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Re: [TR] Considering tube shock conversion for 4A

To: tr3driver@comcast.net, triumphs@autox.team.net
Subject: Re: [TR] Considering tube shock conversion for 4A
From: Dave1massey@cs.com
Date: Sat, 6 May 2006 19:09:37 EDT
In a message dated 5/5/2006 4:45:47 PM Central Standard Time, 
tr3driver@comcast.net writes: 
> >I haven't thought about it much seriously but since the two end
> >points are
> >the same it should lead the frame the same.
> 
> Are they the same ?  That's a serious question, I don't know the answer.
> But if the upper attachment point is radially farther from the original
> shock mount than the lever shock link attachment, then there will be more
> (twisting) force applied to the shock mount even for the same shock
> resistance &rate of travel.  The twisting at the shock mount is the force
> at the link attachment, times the length of the lever arm.
> 
> And since I think the tube shocks are far longer than the original link, the
> attachment point probably is farther from the mount.
> 
> 

Good point.  I guess this would be called non-tangential forces that would be 
applying either for/aft of sideways force on the suspension bushings instead 
of used to dampen movements of the suspension.  Ref the angled shocks typical 
of solid axle trucks and vans from the 60's and 70's.  When Ford brought out 
its Fox chassis (Fairmont/Mustang) it set the shocks straight vertical.  The 
car mags at the time said that setting them at an angle was thought to improve 
stability but this mindset was proved wrong (I don't recall if they explained 
why but it makes sense to me)

But the tube conversion on my car has the shocks mounted quite close to the 
same angle as the shock link on the levers in the original setup.  This would 
minimize non-tangential forces and ever reduce them with respect to the lever 
shocks since the shock links angle will depart from the vertical as they move 
through their own arc.

The force applied to the shock mount is a function of the force applied to 
the trailing arm since there are no other forces applied inbetween.

Increased damping forces not with standing.

Dave


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