Torsion Bar Cranking - Ranger-Forums - The Ultimate Ford Ranger Resource


Suspension Tech General discussion of suspension for the Ford Ranger.

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  #1  
Old 12-11-2008
D.
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Torsion Bar Cranking

Theres been a LOT of threads in regards to torsion bars lately. Crank them, uncrank them.. What I feel is lacking is a basic understanding of what happens to the suspension geometry when either is done.

Contrare to popular belief, Your front wheels do NOT travel in a perfectly vertical direction. They travel in an Arc..

When something effects one of the control arms, Laws of physics and trig show there is an effect on the upper arm. If one stays constant, the other must as well. For every action to one, there is an equal reaction to the other.

When the lower arm is forced downward, the upper will move downward as well. The opposite also happens, when the lower is forced upwards, the upper moves in the same direction as well. The Upper arm has a constant value. Its not going to shorten nor lengthen, thus when the torsion bars are cranked, the top of the tire will move outward. When the tension is let off the torsion bar, the top of the tire will move inward. The Axis of the upper arm is a constant. Eccentric's or ' Cams ' can be used on the upper arms to move the pivoting points but after being ' aligned ' or ' adjusted ', they become constant once more.

So long as both arms are the same weight, with the exact same balljoint location, the wheel WOULD travel vertically. Such is not the case with Ranger Trucks on Torsion bars. The Upper Balljoints sit a full inch and a half inside the vertical position of the lower arms. The offset is provided by the deflection angle of the spindles themselves for tire clearance.

If you look at the top of the spindle in this pic..
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.. Its clearly seen how the spindle joggs inward in its design.

The lower control arms are MUCH longer from their pivoting point then the uppers ( roughly 5.25 inches SAE ).

If the arms were completely Parallel to one another on a horizontal plane, they COULD have a straight vertical travel. Unfortunatly, this isn;t how they were built.

Theres many angles to the front suspension. If ONE is effected, they all are..

Even though this picture depicts body roll, it also shows the suspension as to where its ' moving parts ' are located/effected.

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Lets apply math here.. in this picture..
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The torsion bars are used to change the vector angle of the lower control arm. This will change the geometry/angle of point ' c' . ' Lifting ' the front end makes angle ' c ' smaller, lowering makes it bigger. BOTH have an effect/impact on the surface area of your tire, its contact patch, and can cause unever wear OR pre-mature failures of other suspension components.

Torsion bars have a rating that is calculated into the geometry of the suspensions design. Weight of the vehicle and tire size have a mathematical value. Tire rubbing, turning radius and other factors are also tossed in to the equation.

ANY changes made to the torsion bar be it tightening, loosening or changing bars themselves should be followed by an alignment to put the geometry back into proper functioning fashion.

Hope this helps.
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  #2  
Old 12-11-2008
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Great post!
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Old 12-11-2008
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Thanks D. This helps a lot for us suspension noobs.
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Old 03-15-2009
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awesome this clears up quite a bit!
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  #5  
Old 03-31-2009
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Thanks for the explaination. I have absolutely NO knowledge or experience with torsion bars, but this at least gave me a clue as to what I am working with. Great Post!
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Old 03-31-2009
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Thats cool, but i've checked my alignment on two separate machines and they were in spec. with the tbar cranking. not saying the upper ball joints wont wear faster or anything. but the specs were there
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Old 04-01-2009
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After I cranked my T-bars the camber on both sides were right in the middle of the specs. The toe was off a little. I suspect the camber was off before I cranked it.

I only cranked it 1.5" and the ride height was still within the Ford specs for a new suspension. It was right at the max but not over. Ford also has specs for used suspension and it was above that range.

