Does the weight of a car or length of gears it has change the requirements for clutch strength or is the requirement solely dependent on the torque the engine applies to it? I see a lot of consensus that says the former, but I think it is the latter. An engine making 300 lb-ft should need a clutch that holds 300 lb-ft regardless if its hauling a 150kg motorcycle or a 5000kg truck. The gear or mass that applies resistance shouldn't change anything because it isn't a counter-acting torque. I believe a stronger clutch is required than the engine when there is a counter-acting torque applied such as if a vehicle is going on an upward incline (a hill). Now, the question from this of course is why do cars tend to have slipping clutches in higher gears first. I believe the answer to that is acceleration. A higher gear means less acceleration so less power diverted to spooling up the rotating masses of the engine internals and flywheel and more of it moving through the clutch, right? In a low gear with a lot of acceleration, a bunch of power is sucked up spooling up the crankshaft and flywheel which reduces torque seen by the clutch. That is why it appears the load is what is causing the slip as opposed to less power (and therefore torque) left over to spin the clutch. Am I entirely wrong? Would an equivalent engine really require a stronger clutch in a higher load situation?