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Torsion Bar

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(@Beemerchef)
Posts: 762
Prominent Member
 

You are a wize man Mark and I admire that... so right... we all have our limitations... I work in Downtown Atlanta and I see the Armani suits and the 75+K cars passing by... followed by hefty montly payments!!!... I smile...
I live at the foothills of the best twisties this country has to offer... from here to NY including TN, NC, SC, VA... my only reason for living here including plentiful of primitive camping... the torsion bar has elevated my riding to what I feel is a safer mod... I will always maintain that it should be a standard on cars... so is the TILT... a comfort process that I could not live without now... they are little affordable (I am single...) compensations since I do not drink or do drugs! (my favorite saying!...).
Hope to see you down the road... in the meantime take good care of your family, they do deserve you.
Be well. Ara


 
Posted : April 19, 2006 2:30 pm
(@Anonymous)
Posts: 0
 

Thanks to all for the responses. The opinions and info have been extremely helpful. Since I am still in the planning stage for my sidecar rig, the advise has given me a better idea as how best to proceed. With that said, my current plan is to pursue a Ural dual-sport rig similar to Beemerchef's. I will hold off on a leading link modification for the time being, but I will probably add a sway/torsion bar fairly quickly.

Now if I can only find a suitable tug. 🙂

Mike


 
Posted : April 21, 2006 4:59 am
(@Mark-in-Idaho)
Posts: 346
Reputable Member
 

Mike,
Take a look at the KTM bikes. They cost less than the BMW's but still have a good parts and service network. If I had deep pockets, I would buy the 900 for the Idaho dirt roads. Half the state is Federal land(Forest Service, BLM, or wilderness designation.) Therefore, half the roads are dirt.


 
Posted : April 21, 2006 5:25 am
(@claude-3563)
Posts: 2481
Famed Member
 

Beemerchef wrote:
>>I live at the foothills of the best twisties this country has to offer... from here to NY including TN, NC, SC, VA... my only reason for living here including plentiful of primitive camping... the torsion bar has elevated my riding to what I feel is a safer mod... I will always maintain that it should be a standard on cars... so is the TILT... a comfort process that I could not live without now... they are little affordable (I am single...) compensations since I do not drink or do drugs! (my favorite saying!...).<>I will hold off on a leading link modification for the time being, but I will probably add a sway/torsion bar fairly quickly.<<

Just let me clear the air here before some new readers get confused over the term 'torsion bar'. In the cases here what is being spoken of is a 'swaybar' and not a 'torsion bar' as related to usage. A 'swaybar' connects the bike rear suspension to the sidecar suspension and creates a better handling rig by providing more stable and flatter cornering.It can be easily unhooked when off road. This is what beemechef has been referring to as a 'torsion bar'. (technically it is a torsion bar but not used as one).
When the term 'torsion bar' is used as related to suspension it is actually a suspension member or a spring so to speak. Many cars have used torsion bar suspensions for years (VW, Subaru, Dodge etc). Motorvation sidecars have used torsion bars for suspension for years on their Formula II sidecar. They work very well for sidecars. I have done many torsion bar conversions to various sidecars that did not come with them. Velorexes in particuler work great with a torsion bar conversion. I think the first one I did weas back in '86 or maybe before.
There is a two fold benefit a torsion bar suspension. One, you have a cost efective suspension that is easliy tuned for softer or harder ride. Two, you get a tilt adjuster built in that is not an extra cost to you. Not a bad bang for the buck.
Yes, a torsion bar suspension can be used in conjunction with a swaybar setup but the two are seperate intities.


 
Posted : April 22, 2006 2:17 am
(@Anonymous)
Posts: 0
 

Hi,
I have been reading your discussion on torsion bars. I have a KZ1300 Kaw./EML rig. The steering on this rig is super sensitive, so much so, that there is little feeling in the handle bars, and you do most of the steering with body english. This rig has, as you probably know an Earls type fromt suspention, and very narrow handle bars, from a BMW GS model. The steering is so sensitive that the rig will follow road grooves, and if you put any pressure on the handle bars it gets skitterish. You must let all pressure off the handle bars, in this situation, and the rig will correct it's self. I wonder what the steering would be like with a torsion bar also? I have just started to read about the torsion bar and do not even know what one looks like. Is there any input to this?
Thanks.
Chubbo


 
Posted : April 30, 2006 8:38 am
(@claude-3563)
Posts: 2481
Famed Member
 

Chubbo,
Go back to the early part of this thread and see the post with the writeup by Bill Ballou.
I think your steering concerns are simply a matter of a much reduced trail, the narrow bars and to a lesser degree the car tire wanting to follow the imperfections in the road. If this rig is new to you then you may get more used to it as you go. If not increasing trail slightly may help some. Also playing with tire pressue of the front tire may help.
A swaybar is more so used to help a rig corner flatter and provides more secure handling. It really is not something that will directly help steering.


