Traction Bar Options

[Torkman66]

@gnsteam did you use the bolt-on piece that attaches to 3rd member bolts or weld that end?

 

[Torkman66]

Received the Traction Bars from @catfan today. Very nice! Heavy duty and well made. He included all grade 8 mounting bolts. Had a minor issue with one of the bars and Catfan called and took care of it. Really great guy! Highly recommend his TBs. Less than $200 shipped...received them 4 days after ordering.

The main differance between the TBs Duffs has and these from Catfan is how the TB mounts to the front bracket. Duff's is a "spear" mount and Catfan's is a Heim Joint. I believe the Heim joint is better in that it allows for easier rotation of the TB during suspension travel. Catfan's rotate at both ends of the TB while Duff's only rotate at the u-bolt bracket.

I've learned a lot about TBs over the past week. I now believe that the bolt on TBs like Duffs and Catfan sale are great for street and mild off-road (going fishing) applications. I figure that is the majority of Broncos today. If you have a standard, unchanged leaf set, probably do not need a TB. However, if you have removed any leaves to lower the rear end, or have installed a big HP motor, highly suggest these simple bolt on TBs. They do not change the ride stiffness hardly at all. Not sure I can even notice any difference.

The only other thing I would strongly suggest, no matter what your intended use, is the WH extreme u-bolts and leaf plate. Cheap investment for a MUCH stronger system. The 5/8" u-bolts on their extreme system gets torqued to 125 ft pds. That is probably in itself enough to eliminate most axle wrap on street driven Broncos with untouched leaf springs, but if you also add the TBs, your golden. Simple request to Catfan and he will make the holes enlarged to 5/8" to fit the WH extreme 5/8" u-bolt size.

Here are some pics of the installed TBs from @catfan:

 

[dmoses42]

Might just be the angle of the pic, but that leaf spring eye bolt looks loose. Hopefully it's still in mock-up?

 

[Torkman66]

Dang, what an eye! I took the pic after loosening everything up to ensure no binding or preload then retightened. Amazing attention to detail!!

 

[gnsteam]

@gnsteam did you use the bolt-on piece that attaches to 3rd member bolts or weld that end?

I used the bolt on bracket. The Catfan TB looks like a great option.

 

[Hallboss]

Damn... I wish I would have seen this prior to last week. I just installed these Hellwig traction control springs https://www.hellwigproducts.com/products/?partnumber=2002 $96 on Amazon. Huge difference with my lift blocks and wedges that caused major wrap. Same conclusion as above, the torque is more planted and I don't think I will be smoking u-joints anymore. Very simple install. Probably would have and still might do the Catfan version, seems more legit then the added Hellwig spring. I'll run with what I have now to see what happens.

 

[Hallboss]

Pic of the Hellwig’s

 

[Torkman66]

@Hallboss one thing nice about those is that the axle can still move in a rearward arc. Would like to know if they changed ride at all.

 

[Hallboss]

@Hallboss one thing nice about those is that the axle can still move in a rearward arc. Would like to know if they changed ride at all.

I haven’t noticed any difference. Still rides like a truck!! Lol. Have about 6 hours of driving since the install. No more popping noise and the “WTF was that noise” outbursts. I have the Deaver 1645H9 leafs and Duffs midnight MS2020 shocks. Lower tire pressure and it isn’t that bad. No noticable difference from before. Actually think it feels more planted while driving and definitely under heavy acceleration.

 

[Torkman66]

That setup directly deals with the front section of the leaf springs where the “s” bend happens during axle wrap. They will likely work very well. Easy install, bolt on, and removable without leaving any trace.

 

[Scoop]

Looks like a nice setup. That should handle all your hp!

 

[ntsqd]

Something that doesn't seem to be appreciated is that the pinion angle of a leaf-sprung suspension does change as the suspension cycles. It doesn't change much, but it does change. With a 9" this is semi-easy to see. Unhook any traction aids that might be present and scab together a straight bar about 2 feet long that can be bolted to the pinion carrier. Cycle the suspension. Can measure the angles if you want, but they're enough of a change that most can see it. If the traction aid is a ladder bar, then bolt it back on and cycle again. Now what is the pinion angle doing? IF it's not exactly the same as it was "unaided' then the difference is the source of the stress in the ladder bar.

The reason that the ladder bar type traction aids have so much stress in them is because they force the leaf spring into an 'S' shape. This is because they require a far larger pinion angle change than what occurs naturally. They are a radius arm as they have only one pivot point. The shackled versions don't help this, they still really only have one pivot point. It just happens that the shackle allows that pivot to translate fore and aft a little. All that the shackle does is accommodate the small change in spring length that happens as the spring flattens or arches during the cycling of the spring. When the ladder bar is eventually built strong enough then the next failure mode is very likely to be the buckling of the main leaves.

The Wrap-Trap and similar two pivot traction aids aren't any kinder to the spring's main leaves. With a rigid connection at both ends they can't allow the spring main leaf to grow or shrink in length without also causing the pinion angle to change. Part of the reason for the poly bushings in the Wrap-Trap is to give it some fore/aft compliance so that it has less influence on the pinion angle. Some Oval Racing rear axle linkages employ some very stiff springs on a similar axle link. The rest of the suspension is entirely different, I only point out those springs to give some something to ponder.

It is all of this observation and experimentation over the last 25-odd years that has lead me to conclude that if a Wrap-Trap type traction aid isn't enough then you need to go to a 3 or 4 link for the rear axle. Keeping the leaf springs at that point is still possible, but it's a whole new level of complexity to do so.

