An unbraked trailer may be at most 750 kg, and in practice often less. In GB and NI the car’s kerb weight must be at least twice the laden trailer. In Ireland a trailer heavier than half the loaded towing vehicle must have brakes. The car’s own unbraked limit may be lower still.
Great Britain and Northern Ireland
A trailer that weighs over 750 kg loaded must have a working brake system (GOV.UK, nidirect). The construction and use regulations add a second test: an unbraked trailer must not be drawn by a vehicle "of which the kerbside weight is less than twice" the laden trailer (GB reg 87, NI reg 101). GOV.UK words this as "should", but it is in the regulations.
So a 1,100 kg hatchback can pull an unbraked trailer of at most 550 kg laden, however the trailer is plated.
Ireland
Every trailer "exceeding in weight laden 15 cwt. or half the weight laden of any drawing vehicle" needs brakes and an automatic stop device (S.I. 190/1963). The RSA says all trailers over 750 kg DGVW need a service brake, handbrake and breakaway brake (RSA). Here it is the loaded car that counts, so Towsheet uses your loaded weight, or the kerb weight if you don't give one.
Secondary couplings
Unbraked trailers need a secondary coupling, such as a chain or cable, so the drawbar can't hit the road if the hitch fails (GOV.UK).
Questions
- Can a car tow a 750 kg unbraked trailer?
- Only if the car’s unbraked towing limit allows it and, in GB and NI, the car’s kerb weight is at least 1,500 kg (twice 750 kg).
- Does the half-weight rule use the laden trailer?
- Yes: the trailer’s unladen weight plus its load. In Ireland it is compared with the loaded weight of the towing vehicle.
Sources
- Trailers over 750 kg need brakes: GOV.UK, Towing with a car, checked 3 November 2026.
- NI: trailers over 750 kg need brakes: nidirect, Towing safety information, checked 3 November 2026.
- Unbraked trailers: no more than half the car’s kerb weight: Road Vehicles (Construction and Use) Regulations 1986, regulation 87, checked 3 November 2026.
- NI unbraked trailers: no more than half the car’s kerb weight: Motor Vehicles (Construction and Use) Regulations (Northern Ireland) 1999, regulation 101, checked 3 November 2026.
- Ireland: half the laden weight of the towing vehicle: Road Traffic (Construction, Equipment and Use of Vehicles) Regulations 1963, S.I. No. 190 of 1963, checked 3 November 2026.
- Ireland: trailers over 750 kg need full brakes: RSA, Braking requirements for light trailers, checked 3 November 2026.
- Breakaway cable or secondary coupling: GOV.UK, Towing with a car, checked 3 November 2026.
Guidance, not legal advice. Towsheet is independent and not connected with the DVLA, DVA, RSA or NDLS.