What Does A Sway Bar Do?

[BajaRon]

I get a lot of questions about sway bars and what they will actually do for the Spyder. Hopefully, the information below will give you a better idea of how this very critical component works with your shocks and suspension to improve handling and stability.

To understand what my sway bar will do for you, you have to understand what a sway bar does and how your suspension works. It isn’t rocket science, but it is a subject that is widely misunderstood. Sway bars, as with suspension in general, isn’t something that most people are well versed in.

This is in no way an exhaustive treatment of this subject so bear that in mind.

A sway bar (or Anti-Sway Bar) is simply a SPRING which lurks under most vehicles produced today, quietly doing their job with little or no recognition. While the sway bar is a huge component in racing vehicles. It is also critical for the every day driver as it controls aspects of handling and control that no other component can.

There are several suspension components that work together to give us a safe, controlled and comfortable ride. Improve any one of them and you will likely see immediate improvement in the area(s) that are affected by that component. It would be foolish for BRP to build the best possible suspension for our Spyders as that would be very expensive and not necessarily appreciated by every customer.

Stock suspension on our Spyders is adequate. Yet there is a great deal of improvement to be had if the owner would like better, more controlled handling.

What we are addressing in this explanation are the effects of centrifugal force (lean angle in a turn) or any side forces (wind, buffeting when passing a large truck, etc.) and how to best counteract these forces, most notably in the case of our Spyders, excessive lean.

There is much more to our suspension, shocks in particular, than just countering centrifugal force. But for this explanation I am only discussing lean angle aspects.

My drawings are crude, but hopefully helpful. Art is not my strong suit!

EffectsShockSwayBar.jpg

1st Picture
This depicts the Spyder going straight ahead without Shocks or Sway Bar. Just 1 A-Arm is shown on each side to keep things simple. The sway bar has zero effect running straight ahead (unless there is a cross wind or buffeting as in passing a large truck on the freeway. Shocks also have little effect when running straight ahead other than to absorb any bumps in the road. Of course the springs on the shocks hold the Spyder up.

2nd Picture
Suspension and body of the Spyder reacts to Centrifugal force (Yellow Arrow) causing the body of the Spyder (Blue Box) to lean to the outside of the turn (exactly the opposite of lean angle on 2 wheels where you must lean to the inside of the turn.) The Spyder does not compensate for centrifugal force. Instead, it attempts to manage it. How well a Spyder manages centrifugal force depends on many factors including the shocks and sway bar. On 2 wheels, centrifugal force must be perfectly balanced. This is done by leaning into the turn.

3rd Picture
Shock springs provide equal down force (Green Arrows) holding your Spyder up. Stiffer spring setting will raise the Spyder. A weaker spring setting will lower your Spyder.

4th Picture
Inside Shock - During a turn the Shock on the inside of the turn (away from the lean angle) extends. This lengthens the spring and reduces down force to that wheel. Though down force is reduced, this inside shock spring is still contributing to lean angle by pushing down on the suspension and raising the high side of the Spyder body, thus adding to lean angle to some degree. This happens until the inside wheel is lifted off the ground. At this point the inside shock has no effect on lean angle.

Outside Shock – While turning, the Outside Shock is compressed reducing spring length which greatly increases down force to that wheel. This increased down force resists lean angle.

The greater the lean angle, the more pronounced both of these shock spring effects are. Here are some basic rules of thumb regarding shock spring effects.

Lower spring Pre-Load setting, lower ride height, increased lean angle in turns, softer, more compliant ride.

Higher spring Pre-Load setting, increased ride height, less lean angle in turns, harsher, less compliant ride.

5th Picture
Remember, the Sway Bar is a Spring attached at 2 points on the frame (Blue Box). The ends of the sway bar are attached to the A-Arms. When going straight ahead the Sway Bar has no effect on the suspension what-so-ever. Therefore, a stiffer sway bar cannot effect the harshness or softness of your ride. The sway bar does not hold your Spyder up, so changing the sway bar will not affect ride height or front end alignment.

6th Picture
A sway bar WILL NOT eliminate lean. You actually need lean to make everything go smoothly. It is the AMOUNT of lean that you want to better control with the sway bar.

A sway bar is simply a straight spring. As with all springs, it is designed to flex with increasing resistance to increased force applied. You can see in this exaggerated picture that a great deal of stress is being applied to the sway bar due to the lean angle of the Spyder body (Blue Box). The sway bar is attached to the frame at 2 points. It does not actually bend as depicted, but it is difficult to show how this torsion spring works with my limited skills in diagramming.

