Adjustable Strut Rods
Is there value in adding shims to tighten the gap between the spring clip and the torsion bar?
Also, do you know of any poly strut rod bushing that are the correct thickness and locate the wheel side of the LCA in the correct location? Seems like if one would want to run poly strut rod bushings, they'd either have to modify the bushing, or use adjustable strut rods.
No, I don’t believe there’s any value in adding shims there. The torsion bars are captured, they can’t fall out. Some movement of the bar back and forth as the suspension works is inevitable, as it loads and unloads it also will lengthen and contract some. That’s a very small amount, but you wouldn’t want to completely prevent the bar from moving in those directions. Shim it tight enough and you might even break stuff. And they aren’t there to locate the LCA, that’s not their purpose.
As for the poly strut rod bushings, I don’t think any of the manufacturers really nailed the thickness. And just like adding the poly or Delrin LCA bushings, the thickness of the bushing becomes more critical because there’s less give in the material. So being a little bit off on thickness doesn’t just compress the bushing more, it starts moving parts.
The other thing is that the strut rod bushings have to allow for the up and down movement of the LCA. The poly is good because it limits the fore/aft movement, but it’s also
bad because it will also limit the up and down travel, it will resist that movement and make binding more of an issue at the extremes of LCA travel. That’s why the adjustable strut rods are great, they limit the fore/aft movement of the LCA that you DON’T want AND make the up/down travel even easier/smoother.
Most of what I said you just repeated. I agree the adjustable strut locates the arm, that's how I did it too. I agree the torsion bar clips do not hold the arm and that they usually do not even touch the torsion bar. Whenever I have removed a torsion bar I have always found the best way to get all the tension off is unbolt the upper ball joint so the arm can drop even lower.
My point is that the torsion bar imho works as part of a system along with the strut to keep the arm on the pin. Those bars cannot slide back easily at all even when partially unloaded.
I am not trying to get into a heated debate with the two of you.
I am just saying that I think both of you were partially right in different areas. But that is just my opinion.
Stay healthy my friend.
I see your point, yes, when the bars are loaded they aren’t moving.
But the bars do move. They expand and contract as they’re loaded and unloaded. Really small amounts, but they move. And if the bars fully unload they can slide. With stock torsion bars that’s not much of an issue, but with larger aftermarket bars that have less offset it’s not uncommon to completely unload the bar at full extension. I have to run taller upper bumpstops to keep my adjusters loaded at full extension.
But here’s the thing, from an engineering perspective that means you can’t ever assume the bars will limit the back movement of the LCA. Even a small shift in position could change that effect. And fully unloading the suspension does. I’ve pulled torsion bars out by hand when they were unloaded, and as I’ve said before that doesn’t require the LCA to be detached depending on how your suspension is set up.
Basically if you can’t ALWAYS depend on the bars to hold the LCA from traveling, then you can’t design the suspension to depend on them at all.
