Vehicle documents
Trailer: how can you tell whether an axle is overloaded?
A combination can be below its total mass limit while an axle is overloaded; check the distribution, plate and individual axle weights.
A trailer can remain under its total authorised mass and still overload one axle. Compare the actual load on each axle with the limits in the vehicle documents and manufacturer plate. Load distribution and vertical coupling load must be checked separately.
Total mass and axle load are separate limits
Article 62 sets limits on total mass and on the loads carried by individual axles. The applicable maxima vary by trailer type, axle count and configuration; the vehicle’s own approved limits also apply. A total weight below the maximum authorised mass does not prove that every axle is within its limit.
For example, cargo concentrated toward the front can put too much weight on the front axle while keeping the overall mass below the maximum. Uneven distribution can overload tyres, suspension, hubs and brakes and reduce stability. Check the vertical load at the coupling too: it transfers weight to both trailer and towing vehicle.
How to make a useful check
Read the trailer document and manufacturer plate for maximum mass, axle loads and approved tyres. After loading the trailer as it will travel, use suitable scales that measure each axle separately; a single total weigh-in is not enough. The measurement should reflect the real setup, including cargo, accessories and its distribution.
Move or spread the cargo while respecting the coupling load and securing it against movement. Do not raise a limit by changing tyres or moving the load; technical changes may require approval. If a value is near its maximum or the trailer has closely spaced axles, use a properly equipped weighing centre.
Example
A trailer with an authorised mass of 2,000 kg might weigh 1,850 kg in total and still be outside its limit if one axle carries more than the approved amount. Repositioning cargo toward the centre may fix distribution only if axle limits, coupling load, total mass and the car’s capacity all remain within their limits.
Quiz Patente Ufficiale offers theory quizzes and mistake review; measuring axle loads requires separate weighing in the configuration used for travel.
Quiz Patente Ufficiale helps review theory quizzes and mistakes; axle loading needs a separate measurement and the trailer’s approved limits.
Frequently asked questions
If the trailer is below its authorised total mass, are the axles necessarily within limits?
No. One axle can be overloaded even when the trailer’s total mass is below its maximum.
Does a total weigh-in reveal an overloaded axle?
No. You need a scale that measures each axle separately.