Let's sift through every square inch of a 2013 Tahoe PPV

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iamdub

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What's interesting about the GMT360 rear bars is that they aren't very straight... Meaning, the bar can't really be very parallel. The end links are also pretty awkward.

I have one of these hanging from the rear axle of my 94 Fleetwood from zip ties. I'm playing around with a bracket kit, because those cars don't have an axle/frame mounted rear bar.

In my recent sway bar research in trying to come up with a solution for my end links, a buddy (mechanical engineer, builds crawlers and overlanders, etc.) told me he read somewhere that the bar is optimal at an angle of around 15°. But, he's an off-road guy so this might've been related to that, maybe for better articulation. Considering this, how well it works as-is and after looking at my bar's angle, I'm now not as concerned about flattening it as I am about fixing the funky end link angles.
 
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Caddylack

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Okay, let's say that instead of shortening the end links, we just make them more rigid.

I noticed that Hotckis end links are much thicker than OEM, as far as the rod/shaft portion. I feel like the bushings would be the best way to stiffen things up.

What about an end link with a heim joint at the frame end, and an OEM-style poly bushing at the bar? Combined with a thicker rod/shaft.
 

iamdub

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Okay, let's say that instead of shortening the end links, we just make them more rigid.

I noticed that Hotckis end links are much thicker than OEM, as far as the rod/shaft portion. I feel like the bushings would be the best way to stiffen things up.

What about an end link with a heim joint at the frame end, and an OEM-style poly bushing at the bar? Combined with a thicker rod/shaft.

If the links are straight up and down, or, at least linear to the movement of the bar, then they'd be in tension and compression versus shear. A metal rod is much stronger in tension or compression than in shear, so it can be smaller or hollow, as the factory ones are. Hotchkis's links are adjustable, so they're gonna be huge since it's a threaded rod going inside a threaded boss. Also, many aftermarket performance parts tend to excessively, even unnecessarily bulky to emphasize their "heavy duty/performance" aspect. They wouldn't want customers feeling they got a weak and inferior product for the big bucks they dropped, right?

Massive, He-Man links just aren't as necessary as we'd think. Take the rear links for my relocated sway bar, for example. They're offset, so the rod in between and their welded joints are surely under a lot of shear loads, especially with my driving. The rod itself appears spindly and weak, never mind the two bends in it. Surprisingly, I see no indication of failure- yet. I would not be the least bit disappointed if one bent or snapped one day.

You're right- the bushings are what deflect the most while in action. Rubber, polyurethane, thermoplastic, etc. will all deflect long before the solid steel parts. But, you need some sort of cushioning since metal-on-metal is harsh and can be noisy.

for an adjustable link, I like the idea of a Heim and bushed link for the rear. My response to that is that the adjustability, in general, is just not needed. How often are you adjusting your link length? It's the same as why I wouldn't buy or build fully adjustable trailing arms. Once you get the rear end where you want it, you're done. All the extra expense in having the adjustability is now spent. I plan to get new lower arms and lengthen them to put the rear end where I want it. I'll make adjustable uppers to match the length and set the pinion angle. Even then, the uppers will be simple, requiring the link to be unbolted on that one end, screwed in or out as needed, then bolted back in place. No need for the double threaded stud setup like the adjustable panhard is. Lower arms will be stock rubber bushings, uppers will be poly. I think Hotchkis made adjustable links as a way to complement their adjustable bar leverage and to fit a range of ride heights, since all of that affects the mounting point distances. As for the beefiness, it's appreciated, but not required.

I don't think there's enough lost movement in the end links to worry with striving for solid bushings (Heims). I think poly is plenty sufficient for a daily driven street car. Heims would wear and become noisy, requiring maintenance. It's creating a maintenance point where you'd never see any benefit.
 
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Caddylack

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I'm probably overemphasizing the end links being skinny, but it just blows my mind that they could do much of anything with the vehicle being so heavy.

I don't care much about adjustability, I'm just uncertain of the correct balance between bar stiffness and end link stiffness. Like you said, the same sway bars are used on all GMT900 models, regardless of ride height or anything else. There is surely some margin for error, and it's unlikely that GM spent any more time on it after declaring the setup "good enough".

I like the front end links from Spohn that are spherical on one end.
 

iamdub

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I'm probably overemphasizing the end links being skinny, but it just blows my mind that they could do much of anything with the vehicle being so heavy.

I agree. The stock tube style links looks stronger than the DJM links I have now. I thought for sure I'd break one by now.


I like the front end links from Spohn that are spherical on one end.

Googling...
 

iamdub

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It's a mod that I am familiar with from the full-frame cars. I know Spohn makes the same thing for B, G, and F bodies, among others.

You tease. I was looking all over their site for such links that could be adapted to the mounting style we have in the front.

*EDIT* I found them in the F body section. I see what they have. It's like a bar pin eliminator for shocks. $90 for the pair. If they could fit in the space allowed, they'd be an easy bolt-in solution.
 

iamdub

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Yup. That be's them. I was looking at the SEL-19-406 since they appeared to be the shortest they offered.

But then I referred back to my pic and decided that I just don't have enough space for links- period.

IMG_E4158.JPG


Maybe I should look for a big ol' donut bushing, some fender washers, and a 4" bolt and let the donut bushing provide whatever flex it may. It'd probably feel like I solid axle swapped it.
 
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