The amount of weight you can carry as payload on a trailer in the UK depends on a number of factors which can get confusing.
As a simple process, you should be thinking about the following in order:
- Establish the maximum gross vehicle weight
- Work out the payload potential
- Is the trailer suitable for carrying the payload potential?
- Are the axles being overloaded?
1: GVW or GCW (Gross Vehicle Weight or Gross Combination Weight)
GCW refers to the maximum plated total weight of the tractor, trailer and payload.
The following refers to GCW/GVWs described by the DfT in the UK:
| Axles | Max Combination Weight | Notes |
|---|---|---|
| 6 (3-axle tractor unit with 3-axle trailer) | 44,000 kgs* | See notes (b) and (d) |
| 5 (3-axle tractor unit with 2-axle trailer or 2-axle tractor unit with 3-axle trailer) | 40,000 kgs | See note (a) |
| 4 (2-axle tractor unit with 2-axle trailer) | 36,000 kgs / 38,000 kgs* | |
| 3 (2-axle tractor unit with 1-axle trailer) | 26,000 kgs |
* If the driving axle, if it is not a steering axle, has twin tyres and road-friendly suspension, or each driving axle is fitted with twin tyres and the maximum weight for each axle does not exceed 8.55 tonnes.
** Distance between the rear axle of the motor vehicle and the front axle of the trailer is not less than 3 metres.
(a) Five-axle artic or drawbar may alternatively comprise a 3-axle motor vehicle and a 2-axle trailer.
(b) Conditions: each vehicle must have at least three axles; the drive axle must have twin tyres and road-friendly suspension with a maximum of 10.5 tonnes, or each driving axle must have twin tyres and a maximum of 8.5 tonnes; and the trailer must have road-friendly suspension.
(c) Conditions for operation on five axles: must have three axles on the tractor unit, carry a single 40-ft ISO container only, and be used for international journeys.
(d) Powered by a low-pollution engine (at least Euro 2).
EU
The weight limits in the EU are very similar, with the exception that there is a 40,000 kg capped GVW limit.
ZEVs
It is possible to have a battery electric truck (ZEV) plated or re-plated by the DVSA so that the GCW is increased by 2,000 kgs, provided that the GCW does not exceed 44,000 kgs.
As an example, a diesel-powered 40-tonne combination could be re-plated to 42 tonnes if the truck is a ZEV. Equally, a 38-tonne combination could be re-plated to 40 tonnes if the truck was a ZEV.
The weight of a ZEV compared to a diesel equivalent is irrelevant. If a ZEV weighs more than its diesel equivalent plus 2,000 kgs, then your payload potential will be reduced accordingly.
GVW and "O" Licence Registration
As operators are required to register what GVW they want an artic combination to run at (and pay the relevant licence fee), it is possible to downrate this limit, so it’s important to understand what is covered on your "O" licence. For instance, a 3-axle tractor unit with 3-axle trailer could be rated at 44 tonnes max, but it could be registered on the "O" licence at just 38 tonnes to reduce the licence fee.
2: Working Out Your Payload Potential
Once you understand your maximum GVW, the next thing to consider is the unladen weight of both your tractor and trailer (TARE weight).
Examples:
44-tonne GVW: A 3-axle diesel tractor unit may weigh circa 8,500 kgs coupled with a tri-axle trailer weighing 7,500 kgs. This totals 16,000 kgs. Your maximum potential payload can then be calculated as the maximum GVW less 16,000 kgs. The payload potential would therefore be 28,000 kgs.
40-tonne GVW: A 2-axle diesel tractor unit may weigh circa 7,500 kgs coupled with a tri-axle trailer weighing 7,500 kgs. This totals 15,000 kgs. Your maximum potential payload can then be calculated as the maximum GVW less 15,000 kgs. The payload potential would therefore be 25,000 kgs.
26-tonne GVW: An urban 2-axle diesel tractor unit may weigh circa 5,500 kgs coupled with a single-axle trailer weighing 5,000 kgs. This totals 10,500 kgs. Your maximum potential payload can then be calculated as the maximum GVW less 10,500 kgs. The payload potential would therefore be 15,000 kgs.
3: Gross Trailer Weight
All this assumes that the trailer itself is designed to carry your payload potential. Not all trailers are designed the same, and each manufacturer will state a Gross Trailer Weight. This is the maximum weight the trailer is designed to operate at (including payload). For instance, if the Gross Trailer Weight is 30,000 kgs and the trailer TARE weight is 10,000 kgs, then you have an additional payload restriction of 20,000 kgs max.
4: Axle Overloading
Finally, once you understand your maximum payload potential, the last thing to consider is whether that payload might overload the trailer axle set (or bogie). Although each axle may have its own manufacturer’s weight rating, the legal maximums for axle groups (bogies) are capped irrespective of higher component ratings.
| Axle Configuration | Maximum Legal Bogie Load | Notes |
|---|---|---|
| Single axle | Up to 10,000 kgs | Requires 10-tonne rated axle and tyres. Most standard 385/65 R22.5 setups are rated at 9,000 kgs. |
| Tandem (2-axle) bogie | 18,000–20,000 kgs | 18,000 kgs standard with 1.3–1.8 m spacing and 9-tonne axles. 20,000 kgs possible if spacing exceeds 1.8 m and both axles/tyres are rated at 10 tonnes each. |
| Tri-axle bogie | 24,000 kgs (capped) | Legal maximum regardless of axle, tyre or spacing configuration. |
Legal bogie limits also depend on the spacing between the axles. For tandem sets, the standard legal maximum of 18,000 kgs applies where the axle centres are spaced between approximately 1.3 m and 1.8 m. If the spacing exceeds 1.8 m and both axles and tyres are rated for 10 tonnes each, the bogie limit may increase to 20,000 kgs. Spacings below 1.3 m reduce the permitted load accordingly.
Tri-axle bogies are capped at 24,000 kgs regardless of spacing, and single-axle bogies remain limited to 9,000–10,000 kgs depending on component ratings. These spacing provisions are set out in Schedule 11 of the Road Vehicles (Construction & Use) Regulations 1986 (as amended).
In practice, most tri-axle trailers operate with 9-tonne rated axles and tyres, giving a theoretical 27,000 kg bogie capacity, but the legal cap remains 24,000 kgs. The same capped principle applies for two-axle and single-axle configurations, even where the sum of component ratings suggests otherwise.
It’s also important to consider load distribution. A poorly balanced or front-heavy load can easily exceed the rated load on the trailer’s bogie even if the total combination weight remains within limits. Always confirm axle weights on a calibrated weighbridge, or estimate them using a payload distribution calculator.