 
Posted : April 30, 2006 9:13 am
(@Hack__n)
Posts: 4720
Famed Member
 

Chubbo,
Flat tread autombile radial tires have a tendency to follow road seams and even rain grooves. On some rigs the steering pressure needed to overcome this will cause the tire to "hop" over the seam or groove and with very narrow handlebars this can sometimes even cause a tank slapper of a shimmy. Usually a steering damper will control this, but the addition of wider bars will allow more sensitive control by slowing your steering input somewhat.

Lonnie


 
Posted : April 30, 2006 11:14 am
(@claude-3563)
Posts: 2481
Famed Member
 

For a picture of a swaybar click on live link below. It is th elong silver colored member running across the sidecar frame on an angle. The parts on the ends that run from the bar to the link areas are called 'arms'. Many of us build them in difent ways and mount them diferently but the idea is the same...linking the sidecar swingarm to the motorcycle swingarm through a member that acts as a torsional spring. This makes for a more stable handling rig and allows flatter cornering. It also will automatically compensate to a degree for road camber changes , sidecar loading etc. It will work with a tilt adjustor or without one. On a dual sport rig one end can be easily unhooked to let the bar 'float' in it's mounting if going into the really rough stuff. On most dirt roads it can be left hooked up and will allow one to slide through the turns wih more stabilty than without it.
It will do a lot more on most all rigs than changing to aftermarket shocks and or springs and the cost less. The cost /value ratio is very high on a swaybar installation compared to many things.


 
Posted : April 30, 2006 7:15 pm
(@outfit)
Posts: 65
Trusted Member
 

claude. After beefing-up the sidecar suspension my fear now is that when cornering away from the sidecar at speed (right-hander's),I dont want the motorcycle to climbe above the sidecar.Would the swaybar idea prevent this from happening. Left-hand bend's are not a problem as I get a feel of what's going-on, but right hander's do prove a problem as I think the feed back is little.
Safe riding Karl


 
Posted : May 1, 2006 2:10 pm
(@claude-3563)
Posts: 2481
Famed Member
 

Originally written by outfit on 5/1/2006 7:10 PM

claude. After beefing-up the sidecar suspension my fear now is that when cornering away from the sidecar at speed (right-hander's),I dont want the motorcycle to climbe above the sidecar.Would the swaybar idea prevent this from happening. Left-hand bend's are not a problem as I get a feel of what's going-on, but right hander's do prove a problem as I think the feed back is little.
Safe riding Karl

On some rigs the feeling of th erear wheel getting light or trying to lift when turning away from the sidecar is a very real concern. This was th ecase on the two GS rigs that recently had swaybars put on them. Does the swaybar help? Yes, by quite a bit it does. The idea is that when the sidecar suspension begins to compress on a turn away from the sidecar the swaybar tries to make the motorcycle suspension compress as well.
Note that running more wheel lead on the sidecar will also help the situation.


 
Posted : May 1, 2006 2:41 pm
(@outfit)
Posts: 65
Trusted Member
 

claude. Thank's for the reply,I guess I'd better start activating some used-up brain cell's as to how I'd connect up.
The sidecar wheel lead suite's me fine at around 8inch, it's just when the sidecar suspension goes down, I dont have any imput as to when the motorcycle rear wheel begin's to get light.
I've been riding the thing for 15yrs now and it's alway's been in the back of my mind "what if the rear wheel of the motorcycle suddenly goes light".
Anyway, enough of this rambleing and thank's for the advice
Safe riding Karl


 
Posted : May 2, 2006 6:40 am
(@claude-3563)
Posts: 2481
Famed Member
 

Karl wrote:
>>claude. Thank's for the reply,I guess I'd better start activating some used-up brain cell's as to how I'd connect up.
The sidecar wheel lead suite's me fine at around 8inch, it's just when the sidecar suspension goes down, I dont have any imput as to when the motorcycle rear wheel begin's to get light.
I've been riding the thing for 15yrs now and it's alway's been in the back of my mind "what if the rear wheel of the motorcycle suddenly goes light".<<<<

Karl,
All outfits have what has become known as 'tip over lines'. There is a tip over line between the front and rear wheel, between the sidecar and rear wheel and between the sidecar wheel and front wheel. These are imaginary lines that define where the pivot point, so to speak, would be if the sidecar rig tipped over.
In a turn away from the sidecar the tip over line between the sidecar wheel and the front wheel of the bike is the one we would be concerned with. You said you were satisfied with 8" of lead but are concerned with the rear wheel of the bike feeling like it is coming up when turning away from the sidecar. Yes, a swaybar would help but increasing the lead would help a lot too. More lead moves the tip over line to be more to your advantage in turns away from the sidecar. 8" is minimal for most rigs. If you have a light bike and heavy chair it way be very minimal.
Think of it this way. If the sidecar wheel was even with the front wheel of the bike (hypothetical of course) think how stable the rig would be in a turn away from the sidecar. Very stable right? So, where is the best compromise? Maybe if you increased your lead to say 10" or even 12" you would see a world of difference and maybe not even consider installing a swaybar.
Just food for thought,


 
Posted : May 2, 2006 2:02 pm
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