Legal Truck Dimensions and Mass in South Africa

A truck on a South African public road may not exceed 2.6 m wide or 4.3 m high, and its length limit depends on what it is: 12.5 m for a rigid vehicle, 18.5 m for a truck-tractor and semi-trailer, and 22 m for any other combination such as an interlink. Exceed any of those and the load is abnormal, and needs a permit.

These are the numbers that decide what fits on a trailer, what needs a permit, and what a traffic officer measures at the roadside. They come from the National Road Traffic Regulations and are reproduced in TRH 11, the Department of Transport’s standard.

The legal dimensional limits

Vehicle type	Overall length	Overall width	Overall height
Single (rigid) vehicle excluding a semi-trailer	12.5 m	2.6 m	4.3 m
Articulated vehicle truck-tractor and semi-trailer	18.5 m	2.6 m	4.3 m
Other combinations interlinks, multiple trailers	22.0 m	2.6 m	4.3 m

Two points that catch operators out. Length includes load projections — a pipe hanging over the back counts. And the width limit is 2.6 m on the widest point, which includes mirrors on some measurements and load overhang on all of them.

What these limits look like

An articulated combination — a truck-tractor and one semi-trailer — has 18.5 m to work with. The trailer itself is typically 13.6 m, and the tractor and coupling take up the rest.

A superlink or interlink is two linked trailers behind one tractor, and falls under “other combinations” at 22 m. The extra 3.5 m over an articulated vehicle is what buys the second trailer — which is why the lead trailer is short, commonly 6.1 m against 12.2 m on the rear.

Mass: the two ways to be overloaded

Mass abnormality works differently from dimension. TRH 11 puts it plainly: a mass abnormality exists when “the allowable mass of the vehicle/combination or one or more axle groups exceeds the legal limitations.”

That “or” matters more than most operators realise. A combination can be within its total permitted mass and still be illegal because one axle group is over. Loading a trailer nose-heavy puts mass onto the tractor’s drive axles; loading it tail-heavy puts it on the trailer bogie. The total on the weighbridge is unchanged. The distribution is what fails you.

Three ratios in TRH 11 govern how mass may be distributed, and all three are checkable at the roadside:

• Power-to-mass ratio — the drawing vehicle must have enough engine for what it is pulling.
• Traction ratio — enough of the mass must sit on the drive axles for the combination to pull and, more importantly, to stop.
• Steering ratio — enough mass must remain on the steering axle to steer. Load a trailer too far back and you lift the front of the tractor; the vehicle is legal on total mass and unsafe to drive.

The axle massload table (regulation 240)

Total mass is only half the test. Regulation 240 sets a limit for each axle and axle group, and a combination can sit inside its permitted total and still be illegal because one group is over. These are the numbers a weighbridge checks.

Axle type	Single axle	Tandem axle unit	Tridem axle unit
Steering axles	7 700 kg	15 400 kg	23 100 kg
Non-steering axles single tyres	8 000 kg	16 000 kg	24 000 kg
Axles with dual wheels 4 tyres per axle	9 000 kg	18 000 kg	24 000 kg

Three things in that table are worth reading twice:

• The tridem dual-wheel figure is a cap, not a multiple. Steering and non-steering scale cleanly (7 700 → 15 400 → 23 100; 8 000 → 16 000 → 24 000), but dual wheels go 9 000 → 18 000 → 24 000, not 27 000. A third dual-wheel axle buys you 6 000 kg, not 9 000. Operators who assume the pattern holds will load a tridem 3 000 kg over.
• A steering axle carries less than a non-steering one — 7 700 against 8 000. The 7 700 figure derives from a standard for 2 × 11.00:20 cross-ply tyres at 480 kPa, a tyre that left the road decades ago, and industry has argued for harmonising it to 8 000 kg. It has not been changed, so 7 700 is the number you are measured against.
• Dual wheels buy 1 000 kg per axle over single tyres — 9 000 vs 8 000 — because the load is spread across four contact patches instead of two.

