What the exam asks here: Everyone in the queue at the Praxis shouts the same answer: '75 kilos, right?' The CBR exam designer knows you have picked up that number somewhere — and counts on exactly that.
Many learners think: The nose weight of a trailer may never be more than 75 kg.
The rule is: There is no '75 kg' in the book. Up to 750 kg TMM a maximum of 50 kg applies; above 750 kg TMM a minimum of 1% of the permitted maximum mass applies. '75 kg' is a quick-prep rule of thumb, not a book limit
Everyone in the queue at the Praxis shouts the same answer: '75 kilos, right?' The CBR exam designer knows you have picked up that number somewhere — and counts on exactly that. The book has no 75 kg. It gives a rule with TWO branches: a ceiling under 750 kg, a floor above it. Once you know which branch applies when, you see through every '75 kg' trap.
Centre-axle trailer up to 750 kg: at most 50 kg nose weight (Book p.230) — that is a hard ceiling. Heavier than 750 kg? Then the rule flips: the nose weight may not be less than 1% of the permitted maximum mass. No more ceiling — a floor.
The rule applies specifically to the centre-axle trailer (Book p.230): wheels roughly in the middle, drawbar resting on the tow ball — most caravans and boat trailers. Under 750 kg permitted maximum mass, 50 kg is a hard ceiling: too much downward load overloads the tow ball and pushes the car's rear down. Above 750 kg it flips: too little nose weight makes the trailer unstable instead. That minimum is 1% of the permitted maximum mass — at 1,200 kg that is at least 12 kg. The well-known '75 kg' comes from quick-prep rules of thumb for unknown manufacturer specs, not from this book — don't confuse it with the max. 50 kg or the min. 1% rule. A nuance the book itself does not state: that 1% minimum does not keep rising without limit. Per the vehicle regulations the nose weight never needs to exceed 50 kg, even though 1% of a still heavier TMM would arithmetically be higher — at 5,000 kg TMM the minimum already plateaus at 50 kg.
Wrong nose weight is dangerous in two opposite directions. Too much pushes the car's nose up and the rear down — worse steering, less front grip. Too little makes the trailer unstable: on the bridge at Moerdijk, where the westerly wind pushes trucks and caravans sideways, an under-loaded centre-axle trailer becomes an unstable snaking machine at high speed. Two different kinds of limits, not one simple number that applies everywhere.
It is half past six in the evening, dusk, and the digital speed signs show 100. You are driving with a centre-axle trailer (caravan) of 1,200 kg permitted maximum mass. What applies to the nose weight?
Explain: which nose-weight rule applies under 750 kg, which above it, and why is '75 kg' not a book rule for these two cases?
≤750: 50 max. >750: min. 1% of the TMM. 75 kg is not a book figure, only a fallback.
Saturday morning at the Praxis in Utrecht, you and your brother-in-law lift a cement mixer onto his caravan-style trailer (permitted maximum mass 500 kg). The drawbar pushes heavily on the tow ball. How much nose weight may that trailer have at most?
Centre-axle trailer up to 750 kg: at most 50 kg nose weight (Book p.230) — that is a hard ceiling. Heavier than 750 kg? Then the rule flips: the nose weight may not be less than 1% of the permitted maximum mass. No more ceiling — a floor.
Correct answer: 50 kg
Correct: 50.0 kg (±5.0).
Correct answer: At least 12 kg
False — you turn the lower limit into an upper limit. Above 750 kg the nose weight may not be less than 1% of the permitted maximum mass: 12 kg is the minimum here, more is allowed
Why learners get this wrong: The maximum nose weight of 50 kg applies to centre-axle trailers above 750 kg permitted maximum mass.
Correct answer: Neither complies: no. 1 is above the 50 kg max, no. 2 is below the 1% of 900 kg min (9 kg)
Why learners get this wrong: The maximum nose weight of 50 kg applies to centre-axle trailers above 750 kg permitted maximum mass.
Correct answer: The centre-axle trailer
Why learners get this wrong: The nose-weight requirements (max. 50 kg / min. 1% TMM) apply to every trailer, regardless of type.
Correct answer: False
Why learners get this wrong: For a centre-axle trailer above 750 kg, the nose weight may be at most 1% of the permitted maximum mass.
Correct answer: For a centre-axle trailer above 750 kg, the nose weight may be at most 1% of the permitted maximum mass.
'may not be less than 1%' is a minimum, not a maximum. At 1,200 kg TMM the nose weight must therefore be at least 12 kg; more is always allowed
Why learners get this wrong: The nose-weight requirements (max. 50 kg / min. 1% TMM) apply to every trailer, regardless of type.
Correct answer: At least 12 kg (1% of 1,200 kg) — less is not allowed
≤750: 50 max · >750: 1% TMM min
Why learners get this wrong: The nose weight of a trailer may never be more than 75 kg.
Correct answer: The nose-weight requirements (max. 50 kg / min. 1% TMM) apply to every trailer, regardless of type.
The text literally refers to 'the load under the coupling of a centre-axle trailer'. This atom is limited to that type
Why learners get this wrong: The maximum nose weight of 50 kg applies to centre-axle trailers above 750 kg permitted maximum mass.
Correct answer: True
The text literally refers to 'the load under the coupling of a centre-axle trailer'. This atom is limited to that type
Why learners get this wrong: The nose-weight requirements (max. 50 kg / min. 1% TMM) apply to every trailer, regardless of type.
No. There is no '75 kg' in the book. Up to 750 kg TMM a maximum of 50 kg applies; above 750 kg TMM a minimum of 1% of the permitted maximum mass applies. '75 kg' is a quick-prep rule of thumb, not a book limit
No. 'may not be less than 1%' is a minimum, not a maximum. At 1,200 kg TMM the nose weight must therefore be at least 12 kg; more is always allowed
No. The text literally refers to 'the load under the coupling of a centre-axle trailer'. This atom is limited to that type
No. The 50 kg maximum applies specifically to a centre-axle trailer WITH A MASS OF AT MOST 750 KG. Above 750 kg it is not 50 kg but the 1% minimum that applies