Offroad Trailblazers and Envoys

Upgrading the Tie Rods

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by AlekG » Fri Apr 02, 2021 3:04 am

OK, so here's a preview of one of the projects I am currently working on:
Heavy duty tie rod upgrade using the PPE (Pacific Performance Engineering) GM 2001-2010 Stage 3 Forged Tie Rods.

I actually started researching this and bought them back in 2017 but of course ran into issues. Here's the quick background:
In my research I found that the overall length was in our range, the inner thread (16mm) was correct and the outer ball joint post dimensions were almost exact. (Note that some early vehicles had 14mm threads). If needed, the forged piece could be shortened to make it work (in the PPE instructions). In my tunnel-vision with the measurements though, I overlooked/forgot that our inner tie rod recedes into the rack! :facepalm: :oops: So of course when I had the brake overhaul done and wanted these installed, my mechanic looked at me like I was crazy.

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I didn't want to abandon the project so since then I have been periodically working on a potential solution. Mainly it will require fabbing up a 2 inch solid piece of metal that mimics the inside (thickest) part of the inner tie rod (where the ball is). With 16 mm male threads on one end and 16mm female threading on the other. This 2 inch piece will recede into the rack keeping the PPE oversized inner ball joint outside of the rack.

This will then require a shortening of the forged piece by 2 inches (probably a bit more to allow for adjustability) and drilling out and extending the thread inside the forged piece by 2+ inches. Once all that is done, I am hoping that this solution will keep tie rod failures to almost zero.

Another piece of the puzzle will be the boot. I bought some aftermarket more flexible ones (Duralast) for testing. It works on the outer end because it is flexible enough to push the smaller hole onto the forged piece. The inner end is the problem. Even though the oversized ball joint can fit inside the boot, it touches the boot and will cause resistance and binding which will not work. So I am searching for a supplier that carries various sizes of industrial machinery boots. I will need to find one where the outer ends match the rack and PPE ODs, and the middle bellows ID is large enough to house the oversized ball joint with no resistance.

And lastly, I did some calculations based on stock angles, lengths, etc. The stock tie rod setup allows for a maximum angle of about 32 degrees (tested on steering rack from auto yard), although I don't think we ever reach that even at full droop. By adding the 2 inch adapter piece which pushes the pivot point (where the ball is) out by about 1.75 inches, the PPE ball joint will need about 37 degrees to reach the same droop as the stock tie rods. I think the PPE tie rods can handle this, but I do currently have an email into their tech dept. to confirm what their maximum angle is. Again, I don't think our vehicles get to that maximum angle but it is necessary to know so that if needed, limiter straps would be installed like I have in the rear.

I put together a rough diagram showing the angle and length differences between stock and modified PPE. All measurements are approximate.

Image

I have a line on a local metal working shop that claims reasonable pricing. Some of the examples on their web site are small, custom, one-off projects so I believe this could be right up their alley.

Will update when things progress ...



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AlekG
Off-Roader
 
Posts: 112
Joined: Tue Sep 15, 2009 9:29 pm
Location: Guelph, Ontario, CANADA
Name: Alek
Vehicle Year: 2006
Vehicle: Chevrolet TrailBlazer
DriveTrain: 4WD w/ Aftermarket Locker
Rank: Expedition Rated

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