After 40k miles of so I checked the ride height again and it had sagged a little. I cranked it a little more to keep it at the maximum new ride height. At over 95,000 miles now, the front suspension is showing no signs of problems. I am due for a check on the ride height but will wait until I am also ready for a front end alignment. Except for a shock replacement, I don't think any changes should be made to the front suspension without an alignment check.
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Old 04-01-2009
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Ball joints will wear out quick and you will have uneven tire wear as well.
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  #9  
Old 04-01-2009
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Quote:
Originally Posted by Prerunner-Ranger View Post
Ball joints will wear out quick and you will have uneven tire wear as well.
What do you call quick? 95K miles seems like a lot to me and the ball joints don't indicate any problems. My original tires (BFG AT) lasted over 65K miles and had even wear. The current tires (Michelin LTX M/S) are wearing very little and show no signs of uneven wear. I expect them to last over 80k miles.
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  #10  
Old 04-07-2009
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I got 10k out of a set of ltx's.

Nice post.
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  #11  
Old 04-07-2009
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What happened to D.?
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  #12  
Old 04-07-2009
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Quote:
Originally Posted by Dumpedmk3 View Post
I got 10k out of a set of ltx's.

Nice post.
I am approaching 30K with my LTX M/S tires and they show very little wear.
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  #13  
Old 04-12-2009
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at my work all we use on our e250 vans and f350 2wd 1tons is the ltx's. we drive about 2-300 miles a day and the most we got out of a set was 115k miles. not offroad vehicles or nothing but it still says alot... and which are the actual torsion bars. before i get my lift installed i wanna crank them myself bc the shop wants 50 bux just to crank em...
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Old 05-02-2009
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Quote:
What happened to D.?
he got a week long ban , and then told rf to go to hell,

to bad because i always looked for his posts , his truck is original to say the least and he was really good with the tech aspect of things.
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  #15  
Old 09-04-2009
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Quote:
Originally Posted by Prerunner-Ranger View Post
Ball joints will wear out quick and you will have uneven tire wear as well.
i have to agree. i cranked mine and couldn't get a good alignment to save my life. after a set of tires and ball joints all the way around, i had to put them back to norm.

good post though
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  #16  
Old 09-04-2009
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posted before i looked

Last edited by Hanks Rangers; 09-30-2009 at 11:10 PM. Reason: mental malfunction
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  #17  
Old 09-28-2009
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This sticky has wrong info in it, if you crank your torsion bars it will pull the top of the wheels in, not push them out. So instead of it adding positive camber, it is subtracting it or adding negative camber. Either way, if you crank them enough, just get an alignment after if your camber is ****ty...
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  #18  
Old 09-28-2009
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Quote:
Originally Posted by korey89 View Post
This sticky has wrong info in it, if you crank your torsion bars it will pull the top of the wheels in, not push them out. So instead of it adding positive camber, it is subtracting it or adding negative camber. Either way, if you crank them enough, just get an alignment after if your camber is ****ty...
Sry sir but you are wrong.
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Old 09-28-2009
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Prove me wrong please
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Old 09-28-2009
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Quote:
Originally Posted by korey89 View Post
Prove me wrong please
I can think of multiple people, inlcuding myself, who have never had issues with camber and have cranked tbars. My tires wear fine also.
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  #21  
Old 09-28-2009
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lol leave it to Aaron to miss the whole point. Im just saying that d was wrong saying when you crank it adds positive camber, it adds negative.
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  #22  
Old 09-28-2009
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Quote:
Originally Posted by korey89 View Post
lol leave it to Aaron to miss the whole point. Im just saying that d was wrong saying when you crank it adds positive camber, it adds negative.
x2. adds negative
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  #23  
Old 09-28-2009
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Quote:
Originally Posted by korey89 View Post
Prove me wrong please
I'm not exactly sure how to explain it without pictures so how about you prove me wrong.
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  #24  
Old 09-28-2009
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Because I don't care enough to prove someone wrong who doesn't even have a ranger?
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  #25  
Old 09-28-2009
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Haha dang you are a cleaver one.
Not like a have to worry about that stuff anywase with my solid axle 3 link.
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