Why do lorries have 8 wheels on their trailers? (pressure related)
Robbers. the hoosier song.dont know why.i don't even like them that much xx
cop -your caught out i have copped you doing wrong yet again a policeman/woman a liverpool ground the Cop
Actually, there is another more practical reason why lorries/trucks have 8 wheels.FLAT TIRES. A vehicle with only 4 tires that suddenly has a blow-out will lose control because the vehicle has become unbalanced and won't handle or steer properly, especially when travelling fast on a highway. If you have 8 wheels, and one blows, you still have 7, which is more than enough to maintain control of the vehicle. So 8 tires are for safety reasons and because its much harder to change a flat on a lorry than a car.
The pressure in the tyres (I'll use the British spelling since we're discussing lorries, and not trucks) needs to support the weight of the vehicle and its cargo. The tyres will deform until the pressure in the tyre multiplied by the size of the contact patch is equal to the weight that the tyre must support. For example, if I have a 1000 lb load, and the tyres are inflated to 30 psi, the contact patch must be 33 in^2. However, if I have 4 tyres at 30 psi, each contact patch is reduced to 8.33 in^2. If I had only 2 tyres, and wanted the same contact patch area, I would need to double the tyre's inflation pressure, increasing the risk of a blow-out. Reducing the contact patch reduces wear on the tyre and increases the efficiency with which the lorry moves. (Deforming those tyres takes energy, which means power robbed from the overall efficiency of the vehicle.)
Basically they have so many wheels to dispurse a lot of weight evenly over a small area. It is to reduce damage on roads, make it possible to go over bridges (they do have weight restrictions), and make it possible to haul more weight (wouldn't want the trailer to snap in half)
