Why do American semi-trucks (18 wheelers etc) exclusively use inline 6-cylinder engines, no matter if it’s a Mack, Detroit Diesel, Cummins, or Volvo-built engine?

Question

I get why they are diesel, but why are they all of the inline 6-cylinder configuration? Why not V6 or straight 8 or freakin huge inline 4-cylinders?

In: 715

Answer 1

They have a more simple design, less parts, smoother and produce lower end torque that is important in a truck. They pull heavy loads, so the low end torque allows them to get up and running without having to wind out the engine, which means lower maintenance since they don’t have to be beaten into action.