Something I forgot earlier. The last time we thrashed this to death, two other members came forward stating that they had also crunched the numbers. One had done it some time ago and another had done it very recently. That's three people doing it independently with no knowledge of the others.

All three came up with the same answer that confirmed the positive load on the yokes.

NO ONE has done the numbers and found otherwise.

I stopped my calcs at 1G, the other poster (who had done them himself recently) had continued to at least 1.3G at which point the yoke load did go negative.

It's a shame that entire thread was deleted. Still don't know why. Must have been the red faced table pounders.

 

and I will turn that back around... PLEASE show me and the rest of us your unquestionable cad cam data.... or something????


So, for a wrap... on one hand we have real world experience, and on the other we have???? what exactly???

 

Paul, where is this real world experience? All I see are unfounded claims and anecdotal evidence. It's just like Mike said. The people that did the math have one opinion. The people that have not have another opinion.

It really is that simple.

 

[B OK now we have established that yoke load will go positive at a certain point. I think we all agree that when that happens with a lot of endplay the results would be a drastic change in camber that would noticably affect handling and would be a safety issue. Now the thing that needs to be established is at what point and under what conditions this will happen. This is where we disagree. [/B]

Calculations and models use set parameters and variable parameters. On a level, smooth road you can get a specific result. Sway bar selection changes these parameters. Condition and type of bushings changes these parameters. Going uphill or downhill changes these parameters, hitting a dip or bump changes these parameters. The G forces encountered when cornering chages these parameters, Braking or acceleration during the curve change these parameters, Having a full or empty gas tank changes these parameters. Tire style, width, height, aspect and construction changes these parameters. Unsprung weight changes these parameters. Sprung weight changes these parameters. Having two people in the car changes these parameters. Front, rear bias changes these parameters. My question to you guys is, "Have any or all of these changing parameters been accounted for in your calculations"? If the answer is no and any or many of these variables have not been accounted for then how much does this alter the 1.3 G number and how accurate are the calculations? Crap in, crap out"

For two guys with engineering degrees I find it suprising you are both totally disregarding real world driving conditions, the multiple variations pointed out above and the differences in modifications and driving styles of the owners. This is the tech and performance section.
My impression of the thought process here is that "one of my degreed buddies did the math so this uneducated, clueless moron could not possibly add anything to this discussion" and "There is no way I could be wrong, I have a degree, Im never wrong." I am not trying to insult education here, not at all, just the arrogance that sometimes accompanies it.

Here is an example:
Your pushing your highly modified car hard taking a sharp curve at speed and hit a hump in the road, the suspension will load then unload. the #300 of inward pressure (questionable) changes drasticly at that point it might be a lot higher when hitting the hump then a lot lower after the hump.(changing parameters). The arc of the curve and weight of the car are contant at this point so the G forces encountered don't change, (fixed parameter at this point in the curve) your on the brakes a little because you just realised the little hump was there and this tranfers weight to the front and off the rear reducing the loading on the side yoke. (changing parameter) You have changed the variables in the model by a lot. The 1.3 G number is no longer valid. The camber goes positive at the exact time you don't want it to, the tires lose traction. Your dead or your car is totalled or both. Common sense. The calcs would have to be tailored to every possible variation. Nasa could do the math on this given enough time, you can't, too many variables.

If your cruising your factory stock corvette to the local NCRS meet with your prized OEM tires on it driving like Miss Daisy you might not notice or encounter these changes in camber. If you have poly bushings, aftermarket springs and performance 18" tires and wheels and doing your best impression of Danica Patrick you really don't want the upper control arm flopping back and forth and the camber change it will cause under any of these changing conditions.

I am done! Nothing I can say, no common sense, no facts, no pointing out numerous variables that quite likely were not accounted for in the calculations that no one has access to, no scenerio will change these two guys minds.

It is next to impossible to accuratly run the calculations as I pointed out above so I can't prove or disprove anything. Neither can you. Let's leave this alone. I think looking at the variables that have to have been left out of the calculations your initial pounding on the desk, red in the face position was correct. You were using common sense not a flawed model. Always go with your gut. If you have worn suspension components and you know you have worn suspension components there is nothing to be gained by not replacing them. period. Common sense.

 

One thing I'll add.
I just put mine together yesterday and looking at the yokes and clips: I can say that IF the forces on the yokes go negative... it can't ever be by too much force because that clip setup don't look all that strong to begin with.

-W

 

They ain't! And I've been saying that from the start! Just look at the damn things!

