mounting shocks

[Bugpac]

[quote=yoshi\";p=\"72235]

Originally Posted by "Bugpac\";p=\"72230":3j8tg49f

No I feel a pm to me, Im on a short rope.... *Im not trying to start a piss fest with you yoshi, just trying to keep you consistent....

oh, lol. *I didn't think anything you said was outta line, and I see how you may have thought I was belittling you saying your were an enthusiast, which is why I explained myself after...[/quote:3j8tg49f]

I was just looking at were the road was going, not were we were parked at on the side....

[masterfabr]

Originally Posted by yoshi\";p=\&quot

hey master, I misspelled flammatory a few post up, can you fix it for me, lol......

actually, I think I misspelled it again, spell check won't bring up the correct spelling, just says inflammatory, is that right, or is flammatory(sp?) correct?...lol

* Yes yoshi you are INFLAMMATORY .

[yoshi]

[quote=masterfabr\";p=\"72237]

Originally Posted by "yoshi\";p=\"72232":2h2fz4nl

hey master, I misspelled flammatory a few post up, can you fix it for me, lol......

actually, I think I misspelled it again, spell check won't bring up the correct spelling, just says inflammatory, is that right, or is flammatory(sp?) correct?...lol

* Yes yoshi you are INFLAMMATORY . [/quote:2h2fz4nl]cool,..so go edit my post to say "inflammatory" please,...lol

[K-fab]

The lever is the a-arm.
The effort comes from the tire
The mounting point of the a-arm on the chassis is the fulcrum
The shock is what balances the load input and controls everything.



What we're concerned with (and debating) is the two ends of the lever, one stationary (fulcrum) and one movable (effort)
And
The two ends of the shock.
And
The relationship of these four points to each other at a specific point of motion - the full bump, in this case.

So let's start out with our a-arm:
It does not matter how you connect the two points, just as long as they are attached to each other in some fashion.
(see first pic below. *All are structures that will allow one point to rotate about the other if one point is secured.)

You can have a crescent shaped structure between the fulcrum and effort.
Or you can have a straight line.
Or a curvy line.
Or a swoopy S shaped unit.
Or multiple z-bends.

As long as there are two end points (fulcrum & effort) there is ONE line that concerns this - the straight line BETWEEN THE TWO POINTS (show in blue in the first pic below); each end of a structure, if you will. *This line may be obvious (straight piece of tubing) or 'imaginary' as far as the eye can see. *In physics, it is there.

They taught us to get rid of all the crap around/between/above/below these to points and to treat it as a straight (blue) line when dealing with loads on a lever.

This is the line that represents the radius of the curve that the a-arm follows as it moves. *This is the line that the system works around.

Now throw in the shock. *The shock represents the vector of movement.


The vector is the motion of the shock as it gets compressed. *It is being pushed by the lever at the load point.

If you go back to the drawing where I put the green (shock vector) line between the two mounting points of the shock and the yellow line (blue in the pix below), you'll see that these two lines are perpendicular. *It does not matter where the shock is mounted as long as these two lines are perpendicular to each other at full bump.

While you want to take the red lines as the input to the shock by the system, it is incorrect to do so. *It is all about the forces in the system and the relationship between these two forces.

Master - I've been searching all over the internet to find an example, but all I can find is a few elementary pics that you see, along with my Yoshicad work.
I'm not trying to argue with anyone - I'm trying to show you the science - physics - behind the idea. *Physics was my favorite group of engineering classes - I did extremely well in these classes, other than the dreaded Lens stuff - that was screwy.

[masterfabr]

At this point all I see is a standoff.There is room IMO to say the experts are seeing the pic wrong and the same can very well be said in reverse also.Even the experts are not in agreement nor are the "lowly ignorant enthusiasts" . *Need more input/reference material.you know-"not enough data to compute".LOL!!!!

[K-fab]

I understand your stance and point of view. *You would not pass the test in class, though. *

I would. (I have!)

I can't figure out how to show you the physics behind the correct answer though and it's driving me nuts! *[smilie=banghead.gif]
No, wait... that would be the steering wheel in my pants * * [smilie=icon_bolt.gif]

Thus far, I must say that this debate has stayed quite civil and pretty much in line with what a good debate should be. *I thank you all! *Keep it up.

I'll go dig around in my Machinist Handbook - there are some in depth discussions on these sort of things in them.

