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Track bar and drag link angle

ksagis

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Trying to build up a better understanding of what angles people are running for track bar / drag links setups. And also wondering if anybody knows what the angle from horizontal is for a unlifted Bronco's track bar / drag link.

My rig has about 5.5" of suspension lift, dropped pitman arm, and track bar drop bracket - it ended up about 6 to 7 degrees of angle for the track bar and drag link.

Would love to hear what others have for lift, angles, etc, and hear how the vehicle drives at freeway speeds.
 

DirtDonk

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From the sound of it, yours does not sound too severe as is. As if the builder did other things to compensate.
Or used custom drops?
The typical drops available are for a 3-4 inch lift so are not enough for the typical 5-6 inch lift.

As for desired or original angle, good question! I don't think many have actually measured their stock ones, or bothered to put numbers on their lifted ones. Just that "lower is better" is typically adhered to just to get into the ballpark.

Got a picture of yours? Let's see how that 7 degrees looks.
I might be able to get an angle on mine later. I have 2.5" of lift and no drops just at the moment, for a comparison.
I'm lowering them when I can, but have not done so yet.

Paul
 
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ksagis

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Sure thing, here's a pic. There's a bit of parallax in the picture, looking at it live, the angles of the track bar and drag link looks very close.

I think knowing the baseline angle would be helpful for somebody that was building a custom front end so they could work to emulate it.

A picture of a stock front end is fine too, I can figure out the angle graphically

P.S. I know you likely hear it a lot Paul, the community appreciates your willingness to reply to all the posts. Getting to >40,000 post is quite a feat!
 

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DirtDonk

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Thank you, appreciate it!
The angle on the drag link looks great for that much lift.
Of course it being longer than stock and mounted over on the steering arm lowers the angle a little bit more than just the dropped Pitman Arm by itself.
So that’s a good thing.
And even though having the two bars equal in length is important too, it appears to not be quite as important as some of the other aspects in the real world.
We’ve had other members report that a slight steeper angle on the trackbar if it’s shorter does not seem to result in a lot of bump-steer.
Although I do think others in the past have reported a little, but we’d have to compile all the data to see who is having trouble, and what all has been done to the vehicle to know for sure and be able to compare.

And because yours is heavily modified and linked, it would have to be compared to someone with a similar set up.
I know you’ve been speaking about your rig in the recent past, but are you currently having driving issues when you’re out and about with the bronco?

Wait, what? Forty thousand? That must mean a lot of sleepless nights, and Jim just isn’t going to believe me anymore when I tell him I’m actually working from home!
Oh well… I can say this is just like workin’ right?😁😉😎
 
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ET

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Only pictures I have. I was told the draglink and trackbar should be parallel and same length. Of course that’s not always possible. Mines close parallel each other and only few inches difference in length. Drive fine but I don’t drive on highway. I don’t experience bumpstop but hard to tell with ram. I dont know link angles and never thought it matters. It could matter though. Bronco is at East Tx so I can’t put an angle gauge on it, sorry. 5.5ish inch lift.

Eugene
 

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ksagis

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Thanks ET, looks like you're about 8 degrees on your drag link, appreciate the picture.

Paul, the main issue I have is the rig is too darty for my tastes at freeway speeds so I'm trying to track down all the things that contribute, learn about them, compare to others, and then decide next steps. I've checked linkages and ball joints and all is tight there, which leaves things like track bar angles, toe, etc. Caster is in a great place at slightly over 7 degrees. Camber looks decent too.

After thinking about all this quite a bit, having a bigger angle on drag link and track bar would generally result in more bump steer, unless the drag link and track bar are exactly the same length and angle. If they're the same angle and length, the bump steer should be zero I think since they're going through the same arc. Getting into real world, and driving habits, makes this a lot more complicated.

I may be expecting too much for driving habits for a 50 year old design (although heavily modified), with 5-6" of suspension lift on a 92" wheelbase.

Right now, the first thing I'm planning to play with is my toe. With the ram on the tie rod and the way the linkage was built up, changing toe is a little more involved, and limited to discrete setting to keep the welded on ram flanges at right clock angle to axle.

Appreciate all the inputs, if anybody has a picture of steering on a unlifted bronco, or the angles, I've love to see it.
 

DirtDonk

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I think you’ve got one of the key aspects right there when you mentioned high center of gravity and short wheelbase.
Those are massively important.

But you’re also on track with the toe-in.
Dartiness can be a direct result of too much or too little toe-in for your particular setup.
And with most of our rigs, it doesn’t have to be by much. There’s a big difference in feel with just a 16th of an inch.
Unfortunately you’re kind of messed up it sounds like with trying to keep the RAM brackets the same. But then there is also the aspect of the ram itself.
What kind of hydraulic valve are you using, and are you still using a steering box or is it strictly ram?
Hopefully just ran assist?

Something you can do no matter what the other settings are though, is play with tire pressures. Larger tires are heavier and have an amazing amount of leverage against the steering. Especially so if your wheels are highly negative offset deeper) to the outside.

Have you had it on an alignment rack yet?
I know they can’t really adjust anything for you, but at least they can give you a full read-out so you have your baseline to work from.
 