 

You claim to be an engineer. You should know better. If inward pressure is #300 and it takes 1.3 G's to go neutral then @ 2.6 G's the clip sees #300 of pressure pulling on it. I don't agree with these figures but they are the ones you swear by. This is evenly distributed pressure, tranfered to the side yoke and the clip only sees shear pressure. No pressure opening the clip. It would have to have enough pressure to shear the clip its entire circumference or rip the splines off the end of the halfshaft to fail. No one is claiming this would happen. I even doubt you would break this sliding sideways into a curb. This discussion is about how much force to go past neutral to affect camber. As I said you are the engineer, you should know better, if you don't it is a pretty sad statement as to the quality of our educational institutions.

You really need to read my previous post. You are defending a flawed calculation. Have you done the math? NO! Has Mike done the math? NO! Has anyone done the math factoring in the variable parameters I posted in post 104 2nd paragraph? NO!
GTR1999 posted his experience with worn yokes causing rear end handling issues. You ask where is the real world experience? Argue with him.

 

Do you all realize that this rear end has been out there almost 50 years now? What's really amazing, is that there is still room to argue about what it does and does not do.

But if all you tools can stop squabbling for just a moment
I still have a rear end question on the floor in a new thread.

-W (headed back down to the car works)

 

Guys,
I don't claim to have the expertise to resolve the difference in opinions on this. I've put a request in to an expert in C3 suspensions, who has no axe to grind at all, to see if he can settle this debate. I have no idea if he'll choose to take part in the discussion but I'm hoping he will. I'd like to see all members benefit from his vast experience and learn the simple truth, whatever it may be. If he's willing to get involved I'll post enough info to establish his credibility- trust me, he's credible. If he can't or won't take part I have another source in mind.

I bring this up now because I'd hate to see this thread locked up by mods before the discussion can be completed. I ask the mods to please keep this in mind and also ask you guys to keep things civil enough that mods won't be compelled to shut it down. Thanks & I'll let you know if/when I hear back from him.

 

Wrong on several levels. A sudden catastrophic failure would take a incredible amount of force, yes. But wear and damage can and do compound over time. If that cir-clip were repeatedly loaded under normal driving conditions, it would deform, fatique, and fail in relatively short order. My engineers eyes look at it, and they do not see a system designed to be used the way you think it is.

Wow ... STILL taking potshots at my education ehh? You really are butthurt by that aren't you? I don't give a flying rat's hind leg if you have GED or PhD. It really doesn't matter to me.

You're right. You haven't done the sums. I haven't done the sums. But even the limited amount of research I have personally done is more than you have.

 

First of all, I thought I was done... but it seems to live... so

My real world experience ... it happened to me, but I have said this like a gazillion times......and you say..."All I see are unfounded claims and anecdotal evidence" and WHAT have you given more than that yourself??? .... and..."It's just like Mike said. The people that did the math have one opinion. The people that have not have another opinion. ".... you keep saying this, and I keep asking, SHOW ME THE MATH!!! where do these "people" work at hanger 52? Roswell? PLEASE bring them forward?!?!? you cant keep saying we are right because the people told me so....need more.... I gave you much more

Please please please do... If I am wrong I would really like to know, thank you!

 

Quote:
Originally Posted by 63mako
You claim to be an engineer. You should know better. If inward pressure is #300 and it takes 1.3 G's to go neutral then @ 2.6 G's the clip sees #300 of pressure pulling on it. I don't agree with these figures but they are the ones you swear by. This is evenly distributed pressure, tranfered to the side yoke and the clip only sees shear pressure. No pressure opening the clip. It would have to have enough pressure to shear the clip its entire circumference or rip the splines off the end of the halfshaft to fail.

Wrong on several levels. A sudden catastrophic failure would take a incredible amount of force, yes. But wear and damage can and do compound over time. If that cir-clip were repeatedly loaded under normal driving conditions, it would deform, fatique, and fail in relatively short order. My engineers eyes look at it, and they do not see a system designed to be used the way you think it is.

Read my quote above. I said, using your figures it takes 1.3 G's to go neutral and 2.6G's to exert #300 of pressure on it. You could see 2.6G's in a fighter jet but never in a car. I never said the c clip was loaded enough to deform it under normal driving conditions. My point is that the 1.3 G figure is derived from a flawed calculation that is not taking all the variable parameters into consideration. If the actual tipping point was .7 G's then 1.4 G's would only put #300 of pressure evenly distributed on the clip. This is not enough to cause failure, fatigue or deformation of the c clip even if repeated. I have seen broken C clips though. I had a rear end with both C clips broken. Others have posted they had broken C clips. How do you explain this happening if the sideyoke never unloads? This in itself indicates the c clip does see substantial loading under certain driving conditions.





