Truck Horsepower in South Africa: What 380, 420 and 550 Actually Buy You

In this market a truck is its horsepower. Nobody buys a “J5N” — they buy a 28.380, and the 380 is the power. It is the model name, the advert, the resale listing and the thing one operator tells another across a fuel forecourt.

This guide decodes those numbers using one manufacturer’s actual South African range, then does something most horsepower articles skip: it works out what the law actually requires. The answer is surprising, and it changes how you should think about the decision.

Reading the badge

Take FAW JH6 33.420 FT (6×4), a truck tractor sold in South Africa. Four parts:

• JH6 — the cab and platform range
• 33 — the mass class, in tonnes
• 420 — the horsepower
• FT — truck tractor. 6×4 is the axle configuration: three axles, two driven

How do we know the 420 is horsepower rather than something else? Because the manufacturer states the power separately, and it matches. FAW’s own description of the JH6 33.420FT says the engine produces “312 kW at 1 900 r/min and 1 900 Nm of torque from 1 200 r/min”. 312 kW is 418 hp. That is the 420 on the badge, rounded.

And where the manufacturer prints both units, they agree outright: the J7 28.550 is described as delivering “407 kW (546 hp)”. 546, badged 550.

One manufacturer’s truck-tractor range

FAW’s South African truck-tractor line-up, as listed by the manufacturer, reads as a horsepower ladder:

Model	Config	Badge hp	Manufacturer-stated power
15.180 FT	4×2	180	—
JK6 15.220 FD/FT	4×2	220	—
J5N 28.380 FT	6×4	380	— (Weichai WP10 six-cylinder)
J5N 33.420 FT	6×4	420	—
JH6 33.420 FT	6×4	420	312 kW · 1 900 Nm · 11 040 cc 6DM2
JH6 33.460 FT-AMT	6×4	460	—
JH6 28.500 FT	6×4	500	370 kW · 2 300 Nm · 13 ℓ 6DM3
JH6 28.550 FT	6×4	550	—
J7 28.550 FT/M · FT/P	6×4	550	407 kW (546 hp) · 2 600 Nm · 12,52 ℓ

180 to 550. That is the practical range on offer for tractor work, and the 6×4 line-haul models cluster from 380 upward.

Now the surprise: what the law requires

South African law does have an opinion about engine power, and it runs backwards from how buyers think. Regulation 239 does not set a minimum power for a truck. It sets a maximum mass for the power you already have:

permitted mass (kg) ≤ net engine power (kW) × 400

…where the drawing vehicle is a truck-tractor. For any other vehicle the multiplier is 240.

Run it on the three models where the manufacturer states a figure:

Model	Power	Mass Regulation 239 permits
JH6 33.420 FT	312 kW	124 800 kg
JH6 28.500 FT	370 kW	148 000 kg
J7 28.550	407 kW	162 800 kg

A fully loaded superlink runs around 56 tonnes. Turn the formula round and 56 000 ÷ 400 = 140 kW — about 188 hp.

So the smallest 6×4 tractor in that range is legally permitted to pull more than twice a standard superlink, and the biggest nearly three times it. The power-to-mass rule is not what limits you. Your axle mass limits and your combination mass limit bind long, long before Regulation 239 does.

Which means the honest answer to “how much horsepower does the law require?” is: far less than anything you would actually buy. The regulation exists to stop grossly underpowered vehicles crawling on public roads. It is a floor, and every modern tractor clears it easily.

So what actually decides?

If not the law, then four things — and they are all about your work, not the truck.

1. Gradient

A loaded combination on a long climb is where power stops being a specification and becomes a schedule. Two operators hauling identical mass, one on flat inland routes and one over an escarpment pass, sensibly buy different trucks. The escarpment operator is not buying speed; they are buying the ability to hold a gear.

2. Altitude

Much of South Africa’s freight moves across the highveld, well above sea level. Thinner air means a naturally aspirated engine makes less power — which is one reason essentially every heavy truck sold here is turbocharged and intercooled, including all the engines in the table above.

3. Mass — yours, not the maximum

Buying power for a 56-tonne combination when your work is a 28-tonne rigid load is money spent once and fuel spent every day. Match the power to what you will actually pull, most of the time.

4. Torque, and where it arrives

Peak horsepower is a headline; torque is what moves a loaded truck away from a stop and up a hill. The stated figures are worth reading closely — the JH6 33.420FT makes 1 900 Nm from 1 200 r/min, and the J7 makes 2 600 Nm.

The engine speed matters as much as the number. Torque available low down is torque you can use while pulling; torque that only arrives near the top of the rev range is torque you reach by changing down, repeatedly, on a climb.

A working approach

1. Start from your heaviest regular load, not the legal maximum.
2. Add your worst regular climb. The pass you cross every week sets the requirement; the flat leg does not.
3. Ask operators already running that lane what they use — and what they wish they had bought. This is the single most useful conversation available to you, and it is free.
4. Treat the legal minimum as irrelevant. It is, at these power levels.
5. Then check fuel. More power costs more to run when you are not using it. Power you never call on is the most expensive kind.

Questions people ask

What does 28.380 mean on a FAW truck?
28 is the mass class in tonnes and 380 is the horsepower. FT means truck tractor. So a 28.380FT is a roughly 28-tonne-class, 380 hp truck tractor.

How much horsepower do I need to pull a superlink?
Legally, about 188 hp — a fully loaded 56-tonne combination requires 140 kW under Regulation 239, and no modern tractor is anywhere near that low. Practically, the 6×4 tractors sold for this work start around 380 hp, and your route decides where in that range you should be.

Is more horsepower always better?
No. Power you do not use still costs you in purchase price and in fuel. Match it to your heaviest regular load and your worst regular climb, not to the biggest number available.

What is the difference between kW and horsepower?
Two units for the same thing. One kilowatt is about 1,34 horsepower, so 312 kW is about 418 hp. South African regulations are written in kilowatts; trucks are sold and talked about in horsepower.

Does torque matter more than horsepower?
For pulling a loaded combination away from a stop and up a gradient, torque — and particularly torque low in the rev range — is what you feel. Look at both figures and at the engine speed each is quoted at.

Where the numbers come from

• Model range and the three stated power figures — FAW Trucks Southern Africa, the manufacturer’s own South African website, read 16 August 2026. Power, torque and displacement quoted verbatim from their model descriptions.
• The power-to-mass rule — TRH 11, 8th Revision, Pretoria 2010, §3.6.1, reproducing Regulation 239 of the National Road Traffic Regulations.
• The permitted-mass column and the 140 kW figure — our own arithmetic from the regulation and the stated power. Shown so you can check it.
• The kW-to-hp conversion — 1 kW ≈ 1,341 hp. Verified against the manufacturer’s own dual-unit figure: they state 407 kW as 546 hp, and 407 × 1,341 = 546.

Why one manufacturer? Because we could verify their figures. Publishing a comparison table across every brand would have meant filling gaps with estimates, and an estimated horsepower figure is indistinguishable from a real one on the page. We would rather show one range properly than nine ranges approximately.

Check the current spec sheet before you buy. Model line-ups and engine ratings change, the figures above were read on one day, and the truck in front of you is the one that matters.

Next

• Trucks for road freight — the hub: body, rig and axles
• Axle mass limits — the rules that bind long before Regulation 239 does
• Truck makes and models — how to read the rest of the spec sheet
• Kweli Load Exchange — loads matched to your truck and corridor