The other mass limits that travel with it

Limit	Value
Bridge formula — mass permitted across a group of axles	P = 18 000 + (2 100 × L) kg, where L is the distance in metres from the centre of the first axle of the group to the centre of the last
Power-to-mass	Combination mass in kg may not exceed net engine power in kW × 240
Traction — minimum on the driving axles	20% of GCM, laden or unladen
Steering — minimum on the steering axles	11% of gross mass (articulated vehicle) · 20% (non-articulated) · 30% (fitted with a steering axle unit)
Combination make-up	A drawing vehicle plus one or two trailers. A converter dolly used with a semi-trailer is deemed not to be a trailer
Maximum permissible combination mass	56 000 kg — see the sourcing note below

The steering minimums are the ones that surprise people, because they are a floor, not a ceiling. Load a trailer too far back and you lift mass off the front of the tractor: the combination can be under every maximum in the table above and still illegal — and, more to the point, hard to steer and slow to stop.

Correction: this page previously declined to publish this table

An earlier version of this page carried a section headed “What this page does not tell you: the axle massload table”, which said we had deliberately not published axle massloads because we could not verify them to the standard the rest of the page is held to. That was accurate when written, and the reasons were specific: TRH 11 reproduces the limits as a diagram (Figure 3.1) that did not survive text extraction with its labels attached to the right configurations; two secondary sources disagreed, one giving 8 000 kg for a steering axle and another 3 850 kg; and the government copy of the regulation would not open.

All three have now been resolved, so the table is published:

• The diagram does extract — from Revision 2 (September 2017) of TRH 11, which we had not read. The earlier attempt used the 2010 original.
• The two “contradictory” sources were never in conflict. 7 700 kg is the steering-axle limit; 3 850 kg is the per-wheel half of it; and 8 000 kg is a proposed harmonisation with the Tripartite region — not current South African law. A number without its unit is not a fact, and that is what made them look contradictory.
• Every figure is corroborated by two independent sources — TRH 11 (Department of Transport) and a manufacturer’s summary of the Act — which agree on all six shared values. TRH 11 additionally supplies the steering tandem and tridem figures the manufacturer summary omits.

One figure above is single-sourced and flagged as such: the 56 000 kg maximum permissible combination mass. It comes from the manufacturer summary; TRH 11 does not reproduce it, and we have not read regulation 239 directly. Treat it as indicative and confirm it before relying on it — unlike every other number on this page, it does not yet meet the two-source standard.

Overloading: what it actually costs

Overload control in South Africa is enforced at weighbridges on the major corridors, and the consequences are not only the fine:

• The vehicle is stopped until the overload is corrected, which usually means a second truck to the weighbridge and a transfer at the roadside.
• The delay lands on a load with a delivery commitment, so the cost of an overload is the fine plus the standover, plus whatever the missed slot costs at the other end.
• Pavement damage rises sharply with axle load, not linearly — which is why enforcement targets axle groups rather than gross mass.

The practical defence is loading discipline: know your tare, know your axle distribution, and weigh before you leave rather than after you are stopped.

On a dangerous goods vehicle the calculus changes: SANS 10231 treats a cargo transfer following an overload as an incident, which means the emergency services must be notified and a qualified person must supervise the transfer. An overload on a tanker is not the same problem as an overload on a tautliner.

When you exceed these limits

Exceeding any dimensional or mass limit makes the load abnormal, and it may then travel only under an exemption permit issued in terms of Section 81 of the National Road Traffic Act — provided the load is indivisible. See our guide to abnormal load permits in South Africa for the dimension and mass classes, the route categories, and how many escort vehicles each combination requires.

Source and currency

Source: TRH 11, Dimensional and Mass Limitations and Other Requirements for Abnormal Load Vehicles, 8th revision, Pretoria 2010 — Tables 2.1 and 2.2, and sections 1.2.2, 3.6, 3.7 and 3.8. Dimensional limits are set by regulations 221 and 224(b), and axle massloads by regulation 240, of the National Road Traffic Regulations 2000 under the National Road Traffic Act 93 of 1996. TRH 11 is published by the Department of Transport.

Current as at 14 August 2026. Dimensional limits are stable and change rarely. Confirm anything you are loading against with your provincial overload control unit before you rely on it.

Loading against these limits

If you are working out what will fit and what it will cost to move, our freight rate calculators price a load by route and vehicle. To find freight that suits the truck you actually run, list it free on the Kweli Load Exchange — shippers search by vehicle type and corridor, so a correctly specified truck gets matched to loads it can legally carry.

The 3,500 kg GVM line also decides operator registration. See what a goods operator must actually register for.

Dimensions are checked at the roadside; fitness is checked annually. See roadworthy certificates for trucks in South Africa.