Quote:
As I said you are the engineer, you should know better, if you don't it is a pretty sad statement as to the quality of our educational institutions.

Wow ... STILL taking potshots at my education ehh? You really are butthurt by that aren't you? I don't give a flying rat's hind leg if you have GED or PhD. It really doesn't matter to me.

I stand by that statement. Look at your response above.





Quote:
You really need to read my previous post. You are defending a flawed calculation. Have you done the math? NO! Has Mike done the math? NO! Has anyone done the math factoring in the variable parameters I posted in post 104 2nd paragraph? NO!

You're right. You haven't done the sums. I haven't done the sums. But even the limited amount of research I have personally done is more than you have.

I really doubt that. You haven't even read post #104. The point, again is you haven't done the calculations, Mike hasn't done the calculations and no one has taken all the variable parameters into consideration when or if the math has been done. If every variable is not accounted for the results are not accurate. Crap in, Crap out. You, as an engineer should be the one that would realize this. Read Post # 104 instead of just posting back, Take the time to read it.

 

You know, I've been trying to keep it civil. Not once have I questioned your intelligence, education, or experience. But you want to keep taking jabs at mine.

Fine, the gloves are off.

You've made a whole slew of really freaking idiotic statements that show a fundamental misunderstanding of both very basic mechanics and physics. Things like not even understanding what Mike meant when he told you that the strut rod mount isn't positioned at the hub's centerline. Like taking the car's weight / 2 and applying it unilaterally to your elementary "formulas". Like assuming a linear relationship between the lateral and axial loading and etc. I'd say this is like debating with my 4 year old nephew, but that might be giving you too much credit.

Memory problems too, gramps? Senility setting in is it? Show me where I said it's never loaded. Pretty sure I said it was when the wheel is in the air. Of course they can break. They're fighting against that big azz spring back there after all (but not against the weight of the car). They can also pop right out of their groove if the stub axle wears down far enough.

 

That was just not right...
We all want to know the truth... I dont care as much as who is right and who is wrong... i just want to know.... there are two points of view, your and ours.... and you have shown nothing, and I am asking, please show us your numbers... do you have anything to show? anything? you never answered my questions, who are the "people" that made this test? when? what cad program?

thx,

 

He wants to keep making his silly little jabs at the degrees in the room for some reason. I tried to make it clear that it didn't matter one way or another to me. He's the one that brought up educations in the first place. I stood for it long enough. I'm done being nice.

And I've already answered this. I did not run a model. You have not either. What have you shown me? I proved to myself that the stub axles only get pulled outward when the rear suspension is unloaded. You can do the same test with your car. Why don't you? Knowing this, I tend to believe the people who claim that yoke endplay is not the horrible problem that everyone seems to believe.

 

ok nuff said

 

I'm not really sure how you intend that to be taken, but I was serious when I asked you to do the same test with your car. Why don't you want to? :

 

Perfect illustration of one of my main points in post 104.

Here is an example:
Your pushing your highly modified car hard taking a sharp curve at speed and hit a hump in the road, the suspension will load then unload. the #300 of inward pressure (questionable) changes drasticly at that point it might be a lot higher when hitting the hump then a lot lower after the hump.(changing parameters). The arc of the curve and weight of the car are contant at this point so the G forces encountered don't change, (fixed parameter at this point in the curve) your on the brakes a little because you just realised the little hump was there and this tranfers weight to the front and off the rear reducing the loading on the side yoke. (changing parameter) You have changed the variables in the model by a lot. The 1.3 G number is no longer valid. The camber goes positive at the exact time you don't want it to, the tires lose traction. Your dead or your car is totalled or both. Common sense. The calcs would have to be tailored to every possible variation. Nasa could do the math on this given enough time, you can't, too many variables.


I know, that sounds like something your 4 year old nephew would say.

 

I do, because I want to learn, and I want to know the truth...
but i want to be civil about it..

I have had my wheels off more times than I want to think...

yes, with the wheel off, neg pressure, with wheel down pos pressure, I understand this... but how do you simulate 3500 lbs of lateral pressure?

 

Nice. I am a grandfather. Do you have one? Is that how you talk to him too?