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ksagis

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It's a Red Neck ram assist from West Texas Offroad, plumbed from a steering gear box, also provided by West Texas Offroad. From memory, think it's a 2" ram size but need to check.

Yup, it's been on an alignment rack with previous owner. Current alignment numbers below from the Big O Tires sheet:

Caster: 7.2 deg Left / 7.6 deg Right
Camber: 0.2 deg Left / 0.1 deg Right
Toe: -0.04 deg Left / -0.06 deg Right

Below are calculated values from numbers above and doing math:
Toe: -0.024 inch L / -0.036 inch R
Total Toe: -0.060 inch difference front to back, toe out

Toe out is defined at negative, so unless Big O reports things differently, I think I have toe out right now which seems to be an odd setup.

Given my suspension configuration and the ram, I need to turn the tie rod in full turns to keep the ram brackets at the right locations. One full turn of the tie rod then results in the two heims turning a full turn each. I can get a smaller setting by pulling the bolts from heims on knuckles, and turning each heim a half turn.

Base case, I should have two choices of configurations at 1/8 or 1/4 inch toe in. Suspect with my Krawler tire size of 35 inch x 13.5 inch, I might end up at the 1/4" position.

I think I'm going to start with the 180 degree turn of heims, which should take me from small toe out to slightly less than 1/8 inch toe in. If still darty, will go to 0.28 inch position. Not sure if the sweet spot is between those positions though.
 

m_m70

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The sweet spot for mine is just over a 1/4" toe in with 33x12.5" 15....Was very "darty" with less. Tire pressure had a lot to do with it as well. I run mine between 26 and 28lbs both front and rear and the wear pattern is good.
 

DirtDonk

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I ran toe-out for a few days, while doing a test of what setting my '68 liked the best. From approx. 1/4" toe-out to approx. 1/4" toe-in. Settled on 3/16" toe-in (if I remember) for now. Ended up having to raise my tire pressure in the front as well. Which I thought strange, but it worked for me in this case.
Apples to oranges here compared to yours though, because of my stock linkage with only 2.5" of lift and just 31" tires on narrow and tucked-in 7" wheels.
But you can do the same thing I did, just as you are discussing.

I would test your own toe measurements against the computer printout first though. Pick a measuring method and use your numbers to compare to before and after any adjustments.
And just do one rod end at a time too, I would think. We don't suffer from the same issue that most older passenger cars with independent front suspensions do with having to adjust both sides equally each time. It's still "a thing" but it's just not a major impediment so I have no trouble tweaking one side at a time on mine when I have that option. Which I did not in my most recent case.
And since that was literally the only way you could do it with stock linkage in the old days, Ford did not think it a big deal either.

So twist one Heim a half-turn and see what that nets you with your own measurements. From there you can either choose to test each time to be sure, or just estimate based on how much change was netted by one half turn of a rod end.
If one half turn gets you, for example a 1/16" toe change, you're in business without having to re-measure each and every time. Then when you find your happy place you can do a final measurement to see what the overall change was.

Speaking of which... I used a tape-on-the-tread method for my tests, but just realized I never compared them to the alignment numbers from the computer printout.
Dang! Now I've got to go back and review all the numbers again... :unsure: :eek::rolleyes:

Paul
 
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ksagis

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Paul, thats super interesting on the range of toe you ran and thanks for suggestion on only turning one heim. Silly me for not thinking of it.

If you remember, could you generally describe how the various toe settings drove and felt?
 

DirtDonk

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Sure. Generally speaking the toe-out felt reasonably good under most circumstances, but felt very nonlinear and over reactive when making sharp slow speed turns. Such as in parking lots.
In theory, this would be where the toe-out should work the best. But very possibly our short wheelbase and poor Ackerman angle works against this.

With the maximum toe-in it felt twitchy and not as in control.
At most of the settings in between those two was some degree or another of not happy.
Only at between 1/8 and 3/16 inch did it seem to settle down the best.
Which is approximately where all of my previous setups have liked it the most.
Here again though, all of mine have been modest size tires with narrow wheels. Not a lot of negative offset to put the tires outside of the turning center.
Not as much leverage against the steering system as something like yours.

Speaking of which, have we discussed what your wheel width and offset specifications are? And whether you’re running spacers or not?
Just more good stuff to know.
 
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ksagis

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Bit of additional info after doing more research, I had noticed my ram and tie rod weren't very parallel (based on pictures from PO they were parallel before the PO got an alignment and not parallel after the PO got an alignment). It looked wonky to me and dug around a bit. According to West Texas Offroad (vendor of the installed hardware), they should be parallel or twitchy driving at highway speeds may occur.

I need to address that first before playing with alignment.

Paul, I need to get the back spacing and wheel width, will reply on that.
 

ET

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It looks like the alignment folks adjusted by just rotating the tie rod to shorten or length instead of pulling the hemi and adjusting that. Or they did and didn’t put ram back to parallel. I’d mark each knuckle arms and measure the distance and rotate the tierod/ram tabs down. See how much change there is.

Eugene
 
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