Anyone know if the OEM Swaybars on F3's are stiffer than RT's?

[Kingz]

I installed the Baja Ron sway bar on our 2020 RTL shortly after buying it and really like it. I recently purchased a 2024 F3 and was planning on installing the bar on it also. But after riding a few hundred miles it seems to feel better than the stock 2020 RT did. I haven’t done a lot of hard twisty riding yet, but my question is - does anyone know if they put a stiffer bar on the F3 from the factory?

 

[BajaRon]

I installed the Baja Ron sway bar on our 2020 RTL shortly after buying it and really like it. I recently purchased a 2024 F3 and was planning on installing the bar on it also. But after riding a few hundred miles it seems to feel better than the stock 2020 RT did. I haven’t done a lot of hard twisty riding yet, but my question is - does anyone know if they put a stiffer bar on the F3 from the factory?

The sway bars have not changed since the redo in 2013. And even then, the functional action of the original sway bar strength was maintained in the redesign, though in a different configuration. We test each new production year sway bar against the 2013 RT bar that we have and there has been no change.

However, the F3 is lighter, has a different seating position, and has a lower center of gravity compared to the RT. Though the F3 has a lighter sway bar than the RT, the other factors are significant. You're comparing a sports car to a Cadillac. They are not going to handle the same.

 

[Kingz]

Thanks for the info! I like the idea of getting a thousand miles on before changing as you mentioned on the phone.

 

[BajaRon]

Thanks for the info! I like the idea of getting a thousand miles on before changing as you mentioned on the phone.

I think the 1,000 mile request is a good rule of thumb. We want you to be happy with our product. Being familiar with your machine is a big step in that direction. You need to know what it did before to be able to compare after a suspension upgrade.

Personally, I'm an F3 guy. I have never wanted to own an RT. My wife does not like to ride so I'm always 1-up. If my wife ever changes her mind, though. I'll be on an RT in a heartbeat!

Enjoy! The F3 is a fine machine. One thing to note is that there have been very few changes (other than cosmetic) to the F3 over the years. That right there tells you something.

 

[johnv50]

I put Baja Rons anti sway bar on my F3T and it made a huge difference.
Shortly after I added Vredestein Quatracs and that resulted in another level of performance.
I am a Happy Camper !!

johnv

 

[T.P.]

I Got my 2017 PB1 F3T from PITBULL powersports of Springfield, MO in February 2017
it had a RT takeoff bar on it from the dealer. Later I would pick up a Ron bar and then when he came out with the Ultra Bar I picked up one of those.
A good investment if you ride the whole road at top speed.
T.P.

 

[troop]

I Got my 2017 PB1 F3T from PITBULL powersports of Springfield, MO in February 2017
it had a RT takeoff bar on it from the dealer. Later I would pick up a Ron bar and then when he came out with the Ultra Bar I picked up one of those.
A good investment if you ride the whole road at top speed.
T.P.

I also put the BR Ultra bar on my 2022 RT S2S. I have had to snug it up a couple of times to eliminate some "clunk" noise. I think if I did it again, I'd order the original version.

 

[BajaRon]

I also put the BR Ultra bar on my 2022 RT S2S. I have had to snug it up a couple of times to eliminate some "clunk" noise. I think if I did it again, I'd order the original version.

If installed correctly, you'll find no need to snug up connections. The Original and Ultra fulfill 2 different suspension needs. Each person should choose the bar kit that best fits their riding style to get the most out of this upgrade.

It sounds like you're bushing bolts were not tightened sufficiently. There should be no gap in the bushing slit at the point where the bushing bolt passes through it. That bolt needs to be tightened until the gap disappears and a slight dimple begins to form.

Since both sway bar kits use the same bushings, the Original bar will do the same thing if not tightened correctly.

Hope this helps.

 

[troop]

If installed correctly, you'll find no need to snug up connections. The Original and Ultra fulfill 2 different suspension needs. Each person should choose the bar kit that best fits their riding style to get the most out of this upgrade.

It sounds like you're bushing bolts were not tightened sufficiently. There should be no gap in the bushing slit at the point where the bushing bolt passes through it. That bolt needs to be tightened until the gap disappears and a slight dimple begins to form.

Since both sway bar kits use the same bushings, the Original bar will do the same thing if not tightened correctly.

Hope this helps.

So far, so good.

 

[BajaRon]

So far, so good.

If you like, send me a picture of the bushing slit on both sides. We'll do whatever is necessary to get this right. We want you to be happy with the kit.

 

[troop]

If you like, send me a picture of the bushing slit on both sides. We'll do whatever is necessary to get this right. We want you to be happy with the kit.

Thanks Ron. I actually snugged up both bushings and control arms just before winter storage. I'll send some pictures in a few months after the Wisconsin hibernation

 

[pauly1]

Several disqualifiers: I ride solo on an F3-S and an F3-T. My weight, in gear, is 170-175 lbs.

Torsion (anti-sway) bar performance is based on the diameter of the bar and the lever-arm between the centerlines of the main bar to the linkage bolt. It doesn't make any difference as to the steel chosen: the flex modulus remains constant but the yield point of the steel is dependent on steel type and hardness. The stock RT bars are about 40% more stiff than the F3-S bars. Another point to consider is how stiff do you want it?

Consider stiff to the point of being solid, left to right. You still have suspension. But the result is to lose "independent" suspension: any pot hole/bump will drop/lift the associated wheel, tilting the entire Spyder, resulting in a lot of upper torso and head movement. As the RT sits higher, that movement would be more severe. Indeed, the machine will be more flat going through a corner, arguably at the cost of rider comfort.

