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How the machine is put together

Axles, gearbox, engine, cab. What the specification sheet is actually describing, and which choices you live with for the vehicle’s whole life.

8 articles

Axle configurations explained: 4x2, 6x2, 6x4 and 8x4What 4x2, 6x2/4 and 8x4/4 actually mean, the EU axle and weight limits sitting behind them, and which configuration belongs on which job.6 October 2026 · 4 sources
Truck cabs: classes, heights and sleeper typesWhat GigaSpace, Globetrotter XL and XG+ actually describe: day cab versus sleeper, interior standing height, flat floors, low-entry cabs, and the EU rules behind all of them.8 October 2026 · 9 sources
Aerodynamic cabs and the EU length rulesDirective 96/53/EC caps an articulated vehicle at 16.50 m. Articles 8b and 9a let an aerodynamic cab or a rear device exceed it, on the condition that the extra length buys no load.25 September 2026 · 12 sources
kW, hp and Nm: how to read a truck's power figuresWhy a truck's horsepower sits beside the kilowatts it is approved in, what a torque figure at 900 rpm is telling you, and the 5 kW per tonne that EU type-approval law requires.24 September 2026 · 23 sources
Automated manual transmissions in heavy trucksWhy almost every European heavy tractor now shifts itself, how an automated manual differs from a torque-converter automatic, and why the gearbox is now a CO2-certification component under EU law.8 October 2026 · 9 sources
Axle ratios and final drive: single reduction, hub reduction and portalWhat the 2.31 or 5.41 on a rear axle line counts, the five axle types Regulation (EU) 2017/2400 defines, and why the portal axle exists — for ground clearance or a low city bus floor.23 September 2026 · 10 sources
Turbocompound engines: what they are and the work they are built forWhat a second exhaust turbine does, the fuel figures manufacturers publish and what they are measured against, and the work the makers say it is built for.24 September 2026 · 10 sources
What is a retarder? Retarders, engine brakes and what UN R13 requiresA retarder slows a heavy vehicle on long descents without the service brakes. Hydrodynamic retarder, exhaust brake and compression brake, and what UN R13 asks of which vehicles.1 October 2026 · 10 sources