mounting shocks

[LiveWire]

[quote=yoshi\";p=\"72016][quote="bdkw1\";p=\"72014":36a1wd6j]

Originally Posted by "yoshi\";p=\"72003":36a1wd6j

Your sock angle is correct, your trying to get 90 degrees to the inner and outer mount, you don't factor in the lower shock location as part of the 90 degree angle..

Yes, you do. Since your a bike guy, go look at a Buell and tell me how the shocks on those work since they lay almost parallel to the swing arm pivot and axle.[/quote:36a1wd6j]It's a cantilever setup, *which allows you to put the shock in any position you wish, your not comparing apples to apples....

Here is a drawing to illustrate what is happening. *Pretend your pushing this triangle straight up, the outer red dots represent the a-arm mounts, the blue represents the shock angle. *The bottom pic would represent a shock mounted under the a-arm, the top represents above. *I know it is prob. a little extreme to what usually goes on, but having an extreme angle shows you clearly what is happening. *If you were to push this triangle straight up (which represents full compression) the shock in the middle (90 degrees to the mounts) will be more progressive, where lining it up 90 degrees off the inner mount and the shock mount (like you are saying) throws it way in or way out depending on where you mount the shock. *The shape of the a-arm, and the lower mount for the shock, don't matter, all that matters is that the load is transfered to from the a-arm to the upper shock mount in the most progressive way possible...........

In a cantilever setup, the shock is always seeing the most progressive load since the shock ends up being 90 degrees to the cantilever arm at full compression...[/quote:36a1wd6j]

bdkw1 is right. I'll let him beat himself senseless against a wall trying to make you understand why. *[smilie=banghead.gif]

The top picture if used with the vertical shock would have a digressive motion ratio past a certain point in the travel.

[masterfabr]

Don't argue with yoshi! *

[jerry]

Please do not take offence, *i going with *Yoshi *only because i understand him..

[yoshi]

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

Don't argue with yoshi! *

lol,..if someone can make a good argument to why I am wrong about anything, i'm all for it, I would rather be correct with my info then think i'm right when i'm wrong. *What I said is what i've always been told, and it makes complete sense to me....

[K-fab]

[quote=bdkw1\";p=\"72014]

Originally Posted by "yoshi\";p=\"72003":2tnq8mix

Your sock angle is correct, your trying to get 90 degrees to the inner and outer mount, you don't factor in the lower shock location as part of the 90 degree angle..

Yes, you do. Since your a bike guy, go look at a Buell and tell me how the shocks on those work since they lay almost parallel to the swing arm pivot and axle.[/quote:2tnq8mix]If memory serves, the Buell uses a pull type setup on the shock. *The shock is mounted on a lever arm that comes off of the bottom of the swing arm and as the suspension compresses, it actually pulls the shock apart for compression and pushes the shock together during rebound.

Regardless of push/pull, it still works off of an arm that comes off the swingarm and takes the rotational movement of the swingarm and changes it's direction roughly 90 degrees so the shock can parallel the swingarm.

At least this is the way the Buell I saw years ago (mid 80's) at Daytona was set up. *Mind you this was a one off purpose build BOTT (Battle of the Twins) race machine and it was mostly a hand made "Factory" machine of it's era.

I can't recall exactly how they captured and pulled on the spring from the "chassis" end of the shock - seems like it was in some sort of collar that had a pair of rods that attached it to the swingarm mounting end of the shock. *I remember it being quite complicated looking.

Taking a look at Buell's web site doesn't show squat. *At least that I can find. (and I'm not in the mood to search around some dumb flash loaded site that you have to wait for so it can do it's stupid bling bling crap. *Give me a web site that goes to the info quickly and shows things in a straight forward manner! *[smilie=banghead.gif] )

[masterfabr]

[quote=yoshi\";p=\"72046]

Originally Posted by "masterfabr\";p=\"72044":38ljwkhi

Don't argue with yoshi! *

lol,..if someone can make a good argument to why I am wrong about anything, i'm all for it, I would rather be correct with my info then think i'm right when i'm wrong. *What I said is what i've always been told, and it makes complete sense to me....[/quote:38ljwkhi] LOL!!!!! Just kidding! We all know you and I both like a good "discussion".

[bdkw1]

Pretty good memory K-fab. The end of the shock body had a collar holding the spring. It was then compressed from the top with 2 pieces of all thread. I guess the new Buells are different, I had to go look at them. They now look sort of like a early 80's YZ before they had linkage.

Anyhooo, it's Yoshi cad time. (image not to scale, for reference only )



OK, both suspensions are bottomed, both are running the same length of shock and the distance from the arm pivot to the shock mounts are the same. They will have the same motion ratio and leverage as each other even though the top one has the shock parallel to the arm. The a-arm in this picture is the same just less exaggerated.



Any amount that the shock pivot is above the center line of the pivot axis of The arm and the wheel needs to compensated for. If that arm is 1" tubing and the tabs put it another .625 up, then you are 1.125 above your pivot axis and your shock angle must change accordingly. Pretty simple geometry.

[jerry]

Ok i see your point, but if travel is the same and the ratio is the same then what is the differance other then the math. *How does it effect the ride or what is being effected.

[bdkw1]

Having the shock at 90 deg to the pivot axis at full bump will yield the most force/damping out of it. When you go past 90, your progressiveness really starts to take a dive making your car easier to bottom. If you lean them in too far on the other hand, they get more progressive but can become a pain to tune. Your spring rates and damping requirements also go up. This can overwhelm a smaller shock.

[yoshi]

This is crappy photoshop stuff, but you can do it in CAD if it is easier for you to follow, as I am hoping the way I drew this is understandable for people, lol..

Basically, to have a progressive rate, you want the lower shock angle to swing in an arch that is as far off from the arch of the upper shock mount. *In other words, the closer the 2 circles line up, the less progressive the shock dampening is.

Below are 2 drawings, the first one has a shock mounted in line with the inner and outer a-arm mounts. *The blue represents the arms, the yellow represents the shock in full compression, the turquoise. represents the shock at full extension. Everyone will agree that the upper shock location will be the most progressive location for the shock at full compression in this drawings.

The red circle represents the shock arch to the left (the incorrect upper mount)
The green circle represents the 90 degree angle (the correct mount)
The black circle represents the inner mount arch, which is what causes the lower shock mount to swing on a different arch than the upper mounts.

Looking at the first picture, (which everyone will agree the upper mount, green circle, is correct) it's obvious that the lower mount travels almost directly against the green circle, where the left mount shock, actually travels more to the right of the red circle, meaning it's not as progressive as it follows a little more of the red circles arch...


Now, the second drawing is the same thing, only it has the lower shock mount at the top of a triangle. *Using the same colors and info for the first drawing, you can see that the upper mount to the left follows more of the red circle, where the upper shock mount at the top of the page following the green circle doesn't, meaning it's more progressive.....