Why Do These TRUCKS Have Too Many Axles And Tires? ▶Advanced Trucks and Machinery 

they put them on "backwards" for better braking action, so under braking the tyre will dig-in and clear dirt, gravel, mud etc to the sides rather than the tyre riding-up on he dirt etc under braking if the haul-roads are dirt etc, this is also why agricultural tyres with a chevron type tread when placed on trailers or other trailed appliances are often reversed in direction relative to the tractors tyres, to get better braking effect. if they have hills they have to go down loaded, or the ground is hard rock this will encourage the trend of doing so, the latter due to reducing wear on hard surfaces too in addition to better braking action. this is also similar to why some farm tractor with loaders and some wheel loaders and backhoe with tractor like chevron pattern tyres have the front tyres on backwards, so the get better traction in reverse when backing away from a pile, and going forwards the driven front axle will climb out of wheel-ruts much better.

@@b101uk9 Thank you, that's really interesting. On something with 2 wheels side-by-side, does anyone put the tires in both directions?