Total Lateral Load Transfer Distribution

[Sleeper68]

A concern is that arm:
https://www.cachassisworks.com/p-295...-aluminum.aspx
being made of aluminum, that type of .2in flex 100% guarantees eventual breakage. It's a matter of time- that said, could be a long time, but at .2inch I don't think it would take long at all. Even 0.040" under much greater (ie active) load would worry me if I were the manufacturer.

I agree, this is another reason I am changing to steel steering arms for this geometry. Aluminum has a finite fatigue life, regardless of loading condition. This being a fully-reversed load, it is virtually worst-case. Steel CAN have an infinite fatigue life if the stress is kept low enough and stress risers are properly addressed.

Now rather than condemn a product, I'm going to go the other way. Are you absolutely sure the arm itself is flexing? It's not within the wheel bearing or even tire carcass?

I am not absolutely sure. Other sources of compliance may exist, certainly. The fact I could watch the distance between the tie rod and the wheel change while moving the steering wheel with the car static, told me alot of this compliance in the steering system was coming from the steering arms. Wheel bearing play could cause this, but I precisely set wheel bearing preload with a bearing spacer and torque wrench. Also, wheel bearings are replaced every season, so I doubt much of the compliance comes from the bearing. This, is in no way, a dig at Chassisworks. I love their products and I do believe they put alot of thought and time into their products. It is, however, my belief that the majority of the compliance is coming from the steering arms.

Where is it flexing? You believe it's bending off the solidly mounted rear spindle bolt? (this is rear steer, right?) That's the only way I could see possible- I see it as solidly mounted, then a cantilever off the rear bolt. You're saying you document that at standstill? Makes no sense. If it were that much of a wet noodle, the first hard corner or hard corner with a bump in it, and it would be gone.

Yes, it appears the steering arm is bending, in two different axes. One axis is the steering axis, but the other, more significant, axis is a horizontal (more or less) line at the rear spindle mounting bolt. One important note: most users of this arm will see less flex than I do because they use it as intended: with a factory tie rod end. I have lowered my outer tie rod end about 0.75" from the factory position to correct bumpsteer, further increasing the cantilever on the arm. 1st gen F and X bodies are rear-steer, yes.

I need to apologize, as I was not clear about where and how the ~0.2" flex was measured.

1. Displacement of the zerk fitting of the outer tie rod end was measured with a dial indicator. No indicator was placed on the wheel.
2. The car was sitting at ride height on concrete floors.
3. ~0.2" (I don't remember the exact number) is the TOTAL displacement displacement of the zerk fitting on the outer tie rod end of one side of the car when turning the wheel both left and right up until visual indication of wheel movement was detected.

This was not a robust test method, nor are these displacement values representative of what may others would experience. The main reason for this is because my outer tie rod end is quite a bit lower than the factory steering geometry, which is what these arms were designed for. So low, in fact, that the wheel has contacted the tie rod when I had my bumpsteer virtually corrected. I had to move the tie rod end up 0.05" to prevent rubbing under hard road loads.

I plan to re-measure this displacement when the car is static with the current setup. I will amend my test method by placing an indicator on both the wheel rim and the tie rod end. Rod end displacement will be recorded in both directions when wheel displacement is 0.010" from straight ahead. The 0.2" number will likely shrink following this procedure. I will also repeat the test 3 or more times to ensure repeatability. Then, the new setup (steel arms with les vertical cantilever and trutrack draglink) will be tested in the same manner and flex difference can be directly compared. If further sources of steering compliance exist after this, they will be identified and reduced as much as possible.

Regardless of the fact this test was not super scientific, I can tell you the steering system flex is significant. How I know this is, when driving down the highway, one can oscillate the steering wheel violently about 30° both left and right from center with hardly no effect to straight ahead motion. This tells me something, or many things, is/are flexing. You can watch the whole steering system move with the steering wheel with the car static on the ground up until the steering arm. The tie rod moves, but the wheel won't (up to a point obviously).

Maybe I can take a video to show you guys what I am seeing. It is very possible I'm missing something.

It just doesn't make sense to me- the size of that, & that the equivalent parts made by Stielow and DSS and others with access to modelling are if anything less beefy- that it would flex problematically. If it were a drag race part meant to guide pizza cutters over a few dozen miles of runs, adapted over to protouring, OK. But that is specifically made for Protouring.

I have been unable to find any comparable products from DSE or Stielow. If you have found some I would love to take a look at them and possibly procure them. The only steering arms I see on DSE's site for 67-69 camaro comes on their hydroformed subframe assembly. They appear to be made from steel forgings. Pics attached.