Answer grounded in published legislation
Your question
On a semi trailer, with double axles and gvm is less than 3499 kg, do both axles needs brakes?
For a semi-trailer with a GVM above 750 kg but not exceeding 3,500 kg, and not exceeding the drawing vehicle’s tare, the trailer must have a parking brake plus either an overrun brake or a service brake. Regulation 167 does not expressly require brakes on both axles. 1
However, if a service brake is fitted, the definition of “service brake” for a semi-trailer requires a braking system that brakes its wheels simultaneously. On the supplied wording, this indicates that both axles’ wheels must be braked simultaneously, rather than only one axle. 2
If the semi-trailer’s GVM is 750 kg or less, the requirements differ according to its mass relative to the drawing vehicle’s tare. 1
Verified sources
Where this answer comes from
Road Traffic and Transport Act 22 of 1999-Regulations 2001-053
(1) Subject to subregulation (4), a perso n may not operate a trailer on a public road if - (a) the mass of the trailer and any load thereon is 750 kilograms or less and - (i) does not exceed half of the tare of the drawing vehicle, unless that trailer is equipped with at least a parking brake or other device for keeping that trailer stationary; or (ii) exceeds half of the tare of the drawing vehicle but does not exceed such tare, unless that trailer is equi pped with a parking brake and either an overrun brake or a service brake; (b) the gross vehicle mass of the trailer exceeds 750 kilograms but does not exceed 3500 kilograms and does not exceed the tare of the drawing vehicle, unless that...
Road Traffic and Transport Act 22 of 1999-Regulations 2001-053
“service brake” means a brake, normally a footbrake, used in the ordinary course of events to reduce the speed of a vehicle or to stop the vehicle and which consists of - (a) a single braking system which brakes the front and rear wheels of the vehicle simultaneously or, in the case of - (i) a semi-trailer, brakes the wheels thereof simultaneously; (ii) a trailer, which according to the registration certificate thereof, was registered for the first time before 1 January 1983 and which is not a semi-trailer, brakes the front or rear wheels or all wheels thereof simultaneously; or (iii) a tractor, brakes the wheels of the rear axle or rear axle unit of the tractor simultaneously; or (b) two br...
Road Traffic and Transport Act 22 of 1999-Regulations 2001-053
Minimum equivalent braking force in N/kg 15 20 25 30 35 12 20 29 41 55 1,95 1,95 1,95 1,95 1,95 1,95 1,95 1,95 1,95 1,95 [Tables A-D amended by GN 98/2016 to correct a typographical error which actually appeared only in Tables A and C. ] (2) Compliance with the requirements contemplated in subregulation (1)(a) and (b) is determined by - (a) actual road tests conducted on a road with a reasonably level, dry, smooth and hard surface which is free from loose material and with the stopping distance measured from the moment the particular brake is applied with the engine disengaged until the vehicle comes to rest; (b) a suitable mechanical test; or (c) both tests contemplated in paragraphs (a) an...
Road Traffic and Transport Act 22 of 1999-Regulations 2001-053
(a) the wheel mass load of wheels - (i) which are fitted to a steering axle, exceeds 3 850 kilograms; or (ii) which are fitted to axles other than a steering axle, exceeds 4 000 kilograms; (b) the axle mass load of an axle fitted with two or three wheels and - (i) which is a steering axle, exceeds 7 700 kilograms; or (ii) which is an axle other than a steering axle, exceeds 8 000 kilograms; (c) the axle mass load of an axle fitted with four wheels and - (i) which is fitted to a vehicle designed to compact refuse and which is carrying such refuse, exceeds 10 200 kilograms; (ii) which is fitted to a breakdown vehicle, exceeds 10 200 kilograms; (iii) which is placed in the rear or middle of a b...
Road Traffic and Transport Act 22 of 1999-Regulations 2001-053
Minimum equivalent braking force in N/kg Light motor vehicle Heavy motor vehicle 35 35 14 16 4,4 4,4 4,4 4,4 TABLE B SERVICE BRAKE OF MOTOR VEHICLE OR COMBINATION OF MOTOR VEHICLES NOT CAPABLE OF EXCEEDING SPEED OF 35 km/ h Maximum initial speed in km/h Maximum stopping distance in metres Minimum declaration [deceleration] in m/s
Road Traffic and Transport Act 22 of 1999-Regulations 2001-053
(1) Subject to subregulation (2), a person may not, after 1 January 2002, operate on a public road a goods vehicle , with a gross vehicle mass which exceeds 3 500 kilograms, a minibus, bus or tractor which was registered for the first time on or af ter 1 January 1986, unless the brakes fitted thereto comply with the Standard Specification SABS 1207: 1985 “Motor vehicle safety standard specification for braking” published by the South African Government Notice No. 6 of 3 January 1986 or the Standard Specification SABS 1 051: 1980 “Motor vehicle safety specification for braking” published by the South African Government N otice No. 463 of