The Sway Bar is always working to stay straight. As the lean increases the Sway Bar applies increasing force to each A-Arm in its attempt to remain straight. Using leverage created by the angle of the A-Arms, the Sway Bar applies force to the Spyder Body (Blue Box) in the opposite direction to the lean created by side force.

Once you ride a Spyder with a Custom Performance Sway Bar, you won't need to know any of this because you will be able to feel exactly what I'm talking about every time you encounter a situation where your Spyder used to lean too much.

I sincerely hope this helps! Being well informed is the best tool any Spyder owner can have in their tool box.

[Kratos]

Thanks for this detailed answer to a drawn out question.

[Wildrice]

Thanks for this detailed answer to a drawn out question.

Custom Dynamics Led Project titled "Knight Rider".

Good Video---Next--another UFO sighting on the freeway :-)

[Bob Denman]

Thanks for the explanation!
But a question: If you hit a bump with one wheel; does that linking of the two sides of the bike via the anti-sway bar then result in a "stiffer" suspension?

[Lamonster]

So you're saying the new swaybars will be red?

[NancysToy]

One more thing to point out to some people who may wonder, or think otherwise. The Spyder already has a swaybar (or more correctly anti-swaybar). The effects of the swaybar can be enhanced by installation of an aftermarket, performance swaybar, just as it can be by installing aftermarket, performance shocks. All suspension systems on production vehicles are compromises. Compromises on springs and damping (coil-over shocks on the Spyder), compromises on swaybar stiffness, and compromises on performance vs. production costs. Many rides never feel the need for performance components, or may prefer comfort over performance, and the factory stuff suits them fine. Others don't want the ride harshness that may come with the package, while some may not have the knowledge or skills to select performance components in such a way that they work well together. For those of us that may have special needs, such as doing a lot of mountain riding or carrying a heavy load, performance items like Ron's swaybars or some Elka shocks may be just the answer. The Spyder isn't deficient in the handling department (except for maybe the OEM 2010 RT), but if you feel a need for more than the factory offers, aftermarket componenets may be for you. We don't all need them, but those that want them are glad they are available.

[Netminder]

So you're saying the new swaybars will be red?

That's too funny!!

[Bob Ledford]

Years ago I tried to get someone to explain it to me. But I never could grasp the thread of data. Now I understand the concept. Thank you Ron! PS your graphics are pretty decent to but I wonder if BRP knows the 14 bars are supposed to be RED?

[Dan_Ashley]

Thank you, Ron.
I purchased your bar on the advice of members in my Spyder Ryders of America chapter. My complaint was not the twisties, I lust lean like on a quad...my complaint was the super high cross winds we get on interstate 10, just outside of Palm Springs...cross winds sometimes exceed 50mph, and the road wander was annoying me. I will install the bar this coming weekend and report back what changes I perceive. My club says the changes will be significant.

thank you for the rudimentary suspension tutorial.

[Ivorspyder]

Thanks for the explanation.It certainly has given me a much better understanding of what the function of the sway bar is.


Ivor

[Bob Denman]

Lamont,
You saw that too?

[BajaRon]

Thanks for the explanation!
But a question: If you hit a bump with one wheel; does that linking of the two sides of the bike via the anti-sway bar then result in a "stiffer" suspension?

I was trying to keep it simple! I hope this dosn't turn into a 'Try to Stump BajaRon' contest....

The sway bar will resist any movement that is not equal at both wheels. Slightly at first and more forcefully as the deflection increases. This will be true whether one wheel tried to go down (drop into a pothole) or up (over a bump).

The shock on that side will also affect action to that wheel.

So, technically speaking, the sway bar would give you a 'Stiffer' suspension in this senerio. But the effect would be minimal and less than what the shocks would be doing at the same time.

So you're saying the new swaybars will be red?

Only if your shocks are Green and your frame is Blue!

[shelbydave]

Thanks for the explanation!
But a question: If you hit a bump with one wheel; does that linking of the two sides of the bike via the anti-sway bar then result in a "stiffer" suspension?

I was trying to keep it simple! I hope this dosn't turn into a 'Try to Stump BajaRon' contest....

The sway bar will resist any movement that is not equal at both wheels. Slightly at first and more forcefully as the deflection increases. This will be true whether one wheel tried to go down (drop into a pothole) or up (over a bump).

The shock on that side will also affect action to that wheel.

So, technically speaking, the sway bar would give you a 'Stiffer' suspension in this senerio. But the effect would be minimal and less than what the shocks would be doing at the same time.

But the added feeling of "stiffness" is much more desirable than the loss of control feeling you get when your suspension goes all "whoppyjawed"

[asp125]

Stiffer, softer... are the kids asleep? what kind of forum is this anyway!??

