Re: Re: anti-wrap via radius arms (was RE: JPOR: Bigger lift options.)

["Ed Tapanes" <EdTapanes@xxxxxxxxxxxxx>]

Lars,

OHH!  Okay, now I understand.
The ASCII art helped alot (especially when seen with a non-proportional
font).  Don't underestimate you're 'splaining abilities, you learnt me real
good.:-)

Seems like while that method allows for a better angle, it would increase
the forces working on that arm as well?  I mean wouldn't it almost be
working as a panhard bar as well?

Thanks,
Ed T.

- ----- Original Message -----
From: Larry Soo <lars@bc4x4.com>
To: Ed Tapanes <edtapanes@earthlink.net>
Cc: <jeepoffroad@4x4wire.com>
Sent: Friday, February 25, 2000 12:10 AM
Subject: RE: Re: anti-wrap via radius arms (was RE: JPOR: Bigger lift
options.)


> ****************Please Remember to snip your replies***************
> Ed, I'm cc'ing this to the Joffroad list since I'd like to get others'
> opinions on this...plus I want to get as much mileage as I can from the
> ASCII "art" I made.
>
> At 05:16 PM 2000-02-24 , you wrote:
>
> >Okay, now I'm _really_ confused. :-)
>
> Then I'm probably the last person you should turn to for an explanation.
<g>
>
> >Since the radius arm (unlike a 3 or 4 link system) will keep
> >the axle housing from rotating in relation to the arm, it will
> >change the pinion angle (in relation to the t-case yoke) upon
> >compression/droop.  So the only advantages I see by duplicating
> >the arc/movement described by the driveshaft are that if you're
> >running a CV joint at the t-case side of the driveshaft, the
> >pinion angle will remain neutral throughout the travel of the
> >axle.
>
> I'm running a CV joint.  If you want to keep the angle the same at all
> times, then you're looking at some kind of parallelogram type of setup,
> like a 3- or 5-link.  And even then, the arm placement is critical: the
> vertical & horizontal distance between the two links' (assuming four links
> and a panhard rod, when I talk about "the two links," I mean the left pair
> or the right pair) frame mounts need to be the same as their axle end
> mounts'.  Some difference is ok since the resulting change in pinion angle
> might be neglible for our purposes.
>
> >Additionally by locating it as close as possible to the
> >center of the axle housing, you also reduce the amount of total
> >travel necessary for the arm.
>
> Yes, you're right.
>
> >Is there another reason that I'm
> >missing?
>
> I think so.
>
> Top view of axle:
>
> w = wheels
> t = axle tube
> D = diff
> R = radius arm mounted to axle
> r = radius arm
> f = radius arm mounted to frame
>
>                f
> w              r  w
> w             ar  w
> wttttttttDtttttRttw
> w                 w
> w                 w
>
> In this example, the angle, "a", is 90 degrees to the axle tube, measured
> against the horizontal plane.
>
> Now, when the right hand wheel droops, the radius arm must continue to
> point at "f", the frame mount.
>
> Angle "a" can no longer be 90 degrees because the axle is no longer
> parallel to the ground.  Hence, the radius arm needs to be able to twist
so
> it can continue to attach to the frame.
>
>             f
> w            r    w
> w            ar   w
> wttttttttDtttttRttw
> w                 w
> w                 w
>
> In this example, we attach the arm so that angle "a" is more acute and
lets
> the frame end of the radius arm to attach closer to the center of the
> vehicle.  Now, when the right side droops, angle "a" can stay closer to
its
> original value because the distance between radius arm mounts "f" and "R"
> stays relatively consistent.
>
> Does that make sense to you?
>
> Now, I don't know how important this is.  All I know is that it should
> reduce the amount of lateral bending required of the arm.  That, in turn,
> should result in less resistance to articulation.  But whether or not
we're
> talking about amounts that we will notice, well, I can't answer that.
>
>
> ...lars
>
> http://www.bc4x4.com Canada's biggest 4x4 site
>
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