Ok, here's what I did. These results are not linear because the springs on the rear suspension are progressive. The results are telling nonetheless.

1. With the suspension stock I took an angle measurement with an angle finder. I put the angle finder on top of each piece that goes over the square torsion bar. In the 2005 Sportsman 500 parts manual Polaris calls it the "Arm, Stabilizer Bar" part # 1580107-067.

2. Then I put 180# on the rear rack as far to the right as possible. Basically I had someone stand there.

3. Then I measured how much the angle changed on each side.

4. On the right side the change was 12 degrees. On the left side the change was 3.5 degrees. What this tells us is that the torsion bar is absorbing quite a bit of the energy and only sending a small amount to the other side.

5. Then I disconnected the torsion bar on the left side using the "sway bar disconnect kit" so that the left and right side are not connected at all.

6. Then with the same 180 # in the exact same place on the right side I measured how many degrees the suspension changed. The change was 16.5 degrees. So by disconnecting the left side so that each side can act independently there was an additional 33% compression on the right side. Remember this is for a specific amount of force. As a result of the rear springs being progressive these results will not be linear.

Have fun with these results.

 

Jeff,
What are you trying to say? With the sway bar disconnected, the compression will obviously be more. The true test or measurement to me would be how much force it takes to get the suspension to compress from full extension until a certain point, with both the sway bar connected and then disconnected. That way you could measure the effectiveness of disconnecting the sway bar and riding uneven terrain.

I think that you would see that my observations of the disconnect would be pretty close. That at anything faster than a crawl, the suspension dives too much when the sway bar is disconnected. This is only when hitting something that one tire would drop in to and not the other.

Did you try putting the weight on the other side and make sure spring tension is about the same, same angle change?

good observations, not sure what they tell....but at least your getting in the garage and doing some testing....

dave

 

Dave,
I only had one question for today's test. I wanted to make some assessment of what percentage of a given amount of energy applied to the suspension on one side would end up on the other side after it went through the torson bar. That's all for part #1 of my data gathering. More to come.

 

Thanks Jeff....looking forward to the rest of the testing....

 

Anyone else?

 

Jeff, i think this is what you are looking for ...


http://www.offroaders.com/info/tech-corner/rti.htm

This is the RTI score used in jeep off road.

IMO this is what we should be using for testing, as it's the off road standard.

[img]i/expressions/face-icon-small-smile.gif[/img]

 

Hey jefffoxsr. I think thats a great way to get an understanding of what the sway bar does. Another thing you might try would be to put a torque wrench on the torsion bar on the end that is disconnected. This would allow you to measure the spring rate of the torsion bar.
BryceGTX

 

Chris,
Awesome link. As you know I did some of the ramp testing last year with my outlander vs. my friend's 2004.5 sp500. I did the outlander with and without the sway bar. A person named Andy Bassham, who is on this forum, also did some testing with his2002 grizzly and a friend's arctic cat 500. Andy has pics posted on his web site with the results of various ramp tests.

Basically we use 1 or 2 car ramps and check the difference between quads with and without sway bars. I will be doing those tests on my sp in a few minutes. As always, the ramp pics on your web page are quite telling.

 

Based on the tests I have conducted during the last 2 hours I think I will probably keep the sway bar hooked up for most of the riding I do. When I want some more articulation I can just disconnect the sway bar quickly.

All of the testing I just did was concerning articulation with and without the sway bar connected. I used some car ramps. I took many measurements using an angle finder. I took a few pictures. The data are too numerous to post and probably wouldn't be very understandable anyway.

I still need to do some back to back testing off road over the same terrain with and without the sway bar connected. Elkbow already did some of this testing though, so you can search for it if you are interested.


Chris, you wanted to know the articulation difference between the 2004 and 2005 models. My friend has the 2004.5 sp 500 and his articulation with the sway bar connected is less than what mine is. The 2005 sp500 has more articluation because of the softer suspension.

 

Hey jefffoxsr. Heck yea, post the information. Its this type of stuff that gets our brain juices flowing. Some of us don't have the experience you guys have and its just the type of thing to get a discussion going. [img]i/expressions/face-icon-small-smile.gif[/img]
BryceGTX