[MB968]

Don't have to worry about me going off in a huff; not who I am. But, in the case of this thread, I just know when I'm trying to discuss something in the science realm with someone who really doesn't understand the science down at the micro level. At some point, it just isn't worth discussing any more.



And, don't worry, you'll definitely see me chiming in again when I feel my knowledge is petinent, and especially when I know the science is being misrepresented. I'll stay out of the fray when it isn't in my knowledge base, other than usually to ask questions for my own understanding, or as in the case of the recent cam tooth breakage to offer a variety of ways that I could see the failure having occurred. Hopefully giving food for thought for further dialog. And, I don't mind being corrected, and there are definitely times when it is appropriate. So, have at it, you'll never offend me no matter what. As in class 8.8 which I incorrectly stated as grade 8.8. I spent 40 years discussing/agruing with engineers whose problems I was charged to fix. And, in the process as long as both parties were open minded, we both learned from one another. It is a process I enjoy, and hope to be involved in here. I continue to learn more of the science of engineering every year.

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[flash]

there are layers here that you may not have considered.



don't make any assumptions about what i do or do not understand. i choose carefully just how detailed i get on this site, and frequently have to put things in terms the larger audience can understand. this is NOT a discussion between 2 people. we are speaking to a group, all with very different backgrounds and levels of understanding. it is easy to make the mistake and assume you are talking to just one person. everyone should write as if you are talking to everyone, not one person.



for liability reasons, i also am very careful about any recommendations i make. i think everyone can understand that.



i also spent a lot of time arguing with engineers who were stuck on stupid, couldn't see the forest for the trees, and didn't understand the real world applications of the things they were working on, which frequently went against everything they knew.



by the way, engineering is not a science. it is an application.



again, ironically we both agree on what to use. isn't that really the point?

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[tamathumper]

If I might interject, I learned several things that I would not have known to consider just because you guys were having a discourse. So thanks for that.



Specifically, I'm still curious about the bolt and whether or not it is subjected to cyclic loads (I assume meaning "passing zero" between tension and compression) or only subjected to varying tensions (from fastener torque at all times, and also even more when the strut "pulls away"). Inside my head where everything works just fine before it gets out, I can see how it might only be subjected to varying amounts of tension?



I am not an engineer, I do not play one on TV, and now perhaps I've also learned not to interject.

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[flash]

tough question to answer.



the springs are cyclic. there is a specific frequency. the struts react to that. the hardware resists it all in varying amounts, dependent on the force applied to the strut.



lol - so the answer to your question is yes.

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[94SilverCab]

MB968...please, please...don't go away. Flash needs to be told occasionally/frequently that he is a butthead (scientifically speaking of course)...oh, and (almost) never gives up, so have at it.



Jay

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[flash]

lol - all this fuss and all stemming from me misreading something. it's hilarious that we both fought so hard to support the same side of the same point, from different sides, and neither paid attention to the fact that both were right. anyway, enough about that.

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[MB968]

[quote name='tamathumper' timestamp='1360753789' post='138704']



Specifically, I'm still curious about the bolt and whether or not it is subjected to cyclic loads (I assume meaning "passing zero" between tension and compression) or only subjected to varying tensions

[/quote]



Answer it no to cyclic, and yes to varying tensions. This is bolted joints 101. As I keep on saying, this isn't that difficult to understand. Most people with any techincal savy can understand it if just presented in the right way. All my dialog above was never about the bottom line of which bolt to use, in all likelyhood, any reasonable quality bolt would work. My dialog about the misconceptions being given as to how things work. This one is pretty simple. Think of it this way. If the bolt goes through a state of zero load when it passes from tension to compression, that in turn means the joint also goes through a state of no load (you know the old equal and opposite thing). Thats when things start coming apart.

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[flash]

by definition it is cyclic. the hardware goes through a push-pull motion every time the spring moves. the spring moves a minimum of 2 directions every time it moves at all. this is a spring cycle.



at the risk of sounding as pedantic and condescending as many of the posts above (mine included), this one is pretty basic, and anybody with any understanding of suspensions should get it



and the point of the thread is ALL about what hardware to use. anything else is irrelevant drivel (including my diatribe)

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[Cloud9...68]

Funny - so after all that, it comes down basically to, "any good quality bolt (actually nut) should do." To tell you the truth, I'm a lot more concerned about the flimsy piece of sheet metal that constitutes the strut tower that supports the strut, my 700 lb/in springs, and the insanely high cornering and braking forces that my car is going to generate, especially with the 18" wheels, and uber-heavy duty Racers Edge geometry correcting A-Arms (with the thick ball joint pins). But I'm grateful that I have the D1R strut tower brace, as the brackets look like they'll add a lot of reinforcement to the towers.



As a side note, bending of the strut towers is a common problem on BMW E46's. It happened to my daughter's 04 on the drivers side, and unfortunately I wasn't aware of it until I noticed the tires were wearing very fast along their inner edges. Ruined a nice set of expensive Michelin all-season high performance tires. I straightened the tower, got it aligned, and installed a reinforcement plate between the top strut mount and the tower on both sides.



Sorry to get off the subject of the hardware, but I think this has been sufficiently beaten to death, anyway.

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[flash]

lol - i am just as concerned. i've seen a few of them cracked due to braces or springs that were too stiff. frankly it wouldn't be the worst thing in the world to weld in more material, but you'd have to go all the way out to the edge.

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