Where can I find a "how to" on how to size a sway bar for a rig? I would like some method that takes into consideration spring rates of bike and sidecar suspension, suspension travel, wheel loads, etc. In other words, something a little more definitive than "try a 3/4" and see what happens"
George Ryals
If you find out let me know. Seriously, you can look up a lot of interesting things on the net but they apply to anti swayabrs on automobiles. There is some good research material to be had.....BUT...with a rig there are so many variables invloved it is difficult to pin down what may be best for you. Some people who have done swaybars use stiffer bars than others ...some use longer arms...some use equal length arms, some not.....Swingarm lenghts vary between sidecars, bikes and differnt combinations of these. Track widths vary as does lead of sidecar wheel which in turn may afect the length of the actual bar needed. I have used hollow bars and solid bars....long arms and short..different pickup points on the swingarms and a few other combinations.
All worked with some better than others.
If anyone says you must use this or that size I would respond with the question of 'why'. In other words if someone says they use a 3/4" bar that alone tells you nothing really. How long is it? How long are the arms? What point do they connect to the swingarm of the bike and sidecar? etc etc etc....
Wish I could help more but I cannot tell you much other than to make one up that the bar can be changed
I don't know how useful this is, but It might be of some interest:
http://hometown.aol.com/sidebike00/Page31.html
Jason (jrt) wrote:
I don't know how useful this is, but It might be of some interest:
http://hometown.aol.com/sidebike00/Page31.html
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I think it is very usefull and had posted it here a couple of times, in it's entirity , before. Go back to archived threads on swaybars or torsion bars and there is quite a bit of discussion here on the topic.
Bill Ballou, who wrote the article, is quite an innovator and an excellent machinist.
Also when at Roger's (sidebike 00) site be sure to look at the videos showing the diference between a rig with and without a swaybar.
Thanks Claude. I have read the articles on the HPSC site and the accumulated posts about swaybars on the Yahoo sidecar group. They are very informative. However, I have not found any references that discuss the differing spring rates between the bike and the sidecar suspension. Likewise there has been no discussion about the difference in suspension travel between the bike and the sidrcar. It may not matter at all.
Before I burn up a lot of brain power thinking about this, I wanted to see if someone had examined it already.
Here is a question rattling around:
Is it worthwhile to try to engineer the swaybar setup (unequal length levers on the bar ends)so that 2" of sidecar suspension compression(as in a left hand turn)will cause a like compression of the bike suspension?
George
I would think that working with unequal lengths of Bike swing-arm, Sidecar swing-arm and two different lengths of sway bar lever ends, one could come up with equal 2" deflection on both somewhere in time. I doubt that same equal deflection would be present at 1 1/2" or 3" compression though.
I believe too many variables are present to maintain a constant 1 to 1 ratio at all degrees of suspension compression. One goal (2") seems reachable however.
Am I wrong here?
Like I say: "I'm no engineer, but I've been on a lot of freight trains".
Lonnie
Lonnie you are right, there are a lot of variables involved. I think if,the bike and the sidecar suspension had the same suspension travel you could deal with the differing spring rates of the two with unequal length levers. But, with differing travel, a short lever at the bike(to compensate for spring rate difference) would work against needing to multiply travel by the lever ratio. This is assuming the bike has a good deal more suspension travel than the sidecar.
Of course if you were building a hack or had the "where with all" to modify the sc suspension, the travel could be matched.
I just may be able to talk one of my structural engineer buddies into building a dynamic model of a set up. We can plug in spring rates, travel, and sway bar rates, lever lengths, etc and see what happen when the sc or bike wheel is moved against its suspension and the added resistance due to the load being transfered to the other suspenion.
Stay tuned this might be fun!
GEORGE,
i THINK all that was mentioned is possible....in theory anyhow. It is all about spring rates, leveragfe , motion etc. etc.
I have played with adding extensions to the end of the swingarms to get more 'action' out of the bar...in other words when the sidecar wheel for instance moved ,say, 2" in bump the extension would allow the swaybar to move 4" ....wonder if we could ever make the rig lean INTO turns ?
Also have often wondered if you could even have two seperate swaybars with different ratios for left and right turns (long and short arms) ....haven't made the time to experiment with this yet...LOL.
George, feel free to call me if you wish. I would be happy to share my confusion with you 🙂
(570) 837-5182 or (570) 765-8310
