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Someone good with physics?

  • Thread starter Thread starter makenzie71
  • Start date Start date
M

makenzie71

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Okay, I'm wanting to move my lower shock mounts closer to the pivot bolt. Will this increase or decrease the load on my shocks?

The way I understand things, having the shocks at an angle (as opposed to perpiindicular to the swingarm) increases the load. Also, the wheel axle being located outside outside the lower mount increases the load on the shock.

Moving the lower shock mount two inches in would give the axle two more inches of leverage on the shock. However, moving the shock closer to perpindicular to the swingarm should decrease the leverage on the shock.

Is that right or am I misinterpreting things?
 
Moving your shock mounting point towards the swingarm pivot point will make the shocks feel softer (more leverage on the shock). Making the shocks more upright will in effect act to stiffen the shocks feel. Overall, the shocks would feel softer.
 
Well I read a bunch of newt's laws and did some math...and then had someone who knew what they were doing go and do it right...and moving things around the way I have in mind would end up with me having less stress on the shock...but not that much. I looked at moving the upper mount back, but that'll reduce travel too much. It's all fun.
 
You can avoid the trigonometry for the present and think of the swingarm as a giant nutcracker. Moving the lower shock mount toward the pivot will act as increasing the force and reducing the travel.

I doubt you'll get the results you need if the shocks are far away from your desired handling by just moving the mounting points.
 
Nothing can cure their handling attributes...it's their length that's an issue. I would like to avoid building a "high" lower mount to keep the same geometry. My problem is the shocks are about 1.5" too short for my needs, and require an adapter to mate the lower. Mating all new stuff up lets me move the lower mount anywhere I want, and I can ditch the clevis lower mount and run eye/eye shocks.
 
makenzie71 said:
Nothing can cure their handling attributes...it's their length that's an issue. I would like to avoid building a "high" lower mount to keep the same geometry. My problem is the shocks are about 1.5" too short for my needs, and require an adapter to mate the lower. Mating all new stuff up lets me move the lower mount anywhere I want, and I can ditch the clevis lower mount and run eye/eye shocks.
Click to expand...
Well, then moving the mount towards the pivot will make up a bit for the length, but if the springs are soft (as I think you've stated earlier) it will just make them worse.

Are replacement springs available? I gotta' say you have more patience than I. Ever hear of the phrase 'polishing a t u r d '?
 
Here's a bit more for you to chew on - physics related.

The total energy the shock is required to absorb is the same no matter what mounting points you use. In this case (static loads, not dynamic) the energy is derived from the force times displacement. So, if you move the shock mount towards the pivot, you reduce the displacement and must increase the force of the spring to compensate. Likewise if you increase the shock angle, you reduce the displacement and the force must also be increased.

More detail can be had by using trig relationships, but you get the idea.
 
I thought the further the shock was from perpendicular to the swingarm, the less effective it was?
 
makenzie71 said:
I thought the further the shock was from perpendicular to the swingarm, the less effective it was?
Click to expand...
The less travel it has. Effectiveness of the shock is based on what it was designed for. The maximum travel would be tangental to the arc of the swingarm, not perpendicular.
 
Okay I said that wrong...not talking about travel (though I'm trying to keep that as open as I can). Perpendicular to the swingarm would be the least possible amount of travel, but wouldn't it require more force to compress the shock at that 90* than the 45* angle it's currently at?
 
makenzie71 said:
Okay I said that wrong...not talking about travel (though I'm trying to keep that as open as I can). Perpendicular to the swingarm would be the least possible amount of travel, but wouldn't it require more force to compress the shock at that 90* than the 45* angle it's currently at?
Click to expand...
Yes it would. When I say the force must be increased to maintain the same capability to absorb energy when you move the shock off of the tangental, I mean the spring force. I guess the confusion arises when we talk about increasing the shock angle. What reference we use for this angle can confuse the issue.
 
I have a hard talking angles when it comes to stuff like this because it always seems like I'm talking about the angle from the opposite side the other is talking about and increasing/decreasing mean the opposite to each of us lol.

Either way, final solution is unavoidable...heavier springs. Even when I throw in the new swingarm I'll have to keep the same geometry, or put the shock even further from perpendicular to the swingarm because of travel.

It's something I didn't mention before...somewhat of a brain fart...but the new shocks only have 1.8" of travel before hitting the bump stop, where as the GS was designed for a shock that has 2.15" of travel. I've considered taking the bump stop out of the new shocks, but I really don't know how damaging it could be to actually bottom the shock out on the road.
 
makenzie71 said:
Either way, final solution is unavoidable...heavier springs.
Click to expand...
You're probably right. When you get that sorted out, then you can address damping.

You definetly have more patience than me. :clap:
 
It's less about finding known good shocks and more about proving these shocks are acceptable/garbage.:)
 
I see. Inquiring minds? :D

I have a biased, and very negative, opinion of most Chinese products. Not that they can't make it right, there's just little incentive since Americans buy most anything if the price is right.

Good luck to you.
 
perpendicular or at 90 degrees is the easiest- least resistance == need more spring rate on a shock to suspend a given weight.


every degree away from perp. means less spring rate required to suspend the exact same weight. more stress on the shock mounts-yes . by leaning the shocks away from 90 degrees you are making a mechanical compression dampener.

steep angle will assist a light spring to become "stiffer"

easiest way to explain.
 
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