 

[Broncobowsher]

Before I put my shackled arm on, I had just soft springs. I parked it on a steep grade. The springs were flexed into the S-shape. Pinion pointed really high. Nearly to the point of binding the U-joint. You can't tell me that controlling the axle wrap with a single arm is more harmful than running just a spring. Maybe if it was an axle that never had any torque applied to it (unbraked trailer axle?).

Yes, there are stresses on the torque arm. That is what it is there for. If the arm wasn't being stressed, it would be decoration. Being stressed means it is doing something. What that something is, well it is evening out the stresses in the leaf spring. The front isn't being over-flexed into an S-shape while the rear having the leaves spread open. That is a good thing for a spring pack. The front is controlled from going into a reverse arc while the rear isn't being forced into a tight radius just from acceleration.

To claim that a leaf spring must go through it's natural arc with no exception. You have never put a GoPro under a (stock) truck and gone for a drive to see what really happens. The pinion angle is all over the place. Add a torque arm, the pinion is actually much closer to it's natural path than running without one. adding throttle or braking doesn't send the pinion into wild angles that you get without one. That theoretical perfect theory is a load of crap.

 

[ntsqd]

I haven't done the GoPro, but I have seen many who have and then posted the results. In no way do they contradict what I have seen in person and seen reported. They confirm it. With a soft leaf spring something is needed. I firmly believe that the ladder bar over-exercises the springs. More than does the Wrap-Trap and similar designs. I attribute this to the fact that cycling the suspension with a Wrap-Trap is very close to being a parallelogram rather than a simple swing-arm.

My point is that the ladder bar is the most destructive to the leaf springs, not that any of the solutions are good. Some are just better than others. Oddly, the two most "Religious" camps are those with a Wrap-Trap and those with a ladder bar. However, the ladder bar camp tends to feel the most persecuted.

 

[FramedCoyotes]

I worked with Duffs for 16yrs, you can't go wrong with there Torque Tamer or Classic Traction Bars!
https://dufftuff.com/product/torque...bar-1966-77-bronco-configuration/#choose-year
https://dufftuff.com/product/classic-traction-bar-1966-79-bronco-1967-79-f-series/

 

[Torkman66]

Check out this youtube link. Best example starts at about 1 minute in to about 1:15. Easy to see that the front of the leafs are bending under load. Pinon is headed north as axle rotates CW. Also easy to see that having something that limits the axle from rotation CW (up) will help reduce axle wrap. This with a 10 or 11 leaf stack.

After watching about 30 axle wrap videos and reading several axle geometry articles, I have learned that in most street applications, the rear shackle moves about 2" aft to absorb the increased length of the leafs when compressed to about flat. On my bronco with a 2.5" lift, that is about a 4" compression from sitting arched to flat. When a fixed length TB is introduced, connected at the u-blts and up to the front leaf eye, that front portion of the leafs cannot easily compress. The TB and the leafs move up and down in parallel but most of the compression of the front leafs is restricted due to the fixed and rigid length of the TB. This is what makes the ride harder...half of the leaf (the front half) is not able to compress as normal. The rear leaves still compress as normal whuich results in the rear shackle still moving but only about 50% of normal...so about 1". Fixed traction bars do a good job of minimizing axle wrap and do a great job of firming up the entire rear axle geometry, but the tradeoff is a loss of ride to some degree. For most pure street rides, not noticiable. However, not great when truck suspension is used for a lot of non-flat terrain.

So what I take from this thread (great inputs all), is that axle wrap is a real thing that increases in concern as your tires get bigger, HP increases, and/or leaf stack is weak or soft. Additionally, axle wrap is application specific. If you have an around town driver, likely will never have any issue under almost all conditions unless you have weak springs. If your hitting the pedal hard, burning out the tires, have lots of HP, even in town you will risk damage due to axle wrap. If rock crawling, its all a whole new issue that requires much more thought, prep, and $s. If my bronco was to be used in an off road environment very often, I would absolutely look for a TB that has a built in shackle or pivot that allows the TB to move aft during suspension but remain rigid during axle torque.

 

[ntsqd]

Were there more room to employ a leaf spring of special design then I'd suggest that the design used under an old Desert Race truck be employed. The front side of the spring packs were built rather stiff by National Spring. Lots of leaves and not a lot of difference in length. The rear part of the springs were almost 1/2 again longer than the front part. There the leaves had a much larger length difference between each adjacent pair. The result was essentially a trailing arm front combined with a 1/4 elliptic rear. The rules of the class that it was built for at the time didn't allow anything like a ladder bar or a Wrap-Trap, so the springs had to do it all.
Unfortunately, the real estate to do that under an EB DNE.

 

[Torkman66]

@ntsqd That is really interesting. Basically, what you are describing (kind of) is the engineering that @Hallboss used in his post above. Makes the leafs in front of the axle stronger so that they minimize bending during torque. I actually think that the Hellwig TBs that @Hallboss has might work best in that they will help strengthen the front leaves where the wrap begins but also react better during suspension travel allowing the leaf stack to lengthen normally and the rear shackle to swing the full 2".

 

[ntsqd]

That was, by today's stds., an old truck. The general idea not new by any means.

I would be very careful in using anything that clamps onto a leaf spring. Not something that I would do except as a trail fix of some sort.

Ever noticed the traction aid used by Toyota under the rear of their 80's era 4x4 trucks? It is hiding in plain sight. Look one up and notice the rear keeper on the under-riding Over-Load leaf. In not very much spring wind-up that keeper is going to come down onto the top of the main leaf. Turns the OAL into a traction aid and controls the spring wind-up.

 

[Torkman66]

Looking at various reviews of that Hellwig setup suggests folks are very happy with it. Some say it eliminated axle wrap and tire hop. For town driving, seems like a good solution.