shock angle??.

[Hacked850]

I read somewhere that the angle of the shock affects it's stiffness?/,is this true?.If so does the shock get stiffer the more vertical it is mounted or is it the other way around??.

 

[Guest]

Shock Angle

Shock Angle

I read somewhere that the angle of the shock affects it's stiffness?/,is this true?.If so does the shock get stiffer the more vertical it is mounted or is it the other way around??.

Normally,the more you angle the shock over,the stiffer (higher spring rate) the spring will need to be.I have a chart that shows how much stronger a spring you would need for different angles.Of course this is for a coil over shock absorber.A plain shock isn't affected by angle of mounting.Probably would'nt work well upside down,horizontal is okay.

 

[Steve]

It's not so much how "vertical" it is, what matters is how it relates to the direction of travel compared to the pivot point.

It's all about 'mechanical advantage', and it has the most direct ratio when the shock is perpendicular to the direction of travel.

.

 

[RichDesmond]

It's not so much how "vertical" it is, what matters is how it relates to the direction of travel compared to the pivot point.

It's all about 'mechanical advantage', and it has the most direct ratio when the shock is perpendicular to the direction of travel.

.

Exactly. The "zero point", at which the shock will feel the stiffest, is when the shock's two attachment points are equidistant from the swingarm pivot.

 

[Mad Mark]

if the shocks are mounted lets say right over the rear axle the shocks will stiff. if you move them closer to the pivit point of the swingarm they will be softer because they have more leverage on them. pretty much what Steve said. and also if they are angled more you get more travel, so you have to take that into account too.

 

[Hacked850]

Ok here is the reason I asked this question.
I have a 1982 GS850G sidecar rig,it's heavy ( about 750+lbs ) and I have gone thru several rear shocks trying to find some that will work with the weight.I finally got some NEW Harley air shocks off one of there big full dressed touring bikes,I know the Harley weighs about what my rig weighs.Even at 40psi the shocks are barely enough.So what I was thinking was to relocate the shock mounts to a more vertical position for a stiffer setup.
So lets say that I mount pretty much straight up and down close to the rear axle,in theory they should be stiffer??.

 

[RichDesmond]

Ok here is the reason I asked this question.
I have a 1982 GS850G sidecar rig,it's heavy ( about 750+lbs ) and I have gone thru several rear shocks trying to find some that will work with the weight.I finally got some NEW Harley air shocks off one of there big full dressed touring bikes,I know the Harley weighs about what my rig weighs.Even at 40psi the shocks are barely enough.So what I was thinking was to relocate the shock mounts to a more vertical position for a stiffer setup.
So lets say that I mount pretty much straight up and down close to the rear axle,in theory they should be stiffer??.

As has been said, more rearward mounting and getting the shock mounts equidistant from the swingarm pivot will make the effective spring rate higher.
As a practical matter, that won't be vertical, it will be inclined forward somewhat.

 

[Steve]

So lets say that I mount pretty much straight up and down close to the rear axle,in theory they should be stiffer??.

No, as I mentioned earlier, and as Rich Desmond confirmed, it's not the "straight up and down" that matters, it's when the two shock mounts are the same distance from the swingarm pivot.

Measure from the swingarm pivot to the lower shock mount.
Now measure from the swingarm pivot to the upper shock mount.
You will see that they are rather close to the same measurement.

I don't have a bike handy to take actual measurements, but looking at a picture in the service manual and comparing the two distances, it appears that there might be a difference of about two inches. You would either need to move the upper mount to the rear two inches or the lower mount forward two inches.

There are two problems with moving the lower mount forward: 1. there is noplace to move the mount to. 2. that would change the leverage ratio, making the springs appear softer than they already are.

Moving the upper mounts rearward would also require some custom fabrication, as their current location is wonderfully braced for the load of the suspension.

Now, let's go back to the beginning and get some clarification. :-k
Apparently, you are not satisfied with the "stiffness" of the shocks. Are you unhappy with the spring rate or the damping qualities? They are drastically different.

Not sure if RichDesmond can help you with shocks, but he is rather directly connected to Sonic Springs, and might be able to help your situation with some experienced recommendations.

.

 

[dr_fosg8]

Have you tried these guys?

http://www.davequinnmotorcycles.com/cgi-bin/webc.cgi/HAGON_TWIN_SHOCKS.html

Several members here have been happy with them in the past. They will build you a custom shock based on the weight of the setup. They may have something that will work for you.

 

[john82q]

There are two problems with moving the lower mount forward: 1. there is noplace to move the mount to. 2. that would change the leverage ratio, making the springs appear softer than they already are.

3. your swing arm is not strong enough, closer the mount is to the middle the greater the bending force will be.


Maybe you need to redistribte some weight forward, instead,
or change the sidecar wheel lead.