Comparison · 6×4 tractor unit · long haul at 19.3 t

Volvo FH, 345 kW, 6x4 tractor unit vs Volvo FM, 345 kW, 6x4 tractor unit, 12.8 L (2020–2023)

Volvo FH, 345 kW, 6x4 tractor unit

2013–2023 · 345 kW
36l/100 km
median; 32.7–40.6 across 5 declared configurations

Volvo FM, 345 kW, 6x4 tractor unit, 12.8 L (2020–2023)

2020–2023 · 345 kW
36.5l/100 km
median; 36.1–37.5 across 4 declared configurations
Volvo FH, 345 kW, 6x4 tractor unit and Volvo FM, 345 kW, 6x4 tractor unit, 12.8 L (2020–2023) side by side
SpecificationVolvo FH, 345 kW, 6x4 tractor unitVolvo FM, 345 kW, 6x4 tractor unit, 12.8 L (2020–2023)
Vehicle formTractor unit for semi-trailer (BC)RegisteredTractor unit for semi-trailer (BC)Registered
Axle configuration6×4Declared6×4Declared
Registered new2013–2023Registeredcentral 90% of records2020–2023Registeredcentral 90% of records
Engine power345 kWDeclared345 kWDeclared
Engine displacement12.8 litresDeclared12.8 litresDeclared
GearboxautomatedDeclaredautomatedDeclared
Emission classEURO 6, EURO VI B, EURO VI CRegisteredEURO VI B, EURO VI DRegistered
Gross vehicle weight29,000–35,000 kgRegisteredmedian 31,000 kg, across 3 type-approval versions and 1 record without one29,000–32,000 kgRegisteredmedian 29,000 kg, across 1 type-approval version and 1 record without one
Kerb weight9,366–14,435 kgRegisteredmedian 9,366 kg, over 6 registrations9,361–20,130 kgRegisteredmedian 9,361 kg, over 2 registrations
Wheelbase4,370–4,770 mmRegisteredmedian 4,570 mm, over 6 registrations4,770 mmRegistered
Overall length6,740–7,160 mmRegisteredmedian 6,740 mm, over 6 registrations6,940–7,400 mmRegisteredmedian 6,940 mm, over 2 registrations
Declared fuel, long haul36 l/100 km Declaredmedian; 32.7–40.6 l/100 km across 5 declared configurations36.5 l/100 km Declaredmedian; 36.1–37.5 l/100 km across 4 declared configurations
CO₂ per tonne-km48.9 g Declaredmedian; 44.31–55.08 g49.4 g Declaredmedian; 48.97–50.81 g

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

What the numbers actually say

There is 0.5 l/100 km between these two (1.3%). 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 600 litres a year (£840). The declared figures for one of them alone span 7.9 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
Volvo FH, 345 kW, 6x4 tractor unit43,200 litres
£60,480 at the assumed price
Volvo FM, 345 kW, 6x4 tractor unit, 12.8 L (2020–2023)43,800 litres
£61,320 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.