Torque Steer after replacing Driveshaft?!!!

**string** · 07-10-2010 09:40 PM

Originally Posted by Lukey

fwd's will always torque steer to the side which has a longer shaft?

and what do you mean 'winding up'??

The usual claim is that a longer driveshaft "flexes" somehow contributing to different torque at the tyre.

If there were any truth to this, then, like a spring, it will reach maximum deflection after a given ammount of time and then remain deflected until the torque is removed. The time constant of an imbalance caused by this mechanism would be TINY.

**Lukey** · 07-10-2010 09:43 PM

ahk. but ive noticed my dc4 also torque steers to the left a bit.

thats what i was taught in tradeschool, that the car will torque steer to the side with the longer drive shafts, even if they are the same lengths, but with the intermediate shaft (i hope that made sense to you?)

**newpaddy3** · 07-10-2010 09:44 PM

I was of the belief that it was due to inertia

**string** · 07-10-2010 09:50 PM

Originally Posted by newpaddy3

I was of the belief that it was due to inertia

An open differential will apply 50/50 torque. If one side has a greater rotational mass then indeed the tyre will see less of the torque.

Unfortunately for such an argument, the radius of the driveshaft is about 0.5cm so the moment of inertia would be microscopic relative to the wheel and tyre. Then consider that we are only interested in the DIFFERENCE between the moments of inertia of the two driveshafts. I doubt such a difference would consume even a millionth of the mechanical energy.

**Lukey** · 07-10-2010 09:54 PM

this conversation has gotten way out of my vocabulary. i shall now exit the thread.

**string** · 07-10-2010 10:00 PM

The OP already indicates a left/right suspension imbalance. Old bushings don't like to be mucked with. The rubber developes a memory and likes to keep deforming the same way so it's critical to keep them happy, otherwise they will deform or tear and further throw out your L/R balance which is where torque steer thrives.

The mechanism for torque steer is identical to that of steering pull under braking. Scrub radius or longitidinal force - if they're not equal left/right, it's going to pull.