Re: Stock 16v Sways

[Domenic Lippolis <domlipps@mail2.nai.net>]

At 02:10 AM 2/18/97 -0600, you wrote:
>
>
>On Tue, 18 Feb 1997 GIMPYvwMtb@aol.com wrote:
>
>> Actualy A hollow bar is is actually stronger then a solid
>> bar.....Scientifacly speaking..

        Right and wrong.  If you are talking the same size bar yes, but a
solid bar is not that much stronger and as I said before it depends on the
wall thickness of the bar (see below.)

>
>I don't think this is true. It is true that a hollow bar of larger 
>diameter is stronger than a solid bar of smaller diameter --the savings 
>there come in terms of less material used for the construction of the 
>hollow bar. But if you have the same diameter hollow and solid bars, then 
>the solid bar should be stronger. 
>
>I'm not 100% sure of this, so I would love someone to come out and 
>responsibly state the scientific truth.
>
>
>Ilias

        The majority of the torsional stress is found at the outer diameters
of a bar, as you proceed to the center portions (the inner diameters) the
stress becomes less and less. 
                         ------------------------------
   High Stress->  |                            |           
   No Stress   ->  |        BAR             |
   High Stress->  |                            |
                         ------------------------------
 At the center of a bar the stress is zero.  (For a straight bar, that is)
The same holds true for springs (a torsion bar wound into a helix) but the
stresses are greater inner diameter of a spring:
                                        
                                 /     /  
                                (     (<- More stress
                                 \     \
        (Its is hard to draw a coil using ASCII)

Those who want to do the math:

        Stress=Torsional Force X Length of Rod
                    -----------------------------------------------
                       K'  X  Torsional Modulus of Elasticity

        K' =   Pi                               4                            4
                ----- X  ( (outer diameter)     -  (inner diameter)   )
                32  
                        For english Units.

					DOM!
					1980 VW Scirocco S
					1983 Alfa Romeo GTV-6
					1986 Kawasaki 600 Ninja
					1979 Piaggio Vespa P125X

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