I think bil och slap could be 55` when the dragbil och trailer was only 33 `total , but some ran with moms at 60`
later it was legal 60` total when so called `articulated` (dragbil och trailer) was only 35` total , also weights, the `artic ` was total of 24 ton `gross train weight ` up to the 1964/5 regs , but the so called drawbar combination (bil och slap) was allowed 32 ton even in the old days , so you can see Englands ministry of transport did not want `artics ` to become popular , as they used to `jacknife ` under braking and get stuck in the snow and ice because never enough weight on the drive axel , but the three and four axel `ridgid` were mostly double drive and did not get stuck or jacknife and could transport 22 ton loads legally , many many carried much more , but the drawbar had by law to have a crew of two , a driver and his `trailer boy` , from 14 or 15 years old they helped the driver to load , unload , sheet and rope , change wheels and even drove the rig when the driver had a sleep
, a good way to learn the art of truck driving ! , artics took over when extra trailers let the dragbil just change trailers and go , but a two axel bil och two axel slap used less fuel and tyres ,needed less road space on corners , had more load space and was safer and the requirement for the `second man ` had been dropped , MVH Alan.