Heavy Rob Knob

[David Beatty <dbeatty@xxxxxxxxxxxxxxxxxxx>]

My, that knob would look good in my //m...  Caveat, I haven't had a
physics course in almost 10 years, and the last ones were subatomic
physics.

It is difficult to predict why the knob shifts with less effort without
evaluating the overall set up.  It is likely due to several aspects,
each of which may have different degrees of influence.

First reason:  It is easier to shift because of the increased leverage
advantage.  Gravitationally induced leverage force is proportional to
both the horizontal length of the lever and the mass on the lever.
Greatest effect is experienced as the knob approaches horizontal.
Notably, an equivalent increase in effort will be required to remove the
shifter from a gear, but this effect is not noticeable because of the
relatively low effort required for such a maneuver as compared to the
gear entry maneuver.

Second reason:  Assuming the operator throws the shifter at the same
speed as with a lighter knob, the greater inertia assists in entering
the gear at the end of the throw.  Notably, this inertial effect will,
on the other hand, require greater effort to remove the shifter from a
gear, but this effect is less noticeable because of the relatively low
effort required for such a maneuver as compared to the gear entry
maneuver.  In effect, the heavier knob provides better energy
management.  The inertial effect also contributes to an overall feeling
of stability by diminishing rebound.  

Third reason:  Psychological.  The knob gives a better shift feel
because, being a larger mass, it better absorbs the vibrations
transmitted by the shift lever, thereby reducing the transmission of
these vibrations to the operator's hand.  The vibrations of concern are
those emanating from the impact in the linkage as the shifter attempts
to enter the gear and encounters resistance.  
Because less vibration is experienced by the operator, it feels as if
the knob is going in with less effort.  

Fourth reason:  Rationalization.  The knob looks so cool you have to
have it.  However, in order to justify to yourself or to convince others
(aka spouse) that the knob functionally improves your car (and is
therefore not analogous to the jewelry/HDTV she/he wants), you imagine
that it improves the shift procedure.  This would explain why the
titanium model shifts better than the aluminum model, notwithstanding
the lower weight of the titanium.  

OK, best I can do and still put in 12 hours on the clock.

(For the record, my wife does not like jewelry and insisted we get the
//m roadster.)

David D. Beatty
Myers Bigel Sibley & Sajovec, P.A.
Patent Attorneys
Suite 250, 111 Corning Road, Cary, NC 27511
PO Box 37428, Raleigh, NC 27627
Telephone: 919-854-1400
Fax: 919-854-1401 
dbeatty@domain.elided
web site: www.carolinapatents.com 

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