4.5 tonne Canter. I have an old Toyota Coaster scissor jack (geared) for when there's not much space, and an 8 tonne hydraulic bottle jack. I don't believe the rating. I find the constraint is not how much load the jack will take but how long the handle is and how hard I have to press to make it work - flimsy short handles and difficult to locate release screw are a pain. And of course the heavier the jack the harder it is to locate under the truck. I've forgotten how much lift I needed to get from totally flat tyre to totally inflated. Every so often I try to find a two stage hydraulic jack, and a low profile screw jack. Apart from the obvious changing wheels I most recently used them between axle and chassis while making temporary fix to broken spring. Later changing spring bushes/shackles. The low profile scissor jack is particularly useful for many things, sadly has least leverage when fully down. IMHO screw is less likely to fail than hydraulic. I haven't had hydraulic fail catastrophically, just leak and become progressively less useful - replace rather than refill.
I avoid high lift jacks. Scary things.
