Question about Torque

[RSmith]

Simple but probably silly... I was told that torque is multiplied by the gear ratios and final drive of a powertrain. Is this true?

If so, if a car has peak torque of 100 lb/ft with 1st gear ratio 3.6 and final drive 3.1, does that mean in 1st gear at full throttle there will be 1,116 lb/ft torque being split to the rear wheels?? That can't be right, surely?! (100 x 3.6 x 3.1 = 1116)

Can anybody shed some light on this?

 

[HDi fun]

It is right!

 

[RSmith]

This then leads me on to another question related to this... if this is the case then how can series hybrid vehicles (that store electrical energy from an engine and then power in-wheel motors) have enough power to go? Surely the power's just being collected and not multiplied by gear sets?

 

[HDi fun]

Electric motors have very different torque characteristics to internal combustion engines. The operating rev range is adequate to go between standstill and say 120mph without the need for different gear ratios, though quite often the in wheel motors operate through a fixed reduction gear.