I am an engineer, and theres big bending force there

 

lmao.

we're gonna try once more to soak and pry off those abs connctor sensors. they worked fine before this, would like to keep them. if it proves impossible, i think i will just go ahead and get the pricey "good" abs sensors from rock auto. we made a lot of changes to the car in one sitting, so i want to make sure it all goes properly.

 

ok. should the inner/cam bolts be larger and of harder material then?

 

The spring pushes on that arm, that's considered a bending force. Every time you hit curbing or a pothole, there is a bending load being transferred through that arm. The arm does experience tensile and compressive loads but typically shear and bending conditions are much more harsh on parts.

I really need to get some projects off my plate so I can finish the arm design I started...

 

from when you have to salvage your car from the bottom of the ocean.

 

yeah but the weight is toward the tire contact patch. the control arm is just a swing arm (that could be stretched or compressed)
may be theres a "lever calculator" online somewhere

 

This is easy math for any engineer I would hire to calculate the max moment at the thread base and compare to strength and fatigue life based on lookup data.

But in the end, threads in bending dont belong on track.

 

So you're thinking the threads wont hold if being pulled?
if the wheel/tire is pushing 1000lbs upward, the shock mount is the fulcrum, 1:6 distance from the fulcrum, then the ball joint will "work" 167 lbs.
I dont think you can bend a 6" stainless steel threaded rod, even with 500 lbs. thats what i'm thinking. you can pull 3000lbs with quick links, which probably just 1/2" diameter

 

The shock is trying to turn the whole arm into a U. I get where Dallas is coming from, but I'd like to see the math on it. The size rod/rod end used is pretty strong.

 

This made me LOL










When I raced off road that is a big no-no to run any rod in in a side load like that. I wouldn't put that on my car if you gave it to me.

 

has anyone ever done a pole in the motorsports section of how many engineers are on here? i suspect it would be a larger % than the standard population.

when i was racing DH mountain bikes we got stuck at the start hill in UT at a national race. all of the guys got to talking and it was something like 20 out of 32 guys were either mechanical engineers or going to school to be an ME.

 

If you don't have at least a basic understanding of statics you're not going to guess the right answer. And there is a lot more than 1000lbs pushing up on the tire at times.

Based on some measurements I have and a rough guess on where the threads start on that body, there's around 290,000 Nmm of moment at the thread in a hard bump. Hard to see what that thread size is, but if I assume its an M16x1 my example would have 885mpa of stress at the root not account for stress concentration. That's effectively failure load.

 

if you have a solid tire and the shock is mounted at the middle of the arms, sure. might you the sprung weight is only 225 lbs. quadrulple that and you still cant bend that threaded rod.
i think my 20 TON shop press can do it.

 

Double check my work... I could have gotten something wrong.

Force is based on the fact I know I can close the 2" gap from tire to fender on a hard hit. So Im compressing a 1450 lb/in spring by 2*0.76 inches. Dimensions of the arm are from one of my cad models, distance to thread/body intersection guessed at 125mm.

 

Funny: I started out as an engineering student. I think all of here are like minded in that way, which is why we are still here.