Difference between stabilizer bar and sway bar

[cworley420]

Could somebody explain the purpose / difference between stabilizer bars and sway bars.

Thanks in advance

-chris worley

 

[Hypedonrc]

sway bars keep the two front/rear tires close to the same extension. Thus keeping the center of gravity lower, so it won't role over on it's side as easy.

Stabilizer bars keep the caster/camber from wobling all over the place, and I don't think are used on buggies. Or rc cars period sense I've never seen a shock on the front of one laying horizontaly between the front tires like on 1:1 trucks.

At least thats how I take it.

 

[niggle]

With great respect, I disagree with hypedonrc's reply to a certain extent.

The terms "sway bar" and "stabilizer bar" seem to be generally used interchangeably, i.e. they both refer to the same type of device. Here in Europe we refer to such devices as "anti-roll bars", which is kind of self-explanatory as to their function (they counteract excessive body roll when cornering).

The horizontally oriented shock absorber device sounds like a steering damper to me, and yes, typically you will never see one of these an an RC car. I guess the servo-saver acts as a crude friction damper anyway?

Originally posted by Hypedonrc
sway bars keep the two front/rear tires close to the same extension. Thus keeping the center of gravity lower, so it won't role over on it's side as easy.

This all depends on the car's roll centre, static COG and camber of the wheel at or near full suspension compression. With a high degree of camber, there is less chance of the outside tyre digging in and hooking the car into a roll. On a car with a high static COG it is possible that the COG will lower in a roll condition.

Bear in mind that not all buggies require a front sway bar and a stiff sway bar increases the likelihood of the inside wheel lifting on cornering, losing traction into the bargain. At the rear end, the oversteer induced by such an arrangement may be desirable and compensate for the lack of traction.

In high grip conditions the inside rear wheel lifting may actually be desirable - i.e. go-kart racing. Karts have a solid rear axle and no suspension - rear axle movement is purely down to flex in the kart chassis/frame. The inside rear wheel lifting in tight corners obviates the need for a differential and reduces understeer.

Hope this helps.

 

[Lessen]

I'm with @niggle, I've always been under the impression that they're all the same thing.

 

[WA2FAST]

I'm with @niggle as well... most people refer to the anti-sway bar as a sway bar or a stabalizer bar. In the end, it does exactly what he says.

 

[Hypedonrc]

I think you are right the horizontal shock on a 1:1 is on the steering. Maybe I got stabalizer bar from steering stabalizer bar.

 

[niggle]

No worries. We're all here to help and not to criticise. All contributions are good in my book.

 

[WA2FAST]

So @cworley420, did any of this answer your question?

 

[olds97_lss]

Well, this is from howstuffworks.com:

Stabilizer bars are part of a car's suspension system. They are sometimes also called anti-sway bars or anti-roll bars. Their purpose in life is to try to keep the car's body from "rolling" in a sharp turn.

Think about what happens to a car in a sharp turn. If you are inside the car, you know that your body gets pulled toward the outside of the turn. The same thing is happening to all the parts of the car. So the part of the car on the outside of the turn gets pushed down toward the road and the part of the car on the inside of the turn rises up. In other words, the body of the car "rolls" 10 or 20 or 30 degrees toward the outside of the turn. If you take a turn fast enough, the tires on the inside of the turn actually rise off the road and the car flips over.

Roll is bad. It tends to put more weight on the outside tires and less weigh on the inside tires, reducing traction. It also messes up steering. What you would like is for the body of the car to remain flat through a turn so that the weight stays distributed evenly on all four tires.

A stabilizer bar tries to keep the car's body flat by moving force from one side of the body to another. To picture how a stabilizer bar works, imagine a metal rod that is an inch or two (2 to 5 cm) in diameter. If your front tires are 5 feet (1.6 meters) apart, make the rod about 4 feet long. Attach the rod to the frame of the car in front of the front tires, but attach it with bushings in such a way that it can rotate. Now attach arms from the rod to the front suspension member on both sides.

When you go into a turn now, the front suspension member of the outside of the turn gets pushed upward. The arm of the sway bar gets pushed upward, and this applies torsion to the rod. The torsion them moves the arm at the other end of the rod, and this causes the suspension on the other side of the car to compress as well. The car's body tends to stay flat in the turn.

If you don't have a stabilizer bar, you tend to have a lot of trouble with body roll in a turn. If you have too much stabilizer bar, you tend to lose independence between the suspension members on both sides of the car. When one wheel hits a bump, the stabilizer bar transmits the bump to the other side of the car as well, which is not what you want. The ideal is to find a setting that reduces body roll but does not hurt the independence of the tires.

 

[Lessen]

I can't wait to see how my new era sway bars work on my DrifTMaxx.(pics in my gallary)

 

[KillerWabbit]

Originally posted by olds97_lss
Well, this is from howstuffworks.com:

...........

Roll is bad. It tends to put more weight on the outside tires and less weigh on the inside tires, reducing traction. It also messes up steering. What you would like is for the body of the car to remain flat through a turn so that the weight stays distributed evenly on all four tires.

..................

HowStuffWorks actually has it backwards. A sway bar REDUCES traction. Increasing or adding a swar bar makes the car more responsive, but at the cost of traction. The bar prevents weight from transfering to the outside wheel that needs it.