[masterfabr]

Originally Posted by K-fab\";p=\&quot

The lever is the a-arm.
The effort comes from the tire
The mounting point of the a-arm on the chassis is the fulcrum
The shock is what balances the load input and controls everything.



What we're concerned with (and debating) is the two ends of the lever, one stationary (fulcrum) and one movable (effort)
And
The two ends of the shock.
And
The relationship of these four points to each other at a specific point of motion - the full bump, in this case.

So let's start out with our a-arm:
It does not matter how you connect the two points, just as long as they are attached to each other in some fashion.
(see first pic below. *All are structures that will allow one point to rotate about the other if one point is secured.)

You can have a crescent shaped structure between the fulcrum and effort.
Or you can have a straight line.
Or a curvy line.
Or a swoopy S shaped unit.
Or multiple z-bends.

As long as there are two end points (fulcrum & effort) there is ONE line that concerns this - the straight line BETWEEN THE TWO POINTS (show in blue in the first pic below); each end of a structure, if you will. *This line may be obvious (straight piece of tubing) or 'imaginary' as far as the eye can see. *In physics, it is there.

They taught us to get rid of all the crap around/between/above/below these to points and to treat it as a straight (blue) line when dealing with loads on a lever.

This is the line that represents the radius of the curve that the a-arm follows as it moves. *This is the line that the system works around.

Now throw in the shock. *The shock represents the vector of movement.


The vector is the motion of the shock as it gets compressed. *It is being pushed by the lever at the load point.

If you go back to the drawing where I put the green (shock vector) line between the two mounting points of the shock and the yellow line (blue in the pix below), you'll see that these two lines are perpendicular. *It does not matter where the shock is mounted as long as these two lines are perpendicular to each other at full bump.

While you want to take the red lines as the input to the shock by the system, it is incorrect to do so. *It is all about the forces in the system and the relationship between these two forces.

Master - I've been searching all over the internet to find an example, but all I can find is a few elementary pics that you see, along with my Yoshicad work.
I'm not trying to argue with anyone - I'm trying to show you the science - physics - behind the idea. *Physics was my favorite group of engineering classes - I did extremely well in these classes, other than the dreaded Lens stuff - that was screwy.

k-fab I made the post above before I saw this.I actually agree with you now.Good work and I appreciate it but it also brings another question/doubt into my mind.I asked earlier but can you explain why the actual lower imaginary lever and possibly correct lever would not be the line from lower inner a arm mount and the C/L of the spindle where it meets the line from top outer heim and lower outer heim ?

[K-fab]

Originally Posted by masterfabr\";p=\&quot

can you explain why the actual lower imaginary lever and possibly correct lever would not be the line from lower inner a arm mount and the C/L of the spindle where it meets the line from top outer heim and lower outer heim ?

Can you rephrase this a bit? *I'm lost and don't quite understand.

Are you asking about the "red lines" and the angle between them and the yellow?

The lower a-arm is a structure and the location of the mount on this structure (at least in the sense of motion) doesn't really care where it's mounted. *Even though the force of the lower shock mount is technically below the yellow line, the system sees it as one point along the yellow line.

but now you throw in spindle C/L - as in kingpin and where it mounts to the end of the a-arm?

Man, my brain hurts! *

[masterfabr]

Just draw a line from the lower inner pivot to the C/L of the spindle where it welds to the upright. Mount the lower shock eye to this imaginary line.Would that not be the true effective lever line?

[K-fab]

Originally Posted by masterfabr\";p=\&quot

Just draw a line from the lower inner pivot to the C/L of the spindle where it welds to the upright. Mount the lower shock eye to this imaginary line.Would that not be the true effective lever line?

I see where you're going now.

Man... I know the answer, but how to explain it? *My brain has gone on hiatus! *

The answer would be No. *It has to do with the suspension system being more than one lever (lower a-arm). *You're now throwing in an upright (spindle) and you need to have a control arm (upper a-arm) to keep everything from rotating in. *

It becomes a structure problem instead of a simple lever situation.

In the grand scheme of things it all goes back to that one lower a-arm that supports the entire system, at the load point (spindle) and fulcrum point (chassis mount).

ouch, ouch, ouch. *Brain cramp!

I'm gonna bail for the evening on this one. *[smilie=blowkiss.gif]