Axle load is the share of a vehicle’s weight carried by one axle or axle group. The front and rear loads depend on where the cab, body, equipment, passengers and payload sit relative to the axles. A vehicle can be below its overall GVM and still overload an axle, tyre or suspension component.

Why it matters for a truck build

A crane, tank, tipper body, hooklift, tailgate or tow coupling changes where weight acts on the chassis. Moving equipment rearward can take load off one axle and add it to another. The same truck can have very different axle loads when empty, carrying payload or towing.

Which limits apply?

An engineering check considers the manufacturer’s vehicle and component ratings as well as applicable operating mass limits. The NHVR explains that heavy vehicles must not exceed the manufacturer’s ratings even when a legal mass limit would otherwise allow more. Axle spacing, tyre capacity and intended operating conditions also matter. A calculation is only as reliable as the dimensions, masses and configuration supplied.

What CVC needs for a calculation

• Vehicle make, model, VIN, wheelbase and axle layout.
• GVM, GCM and axle or axle-group ratings.
• Body and equipment drawings, masses and positions.
• Expected payload and where it sits, including any towing load.
• Measured after-modification weight and axle weights when available.

CVC can model proposed load cases, identify the limiting axle or component and provide a calculation report for a suitable configuration. If the results show an overload, the assessment can guide a change to equipment position, load distribution or scope before the build is finalised. See our axle-load calculation service or worked example. Submit the available configuration details for a scoped quote.

Official references: NHVR General Mass Limits and manufacturer’s mass limits.