Question for the smarts on trailers

Cuttlefish:

cav551:

https://www.gov.uk/government/publications/hgv-maximum-weights/hgv-maximum-weights:
38000kg if the combination consists of a 2 axle tractor unit and 2 axle semi trailer where the gross weight of the tractor unit does not exceed 18000kg and the gross weight of the semi trailer does not exceed 20000kg. The drive axle must be fitted with twin tyres and road friendly suspension and the trailer axle spacing February 2010 must be at least 1.8m.

How is the gross weight of the trailer going to not exceed 20,000kg and achieve a combination weight of 38,000kg unless the unit weighs a bit under 18,000 kg unladen? This should read “the Total Axle Weights of the trailer do not exceed 20,000kg.”

Correct, it doesn’t match the regulation

https://www.legislation.gov.uk/uksi/1998/3111/schedule/2/made:
4. Articulated vehicle satisfying the conditions specified in sub-paragraph (3) 4 38000

(3) The conditions referred to in item 4 of Table 3 are that–
(a)the combination consists of a 2-axle tractor unit and a 2-axle semi-trailer;
(b)the weight of the tractor unit comprised in the combination does not exceed 18000 kg;
(c)the sum of the axle weights of the semi-trailer does not exceed 20000 kg; and
(d)the driving axle is fitted with twin tyres and road friendly suspension.

And (b) should probably specify gross weight (even though 18t is the max for 2 axles).

It’s clear enough that it means 38t gcw with 18t max gross on the unit.
The idea of 38t on 4 axles is a joke in itself.From being an ideal road smasher to a braking/jacknife accident waiting to happen.
Even the spread axle makes no sense when a 2 + 2 drawbar is limited to 36t.