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

To: <spamiam@comcast.net>, "Triumphs List" <triumphs@autox.team.net>
Subject: RE: [TR] Considering tube shock conversion for 4A
From: "Randall" <tr3driver@comcast.net>
Date: Fri, 5 May 2006 06:35:05 -0700
> 1)  The conversion which bolts the upper end of the shock to the inner fender.

Suspension forces transmitted to the body ... Run Away, Run Away !

> I saw something on the internet saying that this off-center
> torque will make the frame fail.  DOes this actually happen in real
> usage?

I've heard of it happening, although I'm not sure it's from hitting the stop.

>  I would think that maximum downward travel would be relatively rare.

Depends a lot on how you drive.  On my TR3A, I had to change the rebound stops
every few years, because they wore out.  And even on the Stag, which has a rear
suspension more like the TR4A than the TR3A does, it's easy to get one rear
wheel in the air, meaning the shock is topped out.  I'd say that was my biggest
limiting factor at the autoX at Rockford, keeping the inside rear wheel planted
well enough to get power to the ground.

And if you don't plan to drive it hard, why upgrade ?

> The, the torque from the off-center upward force is probably much the
> same for both the original lever arm and #2, but I have not analysed
> the geomotry of #2 since I have not seen one personally.

I believe there are actually several different varieties of #2 around, but I
don't know which one TRF sells.  Among other things, they vary in how much they
reduce tire clearance, so this might be a concern if you plan to upgrade the
tires too.  That probably means the geometry varies, too.

But even with the same geometry, the usual point of converting to tube shocks is
to use a much stiffer shock than the stock ones, which means more force
transmitted to the shock mount.

BTW, the lever shocks are adjustable in both directions (Spax and Koni only
adjust one way) and if in good condition can be valved almost as stiff as you
want.  And they last a lot longer.

> P.S.  I think I might go with the Moss blue-yellow 420lb (stock ride
> height) springs front and back, with spax (hopefully externally
> adjustable) shocks up front.  I also hope to have some sort of
> adjustable shock in the rear too.  Also thinking about 7/8" front
> sway bar.  Debating abot the rear right now.

What did your fillings ever do to you ?
;)

Randall


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