[shelbydave]

Stiffer, softer... are the kids asleep? what kind of forum is this anyway!??

This reminds me of the jokes that were flying about when Viagra sponsored Mark Martins car a few years back..

[Ride Master]

Red is fine. You gave me a headache. I think I'm in a coma.

[Bob Denman]

But the added feeling of "stiffness" is much more desirable than the loss of control feeling you get when your suspension goes all "whoppyjawed"

Is that a NASCAR term??

Ron,
I didn't mean to throw you a curve... And the effect that I mentioned is; of course, absent if you hit a bump or hole with both front wheels...

[BajaRon]

Ron,
I didn't mean to throw you a curve... And the effect that I mentioned is; of course, absent if you hit a bump or hole with both front wheels...

Not a problem. Anytime you cover a protion of a larger subject like this there are always questions about the parts that are left out. Like Scotty's adding that there is already a sway bar on the Spyder just like there are Shocks on the stock Spyder.

This was not meant to say that everyone should rush out and buy a sway bar, shocks, or any other suspension part for their Spyder. I was hoping to give people an idea of what they can expect from changing to a stiffer sway bar so they can decide if this is something that would benefit them or not.

[Cuffs19]

One more thing to point out to some people who may wonder, or think otherwise. The Spyder already has a swaybar (or more correctly anti-swaybar). The effects of the swaybar can be enhanced by installation of an aftermarket, performance swaybar, just as it can be by installing aftermarket, performance shocks. All suspension systems on production vehicles are compromises. Compromises on springs and damping (coil-over shocks on the Spyder), compromises on swaybar stiffness, and compromises on performance vs. production costs. Many rides never feel the need for performance components, or may prefer comfort over performance, and the factory stuff suits them fine. Others don't want the ride harshness that may come with the package, while some may not have the knowledge or skills to select performance components in such a way that they work well together. For those of us that may have special needs, such as doing a lot of mountain riding or carrying a heavy load, performance items like Ron's swaybars or some Elka shocks may be just the answer. The Spyder isn't deficient in the handling department (except for maybe the OEM 2010 RT), but if you feel a need for more than the factory offers, aftermarket componenets may be for you. We don't all need them, but those that want them are glad they are available.

I'm buying a 2010 RT. is there something i should know about the handling?

[flybuddy]

I'm buying a 2010 RT. is there something i should know about the handling?

The model years are fairly similar except that the shocks on the 2010 models were too soft and BRP upgraded them in 2011. The best upgrade for you would be the Elka Shocks or to at least upgrade to the 2011 or 12 OEMs. Lots of folks probably have a set laying around as a lot of us have upgraded to Elkas.

[Cuffs19]

The model years are fairly similar except that the shocks on the 2010 models were too soft and BRP upgraded them in 2011. The best upgrade for you would be the Elka Shocks or to at least upgrade to the 2011 or 12 OEMs. Lots of folks probably have a set laying around as a lot of us have upgraded to Elkas.

Good to know, thanks!

[PatriotRider]

I just purchased a 2010 RT

and am following the wisdom here closely. I wish to enjoy, safely somewhat reasonably spirited riding in the twisties with my wife aboard (I wasn't healthy enough for a number of years to continue to take her along on 2 wheels, so this is a big deal). We are each at least 225ish pounds. A BajaBob sway bar is at the top of my purchase list. However, I am disabled, supporting a family of 4 hoomans & 4 hounds, so quite financially challenged.

Is there any reason to also change the links?

The price of Elka's must be high...sounds like I should post a WTB 2011 or 12 OEM shocks as a reasonable upgrade.

does this sound right for me ???

The model years are fairly similar except that the shocks on the 2010 models were too soft and BRP upgraded them in 2011. The best upgrade for you would be the Elka Shocks or to at least upgrade to the 2011 or 12 OEMs. Lots of folks probably have a set laying around as a lot of us have upgraded to Elkas.

[Highwayman2013]

I did not change the links on my 2012 at first, the metal ones were not available. I ran the RT for two years with the plastic links and Bajaron swaybar with no problems. I did upgrade to the metal links earlier this year as a peace of mind thing. The metal links came out in 2013 in response to a bad batch of plastic links failing. Read here:
http://www.spyderlovers.com/forums/s...rs-amp-Helmets

[modagwood]

does ron have any conpetors who build sway bars?

[MikeinGA]

I get a lot of questions about sway bars and what they will actually do for the Spyder. Here is my feeble attempt at giving a reasonable and, I hope, simple explination.

