I run an R1100GS/Ural rig and have started giving some thought to adding a torsion bar to enhance cornering. Looking for options, lessons learned and vendor information. Thanks...Danny
Don't you mean sway bar?
Yep, something that connects the rear suspension on bike to the side car's suspension to reduce cornering lean.
There is some good information over on hpsidecar.com.
Claude Stanley is a regular poster here. Don't know where you are but he is in central PA and can fabricate whatever you might want/need. His web "handle" is "Swaybar", if that tells you anything about his preferences! He is presently fabing a sidecar rig for me which will include both torsion bar suspension and an anti-sway bar.
cstanley@sunlink.net
Sarge
P.S. Wish I could say, "No interest", etc., but I must be the first to admit I am his "Crash Test Dummy". Still, the guy is disgustingly honest.
As far as Sgt. Brown's post goes I did my first torsion bar suspension on a sidecar in the early eighties. Worked well and have done a lot of them since. I have also done quite a few swaybar additions over the years.Note that although both bars are actually torsion bars one is for suspenion and one (the swaybar) is to provide flatter cornering etc and enhances the existing suspenion.
Anyhow,I thought maybe the following on swaybars would be of
interest to you.
One thing for sure about these things..they do make for flatter
cornering which means faster cornering speeds. It is important to make sure the linkage etc is up to the task. The last thing you want to see happen is that you are hard into a turn towards the sidecar...and 'leaning on the swaybar' and it decides to fail. You can imagine what a handfull you would have at that point.
There is a lot of ideas about how long the arms should be, whether
they shoudl be equal length, how stiff the actual bar should be etc
etc etc. The jury is still out and will be for a long time on
this.
I can say that whatever you decide to do make sure the linkage is
set up to allow enough movement of the arms to let the swaybar (anti-
swaybar?) work for you.
Here is a decent write up on swaybars by Bill Ballou.
>>SWAY BAR
By Bill Ballou
It's easier to discuss how a sway bar works on a car and then talk
about the special considerations when installing a sway bar on a
sidecar.
In the basic form, a sway bar is a rod that runs from one side of a
car to the other with equal length arms roughly 90 degrees to the
rod on the ends. Typically the sway bar is mounted in isolastic
bushings mounted near the ends of the bar. With the bushings mounted
to the chassis/body of the car. the equal length arms that are
roughly perpendicular to the bar, are then attached to the
suspension. The best thing to do is to look under a car to get a
closer look how it's done.
A sway bar is a torsion spring. If for example you were driving down
the road in your car and one wheel were to hit a large bump, that
wheel would travel upward against the suspension. In addition, the
torsional stiffness of the sway bar will be added to the
shock/spring combination to resist compressing the suspension. Since
the other wheel didn't hit the bump, the end attached to that side
is essentially fixed. So the wheel that hit the bump is twisting the
sway bar and trying to compress the suspension on the opposite side.
If both rear wheels or front wheels hit a bump at the same time or a
dip in the road, the sway bar does nothing. Since both ends are of
the bar are moving the same amount, the bar just rotates in the
chassis mounts. In another example, when you go around a curve or
corner quickly, the outside suspension begin to compress as
centrifugal force the transfers of weight to the outside wheel. The
sway bar react the same way in this case as well and reduces the
amount of body roll as it tries to keep the vehicle flat. If there
wasn't a sway bar on the vehicle, the suspension would need to be
much stifler to resist the more extreme demands on the suspension.
The beauty of a sway bar is that it only works when it's needed.
Suspension can be more compliant, resulting in a smoother ride when
you have a sway bar. It also does a better job of reducing body roll
better than simply cranking up the suspension. A sway bar helps to
control the darting and diving that can happen as a result of normal
road deviations, high winds or the wind from passing a truck,
swerving to miss something in the road. The effectiveness of a sway
bar is a result of several things but for the most part, the larger
in diameter the sway bar is the stifler it will be and the stifler
the suspension will be when it comes into play. Sway bars certainly
contribute to a safe handling vehicle. I doubt there are any cars
made today that don't have some sort of sway bar. Without sway bars,
cars, truck, and vans would be tipping over regularly,
Thanks Claude and Sarge. Your info has been most helpful. Now that I've a good source for parts I'm into measurement and design...Danny
Danny,
I get 2 months ago a Ural chair from dauntless for one of my R1100GS. After the fun of trying to find the "perfect" setting for the rig, now is time to get more fun during the riding. I guess we are not so many around the country (I'm already in touch with beemerchef) and I would appreciate if you could share your new feeling after installing the swaybar. I still do not really enjoy the curves, right or left, my suspensions may be too old & soft (99 model & 34KM)???.Any way, any info regarding the improvement of the rig's cornering would be more than welcome. I live in NY, if you are around for the MOA rally this summer in Vermont, let me know so we can share our riding feelings. Thanks
Twintwin
Hi TwinTwin... Hi Danny... Claude...