My front wheel drive 1:1 car comes stock with a front sway bar and no rear bar at all, so that means it has a natural tendency to understeer. I autocross, so I took the front bar off all together and added a big 22mm rear sway bar. This causes for a good deal of oversteer, especially off-throttle oversteer.. which I like for getting around those cones! By doing that, I've increased front traction and reduced rear traction.

The same goes for springs, shocks and sway bars... stiffer means more responsive, but less grippy.

 

[WA2FAST]

Good article. Good info on it.

 

[cworley420]

I am under the impression that they are the same. I knew the purpose of 'Stabilizer Bars' but, was not sure if a 'Sway Bar' was different.

What brought it all up was a comment by Robriguez in this thread

https://www.rcnitrotalk.com/forum/showthread.php?s=&threadid=14877&highlight=stabilizer

In his list of what to get for the Inferno to upgrade to the Kanai II, one item was "Alum Front and rear stabilizer bars (not sway bars)". The 'not sway bars' comment made me beleive there may be a difference.

-chris worley

 

[shorty]

Here is a link for HPI Savage sway bars. They also have really good information at https://www.hpisavageforum.com/ about the Savage.

 

[shaggybirdman]

i beive arrma uses the 2 shock setup on there limetless they are the front suspension. theres anothe car that uses that setup, but i dont know what it is. its a on road car thing.

 

[burnskevin58]

Could somebody explain the purpose / difference between stabilizer bars and sway bars.

Thanks in advance

-chris worley

Old post I know.
The difference is simple a sway bar will allow a certain degree of sway "Roll/dip" whereas a Stabilizer bar is thicker and has way less sway so way less roll, thus stabilize.

We have sway bars on our r/c cars and trucks, put two sway bars together and you have a stabilizer because it will take more force to sway, roll, dip.

 

[bill_delong]

Although sway bars are common for RC, I have not seen anyone make a steering stabilizer for RC in the same manner I've seen in 1:1 applications.

I only recently got a Class A RV and have been living in it full time over the past year. It's a gasser which is notorious for having horrible ride/sway issues which require upgrades to the steering and suspension to include thicker sway bars to reduce body roll as well as a steering stabilizer which helps the vehicle track straight so you're not constantly having to apply steering input.

The steering stabilizer bar is essentially an extra shock placed on the steering rod to absorb and soften steering response.

In contrast, we sort of have a similar feature in RC with our radios called "Steering Speed" tuning which softens the input from the servo to effectively provide the same effect. I have also seen some people use exponential steering for drag racing to make it easier to track straight by softening steering input.

Aside from that, there are many other mechanical tuning options to explore which can soften steering which negate the need for a steering stabilizer in RC:

 

[Lumikko]

Sway bars are probably the most misunderstood setup component and even the people who correct others make mistakes of their own. So I might as well join the club of people who debunk the myth and get something wrong as well.

Sway bars don’t equalize the load between the outer and inner wheels in a turn. What they actually do is increase load transfer: sway bars put more load on the outer tires and reduce the load on the inner tires.

People understand the physics that makes the inside wheels lift. What most overlook is that it works both ways: when the sway bar is bent to lift the inside wheel, it is pressing the outside wheel down. The force acts both ways.

When the body rolls less, the force reducing the roll must come from increased support on the outside turn and reduced support from the inside turn.

The increase in grip below the outer tires is smaller than the reduction of grip below the inner tires so your overall grip is reduced. That’s why we change to softer sway bars in case the track is low-grip. You get the best overall grip with tires loaded as equally as possible.

So in a nutshell: sway bars increase load transfer when cornering, reduce body roll, increase outside tire grip, but reduce overall grip.

(One could argue that the load transfer will be the same in the end and it’s probably true: for a certain cornering speed and center of gravity the load transfer is what it is. It’s just that a sway bar makes the load transfer ”complete” more quickly than a setup that allows more body roll and a slower load transfer. Raising the roll centers provides instant load transfer, sway bars are a bit more gentle in this regard if you can say that.)

 

[64Corvette]

On a related note it is worth it to check that your sway bars are actually functioning as intended. On my Slash the OEM front and rear bars were clamped tightly by the capture screws and each end was just acting as an independent spring. Confirmed by disconnecting shocks and taking one wheel through full travel had no effect on the opposite wheel. I enlarged the v groove where the bar nests so they would rotate freely and function properly.

 

[Horatio]

Sway bars. Stabilizer Bars. Anti-rollbar.

These are the common terms for them. The first 2 terms are most commonly used in the USA. The latter, is more commonly used in the UK.

I think it's all too easy to get bogged down in the theory and physics behind anti-rollbars, but really there are some very basic things that you can remember for application in the real world.

The first practical thing to remember is that having an anti-rollbar at the rear, the thicker it gets, gives you more grip at the front/greater steering.

The thicker the anti-rollbar at the front, the more grip you get at the rear.

Racing off road on slippery conditions, it's quite common to remove the anti-rollbars at both ends.

Racing on carpet, anti-rollbars are desirable, so as you might expect, they tend to be thicker. Much thicker in fact.

Take a look at my last 2WD A Final, filmed by a co-racer. Mine is the Blue & Pink B7, starting 3rd on the grid, 2nd on lap 1.