To understand what my sway bar will do for you, you have to understand what a sway bar does and how your suspension works. It isn’t rocket science but it is a subject, like oil, where there is a lot of misunderstanding. It just isn’t something that most people are familiar with.

This is in no way an exaustive treatment of this subject so bear that in mind.

A sway bar (or Anti-Sway Bar) is simply a SPRING which lurks under most vehicles produced today, quietly doing their job with little or no recognition. The racing enthusiast is quite familiar with sway bars as they are one of the key components to getting around corners quickly and adding control aspects to the vehicle that no other component can.

There are several suspension components that work together to give us a safe, controlled and comfortable ride. Improve any one of them and you will likely see immediate improvement in the area(s) that are affected by that component. It would be foolish for BRP to build the best possible suspension for our Spyders as that would be very expensive and not necessarily appreciated by every customer.

Stock suspension on our Spyders is adequate. Yet there is a great deal of improvement to be had if the owner would like better, more controlled handling.

What we are addressing in this explination are the effects of centrifugal force (lean angle in a turn) or any side forces (wind, buffeting when passing a large truck, etc.) and how to best counteract these forces, most notably in the case of our Spyders, excessive lean.

There is much more to our suspension, shocks in particular, than just countering centrifugal force. But for this explanation I am only discussing lean angle aspects.

I'm sure your 2nd grade student could do better with Crayons but please, be kind!


1st Picture
This depicts the Spyder going straight ahead without Shocks or Sway Bar. Just 1 A-Arm is shown on each side to keep things simple.

2nd Picture
Suspension and body of the Spyder reacts to Centrifugal force (Yellow Arrow) causing the body of the Spyder (Blue Box) to lean to the outside of the turn (exactly the opposite of lean angle on 2 wheels where you must lean to the inside of the turn.)

3rd Picture
Shock springs provide equal down force (Green Arrows) holding your Spyder up. Stiffer spring setting will raise the Spyder, lower spring setting will lower your Spyder.

4th Picture
Inside Shock - During a turn the Shock on the Inside of the turn (away from the lean angle) extends. This lengthens the spring and reduces down force to that wheel. Though down force is reduced, this inside shock spring is still contributing to lean angle by pushing down on the suspension and raising the high side of the Spyder body, thus adding to lean angle to some degree. This happens until the inside wheel is lifted off the ground. At this point the inside shock has no effect on lean angle.

Outside Shock – While turning, the Outside Shock is compressed reducing spring length which greatly increases down force to that wheel. This increased down force resists lean angle.

The greater the lean angle, the more pronounced both of these shock spring effects are. Here are some basic rules of thumb regarding shock spring effects.

Lower spring Pre-Load setting, lower ride height, increased lean angle in turns, softer, more compliant ride.

Higher spring Pre-Load setting, increased ride height, less lean angle in turns, harsher, less compliant ride.

5th Picture
Remember, the Sway Bar is a Spring attached at 2 points on the frame (Blue Box). The ends of the sway bar are attached to the A-Arms. When going straight ahead the Sway Bar has no effect on the suspension what-so-ever. Therefore, a stiffer sway bar cannot effect the harshness or softness of your ride. The sway bar does not hold your Spyder up, so changing the sway bar will not affect ride height.

6th Picture
A sway bar WILL NOT eliminate lean. You actually need lean to make everything go smoothly. It is the AMOUNT of lean that you want to reduce with the sway bar.

A sway bar is simply a straight spring. As with all springs, it is designed to flex with increasing resistance to increased force applied. You can see in this exaggerated picture that a great deal of stress is being applied to the sway bar due to the lean angle of the Spyder body (Blue Box). The sway bar is attached to the frame at 2 points. It does not actually bend as depicted, but it is difficult to show how this torsion spring works with my limited skills in diagramming.

The Sway Bar is always working to stay straight. As the lean increases the Sway Bar applies increasing force to each A-Arm in its attempt to remain straight. Using leverage created by the angle of the A-Arms, the Sway Bar applies force to the Spyder Body (Blue Box) in the opposite direction to the lean created by side force.

Once you ride a Spyder with a Custom Performance Sway Bar you won't need to know any of this because you will feel exactly what I'm talking about every time you encounter a situation where your Spyder used to lean too much.

I sincerely hope this helps! Being well informed is the best tool any Spyder owner can have in their tool box.

Don't worry about all the tech stuff. His anti-sway bar works. The first time I road my 2011 RS-S after the installation was great, less body lean and it made my Spyder easier and more fun to ride. It's the best upgrade I have made so far and Lamonster my anti-sway bar is RED.

Mike