I need to say first that TwinTwin, we have the same combo, has been a primordial help in my installing the "Beast"... Yesterday was my first "into the twistie" experience... been doing 2 wheels for 47 years... and live 20mn's from TWO in the GA Mountains... of course this am I feel like I did 2 hours of Gold GYM!!!... I never knew I has these muscles in these parts of my body!!!...
Claude... I am one of those that will travel wherever needed when something needs to be done... what are your thoughts on an antitorsion bar for the GS/Ural combo... I know that TwinTwin is also interested...
Cost maybe? But even more... what is involved? new welding of brackets for it?
We appreciate all your posts always... and specially the one coming up regarding this question...
You be well...
Ara
Ara,
I have responded to your post within your text below. My responses are in the <<>> marks.
ARA WROTE:
Hi TwinTwin... Hi Danny... Claude...
I need to say first that TwinTwin, we have the same combo, has been a primordial help in my installing the "Beast"... Yesterday was my first "into the twistie" experience... been doing 2 wheels for 47 years... and live 20mn's from TWO in the GA Mountains... of course this am I feel like I did 2 hours of Gold GYM!!!... I never knew I has these muscles in these parts of my body!!!...
<<>>
ARA WROTE:
Claude... I am one of those that will travel wherever needed when something needs to be done... what are your thoughts on an antitorsion bar for the GS/Ural combo... I know that TwinTwin is also interested...
Cost maybe? But even more... what is involved? new welding of brackets for it?
We appreciate all your posts always... and specially the one coming up regarding this question...
You be well...
<<>>
Hi Claude... was just tallking on the phone actually with TwinTwin about it! Thanks for your prompt answer!!! This is an awesome site...
I will definitely call you tonight... have a meeting at 6pm (new restaurant contract finalizing) and should be back around 9pm when I will call you...
Plenty of room here... sometimes... good food (!).
Sometimes life works in mysterious ways! doesn'nt it?
I'll talk to you tonight.
Thanks and be well... Ara
Building Dual sport rigs is starting to get more popular here in the USA,and its long overdue.....
They have alot more experience with these set ups in Europe and some of the designs they have come up with are really cool(in fuction and appearence)!!!!!
There are alot of variables that will make your ride better and a swaybar is definitely one of them. This is the best substitute for an uniframed designed rig which is becoming more popular overseas.
Once you have your swaybar on ther may be other tricks that can be done to make the ride more stable more fun.
Here is a site you should check out......
Sorry that site is in german and just check out the photos.. here is a site where they converted a standard air head Beemer into a world tourer.
This site shows you how they build a rig with a uni frame construction which is the best option..You can also see that the rig has the car tire conversion that Claude mentioned... enjoy
If you like these I have more to offer....
http://www.norseaodyssey.com/The_Bikes/The_Making_of_the_Sidecar/the_making_of_the_sidecar.htm
I am now rigging up a duna to my /2/750. have not ridden it yet,but my engineering back ground can imagine ride problems. if my rig swayed on the hyway would that not be week damping on the outside wheel. there is a large difference in spring rate between the rear wheel and outside wheel.makes me think an antisway bar whoud have little afect. if the bar was attatch to the steering to increase on left turns and decrease on right. could be done with a control cable. is flywheel afect not a problem,whats up with the car tire.John
John,
I am guessing you are refering to the sidecar wheel when you say 'outside wheel'. If so there surely may be a diference in spring rate. These type rigs have a lot going against them from the start. High center of gravity...softly sprung with much travel and many times a somewhat lighter sidecar. Everything we do is a compromise to some extent. So much depends on how much 'compromise' one is happy to live with.A hot street machine will not be real happy off the road no more than a dedicated off road machine will be happy on the pavement. Bridging the gap between dIrt and pavement can be a challenge especially if the rig is intented to be used in both places.
The nice thing about a swaybar is that it can be beneficial on the road and can easily be unhooked for the rougher surfaces. On any rig it can be beneficial really. Individual Spring rates can be softer than what may have been optimal before as the suspensions become linked ,so to speak, with the swaybar. Note that a swaybar can be 'loaded' as well to get different effects if desired.
