The essentials first
The trailer and towing vehicle have separate HU deadlines.
Prepare lights, coupling, tyres, body and any brakes.
100 km/h use adds conditions for tyres and the vehicle combination.
The trailer has its own inspection deadline
The towing car’s HU does not cover the trailer. Use the trailer’s own sticker, registration certificate and vehicle category. Read the maximum authorised mass from its documents: the actual weight on a particular journey does not determine the inspection interval.
Heavier trailers generally have shorter intervals, and some heavy trailers require additional safety inspections. Annex VIII lists exceptions, including appropriately marked low-speed trailers. The usual car-trailer intervals therefore cannot be applied to every special-purpose trailer.
Test the lights with the towing vehicle connected
Connect the trailer and test indicators, brake lights, rear lights and number-plate lighting. Required rear fog lights and any other mandatory lamps must also work. A second person can watch the trailer while you operate the controls in the car.
Inspect the plug, adapter and cable. Loose contacts, damaged insulation or a cable dragging along the road may otherwise remain unnoticed. Clean dirty lamps and reflectors, and replace missing or damaged parts with suitable components.
A closer look
Up to 750 kilograms or without its own brakes
First HU after 36 months, then every 24 months.
Ordinary braked trailer above 750 kilograms up to 3.5 tonnes
HU generally every 24 months from first registration.
100 km/h use
Additional conditions, especially tyres less than six years old; no separate HU interval.
Inspect coupling, body and running gear
The coupling must close securely. Look for unusual play, damaged components and correct securing in accordance with the manufacturer’s instructions. On a braked trailer, include the breakaway cable and overrun mechanism in your preparation. Proper brake-performance testing requires suitable professional equipment and expertise.
The load floor, side panels and chassis should have no loose parts or dangerous damage. After a long period parked, pay particular attention to corrosion, wheel bearings and tyres. Even a low-mileage trailer may need repairs because of moisture or age.
Separate tread condition from the 100 km/h rules
Main tread must be at least 1.6 millimetres deep. Also check pressure, cracks, bulges and the appropriate load rating. A tyre with almost new-looking tread may still have been fitted a long time ago.
To use Germany’s 100 km/h trailer exemption, the trailer tyres must be less than six years old on each relevant journey and have a speed rating of at least L. Other conditions also apply to the combination. This age rule is not a universal HU age limit for all trailer tyres; damage can be a problem at any age.
Prepare the appointment practically
Bring registration certificate Part I and relevant documents for modifications or the 100 km/h approval. When booking, check that the chosen station can inspect your trailer’s size, weight and braking system.
An empty, clean and accessible trailer makes examination easier. Secure removable parts and clear objects covering components. The journey requires a suitable towing vehicle and a legal combination. An inspection booking does not override towing limits, driving-licence requirements or obvious safety defects.
- Check the trailer’s own sticker and maximum authorised mass.
- Test every light with the combination connected.
- Inspect coupling, securing equipment and cable for damage.
- Check tread, pressure and tyre age for 100 km/h use.
- Empty the load area and bring the vehicle documents.
Still have a question?
Does an unbraked 750-kilogram trailer need an HU?
Yes. For a newly registered trailer in this category, the first interval is generally 36 months, followed by 24-month intervals. Its own sticker shows the actual due date.
Are low-mileage tyres enough for 100 km/h use?
No. Among other conditions, the tyres must be less than six years old and have at least an L speed rating. Good tread alone is not enough.
Does a caravan have a different HU from a goods trailer?
Caravans are also trailers under Annex VIII. The HU interval depends particularly on maximum authorised mass and braking system. Any additional inspection obligations for fitted equipment must be considered separately.
Sources & further reading
- StVZO, Annex VIII – HU intervals and inspection findings (German)
- StVZO, Annex VIIIa – HU procedure and scope (German)
- StVZO, section 36 – tyres and tread (German)
- Ninth StVO Exemption Regulation, section 3 – tyres for 100 km/h use (German)