The double rear axels are not just there for aesthetics, there are two types and both are fully working, the 6x2 has two rear axels one is driven but the other which has two wheels the same as the front wheels, steer, do an outside view of a 6x2 and turn the steering wheel and you will see. The other double rear axel is the 6x4, on this both rear axels are driven and both sets of wheels look the same, it gives you more pulling power.