Very interesting discussion guys, thank you. .. all I know is that I can use the D538 crane to pick up all 4 short logs then haul them back to the road to put them on the bed of a 65110 on street tyres, thus giving me another haulage option on The Ridge... (I managed to One-star the map too. )
I just get used to having to shove the 538 into low range and wait for the wheels to start turning - there's no instant throttle response on an incline