5 across 31 declared configurations

Volvo FMX, 345 kW, 4x2 tractor unit, 10.8 L (2021–2023)

2021–2023 · 345 kW
36l/100 km
median; 34.7–37.8 across 5 declared configurations
Mercedes-Benz Arocs, 350 kW, 4x2 tractor unit and Volvo FMX, 345 kW, 4x2 tractor unit, 10.8 L (2021–2023) side by side
SpecificationMercedes-Benz Arocs, 350 kW, 4x2 tractor unitVolvo FMX, 345 kW, 4x2 tractor unit, 10.8 L (2021–2023)
Vehicle formTractor unit for semi-trailer (BC)RegisteredTractor unit for semi-trailer (BC)Registered
Axle configuration4×2Declared4×2Declared
Registered new2020–2023Registeredcentral 90% of records2021–2023Registeredcentral 90% of records
Engine power350 kWDeclared345 kWDeclared
Engine displacement12.8 litresDeclared10.8 litresDeclared
Gearboxautomated, manualDeclaredautomatedDeclared
Gross vehicle weight18,000–20,500 kgDeclaredmedian 18,000 kg, across 114 declared configurations21,000–22,000 kgDeclaredmedian 21,000 kg, across 7 declared configurations
Declared fuel, long haul35.6 l/100 km Declaredmedian; 32.1–39.5 l/100 km across 31 declared configurations36 l/100 km Declaredmedian; 34.7–37.8 l/100 km across 5 declared configurations
CO₂ per tonne-km48.2 g Declaredmedian; 43.55–53.6 g48.75 g Declaredmedian; 47.08–51.2 g

Fuel and CO₂: long haul at 19.3 t, 2022 declarations.

What the numbers actually say

There is 0.4 l/100 km between these two (1.1%). That is inside the 10% tolerance of declared figures, so on fuel alone neither is the better choice: at 120,000 km a year and an assumed £1.40 a litre the gap would be about 480 litres a year (£672). The declared figures for one of them alone span 7.4 l/100 km across its configurations, so the specification ordered matters more than the choice between these two.

Fuel over a year

120,000 km · assumed price
Mercedes-Benz Arocs, 350 kW, 4x2 tractor unit42,720 litres
£59,808 at the assumed price
Volvo FMX, 345 kW, 4x2 tractor unit, 10.8 L (2021–2023)43,200 litres
£60,480 at the assumed price
At 120,000 km a year and an assumed £1.40 a litre; the price is an assumption, not one we track.