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Re: torque


'cause think about it, (remembering torque is Force). how much force does it take to
spin a wheel off the ground - Very Little!  and how much force does it take to _not_
spin a wheel on the ground - None.  so the diff has equalized the torque to a
minimal amount.

yet another way to think about it - if you could somehow put a torque wrench needle
on each wheel:

in the 'wheel off the ground' example, you'd naturally show a very small reading on
both wheels - one spinning, the other not.  as previously stated - an open diff
equalizes torque.

when you locked the diff, the traction wheel would suddenly show huge torque as the
car crashed forward off the jack.  the wheel in the air would show none (until it
hit the ground of course). so... a torque is applied where ever there is traction.

2 paradigm shifts behind why it might be hard to understand this:
     1. you have to unlink RPM's and force. no relationship.
     2. since a locked diff is a something of a 'passive system' it's hard to think
of torque as being shifted or transferred.  the torque shifts, although the diff
isn't taking any action to do so.  just semantics that might be getting in the way.

auditude wrote:

> So, torque exists only when there is resistance to the energy?  Like, there is
> very little torque applied to a wheel spinning "freely" at 10 rpm, but there is
> lots of torque applied to a wheel spinning at the moment it's turning at 10
> rpm that is propelling a heavy car from a standstill?
> This is different than the rotational speed (or is that velocity), because there
> are different amounts of energy required to achieve the same rpm?
> So the discussion is the basically about concepts like a differential locking
> the two outputs so that they are rotating at the same speed (one type of
> locking?), and a diff applying equal amounts of torque to both outputs,
> independent of the output shafts rpms (with the two shafts having different
> rpms, but the same share of the total torque)?
> Am I close or clueless?
> Ken



John J Cunningham III           Project Leader / Technical Analyst
                                             Country Home Products
johnc@together.net                            (802) 877-1201 X1242