OK - so Torsional stiffness Torque/Rotation = KG/L where K = Pi/2
x (Radius)4 ---- (Thats radius to 4th power or squared twice -
cant seem to make superscripts work) and G is a constant for steel
and Rotation is in radians.
But all you want to know is difference in stiffness, so take G as
a constant and just look at difference in R4th/L
And since L is constant here at 40 in, difference in stiffness is
simply (.505)4 / (.495)4 or 1.08329 - translated 8.3% difference
in stiffness between 300 Sport (or Newport Sedan / Conv, etc.) at
0.99 and H at 1.01
H vs New Yorker 12.8% stiffer
H vs Newport wagon 17.5% stiffer
And by the way, to convert to stiffness you need distance from
center of rod to centerline of tire - if you want absolutes, need
to go thru more calcs incl dealing with G Shear Modulus and
radians.
But unless you are playing with different wheel offsets (going to
aftermarket wheels - moving out increases moment arm and increases
torsion which effectively "softens" car spring rate - moving in
effectively "stiffens" but you get interference) or changing hub
dimensions (such as may be if changing to disc brakes, etc).
PS - If you are also playing with Anti-sway bars on front only,
it would not be unusual to soften spring rate if increasing sway
bar stiffness on that end - otherwise you would need to play with
back of car to keep handling balance (oversteer / understeer).
For example, if you add a rear sway bar to a car that did not
originally have one, and you do nothing else (no change to rear
spring rate or better front bar increase in stiffness to balance
handling), be prepared for rear end to come around fast in a hard
turn - potentially severe oversteer condition. (Personal
experience, lesson learned)
Edward Mills
Antique Tractors 1930-1960
Antique Cars 1960-1985
On 6/20/2016 1:45 PM, 'Rich Barber'
c300@xxxxxxx [Chrysler300] wrote:
HD
suspension may have been an option on all ’62
Chryslers and included the thicker torsion bars which
were standard on the H.
Rich
Barber
Brentwood,
CA
Newport Sedan, hardtop,
convertible: torsion bar 40.0" x .99" diameter
Newport station wagon:
torsion bar 40.0" x .97" diameter
Sport 300: torsion bar 40.0"
x .99" diameter
300H: torsion bar 40.0" x
1.01" diameter
New Yorker: torsion bar 40.0"
x .98" diameter
------ Original Message
------
Sent: 6/20/2016 1:12:32 PM
Subject: RE: [Chrysler300]
Strut / Torsion bars
To
my knowledge the strut rods do not
flex or bend or twist at all, they
just move a bit in the rubber, to
allow the suspension to move up and
down , while locating suspension
arm / spindle fore and aft. so that
thickness is a non issue. (axial
loads only); rubber durometer might
change that fore and aft stiffness
but not much and only of value for
that kind of (rare) loads? —in case
you hit a very deep pothole. ; I do
not understand the torsion bars at
all. It should be the other way
around., stock ? The 300 should be
thicker, as that is (factory)
stiffer ; maybe 300 were swapped to
smaller in the past? Any chance
those numbers are inverted? Or 300
sport was really a very soft car
compared to 300H ; which may be
true. Interesting info, that is for
sure.
But
I do not know the factory 300H
specs. Others will…
Why
would a Newport be sprung stiffer
than a sport?
See
listings of aftermarket / MOPAR
performance torsion bars for B and E
bodies, as a rough reference?
Thicker bars = stiffer suspension ,
mostly, usually related to holding
up heavier engines too. . Might or
might not like that impact on ride .
( I like stiffer) but------Not like
it is a race car, screaming around
corners on a NASCAR track? IMHO
Hi Group,
Last year
I installed a factory sway bar on my
62 Sport. In discussion with Dave
Dumais at the MaCunngie meet, he
said that it was likely that the
strut rods on the doner (Newport)
car were likely larger dia. Upon
inspection, I found that this was
indeed true. My current strut rods
measure approx. .015 smaller than
the Newport.
Also, a
measurement of the torsion bars also
reveals a difference. My Sport
measures approx. 970 dia. and the
Newport at approx 1.010 dia.
So the
question is - Would it be worthwhile
to swap out these parts to my Sport.
I guess I'm wondering what
difference, if any, would I notice
in ride quality / handling.
Thanks,
Charlie in Ottawa
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