 

[BajaRon]

Several disqualifiers: I ride solo on an F3-S and an F3-T. My weight, in gear, is 170-175 lbs.

Torsion (anti-sway) bar performance is based on the diameter of the bar and the lever-arm between the centerlines of the main bar to the linkage bolt. It doesn't make any difference as to the steel chosen: the flex modulus remains constant but the yield point of the steel is dependent on steel type and hardness. The stock RT bars are about 40% more stiff than the F3-S bars. Another point to consider is how stiff do you want it?

Consider stiff to the point of being solid, left to right. You still have suspension. But the result is to lose "independent" suspension: any pot hole/bump will drop/lift the associated wheel, tilting the entire Spyder, resulting in a lot of upper torso and head movement. As the RT sits higher, that movement would be more severe. Indeed, the machine will be more flat going through a corner, arguably at the cost of rider comfort.

I do not understand your statement that 'It doesn't make any difference as to the steel chosen'. The function of a sway bar (torsion bar) is based on resistance to deflection. Different spring steel compounds have varying ability to resist deflection. They also have varying ability to resist fatigue so as to maintain their original integrity. So bar diameter and arm length are not the only determining factors.

Our original GS/RS sway bar is the same diameter as the OEM bar. Yet is much more resistant to deflection. We tested several different spring steel compounds before settling on the one we use. The higher strength allows us to keep a smaller diameter while still achieving the desired result.

You are correct that a sway bar can be too stiff. And If you are spending a good deal of time riding over large potholes at speed, a sway bar upgrade might not be in your best interest as you're essentially traversing an off road surface.

 

[TheMariner]

As far as I'm aware, Flex Modulus is cross section-dependent more than material-dependent as it is a measure of resistance to bending. In action, there will be some bending of the sway bar between its 2 mounts due to the application of offset loads, the main forces applied will be torsional.

In a bar under Torsion, the measure of its cross-section is divided by its length so in the case of a sway bar, each relatively big increase in Ø of a mm is somewhat negated by the much larger ( 600x ?) length of the item. However, Shear Modulus (Modulus of Rigidity) of the material has a direct influence on its Torsional Resistance as it is a multiplier.

As an extreme example consider 2 sway bars identically sized, 1 in Steel and the other in Aluminium. We know the Aluminium one will offer almost no benefit and this is because it has a 3x lower Shear Modulus.

 

[BajaRon]

I confess to not having researched our sway bar project in the scientific, mathematical realm. What we did was fabricate identical sway bars out of 5 different spring steel compounds. Then we mounted them on a jig which captured one arm and added length to the other with a rigid pipe. (About 18" long). We then attactached a weight to the end of the extended arm and measured the amount of deflection. The extension exaggerated this measurement, of course. But it was a worthwhile exercise which we felt gave us real world results and not theoretical ones.

We also included the OEM sway bars in our tests. Which matched closely the results we got with the lowest strength bar material we used as a base line. This didn't surprise us as this is the material used by most since it's the least expensive, easily fabricated, and you only need to adjust the diameter to get the desired resistance.

Of course you are correct that the shorter the torsion length, the more small changes make a great difference. For sway bars, the Spyder's is quite short.

 

[pauly1]

First, Ron, your empirical testing is better than any textbook study. Many have tried your torsion/anti-sway bar and many prefer them to the OEM torsion bars.

To clarify, though, the steel type doen't affect the spring rate. That's an inherent property of the steel listed as E, or Young's Modulus, or flex modulus. The spring rate is relatively consistent across steel types @ 30,000,000 psi. The steel type and hardness affect the yield point of the steel alloy. For a spring to function, deflect and return to the original position, the flexure must be in the elastic proportional range of the steels performance.

Geometry comes into play for sheer and tensile stress maximums. Maximum stress normally occurs in the outter layer/skin of the structure. Bending and shear-related failures initiate at points where the stress properties have been exceded, due to deflection or geometric concentrations.

Here's an article that discusses stiffness, flex modulus, relative to hardness, for knife makers: https://knifesteelnerds.com/2018/03/13/why-doesnt-heat-treating-affect-steel-flex/

This article talks about steel properties: https://engineeringdiscoveries.com/what-are-the-properties-of-steel/

This is an image from the article, which depicts stress/strain curves for a number of steel types. All 6 curves have a common start, their elastic proportional range. As long as the load, given the same geometry, is within that range, the steel will deflect and return to its original position.

Where each curve begins to deviate from that straight line, defines its yield point. All 6 curves are at different stress levels. That's where the steel affects the ability to return to its initial geometry. The purple line is about 23% of the strongest steel on the chart. As long as the deflection, represented as strain, is under the yield points, each has the same spring constant.

Yes, geometry will affect maximum stress in the design, and must be considered if one is changing a design. Geometry all affects Moment of Inertia, I. It has a n^4 power effect on torsional resistance as this part is designed: small changes in diameter can significantly affect apparent stiffness. Going from 9/16" to 3/4" diameter will nearly double the resistance. I don't have the calculations in front of me to quote exact numbers.

Steel type also drives cycle life and fatigue life of an article. So, yes, steel type is important. However, the spring rate doesn't change.

Bottom Line: you have the empirical test data which supports your targeted improvements, providing less tilt of the Spyder going through a corner.