Uncontrollable bumps// help me control the bumps

[MJA]

So. I recently bought a 2000 Ford Ranger 4x4 "Offroad". So far I am pretty happy with the vehicle, doing all the routine maintenance stuff I do when I buy a vehicle. Oil, Transmission Fluid, Shocks, Brakes, Transfer case fluid, Diff. Fluid, etc.

From the beginning, I noticed this truck kinda hops out of bumps. On washboard dirt road, it is actually a safety concern. Replacing the shocks had some effect, but not as much as I'd hoped. It's not so much like there's a steering issue as a suspension issue. The tie rods, ball joints, etc COULD use doing, but I don't think that's the cause of the problem. I've never owned a vehicle this light or with torsion bar front suspension. My truck does seem like it rides a little higher than other similar rangers I've seen around and I'm wondering if someone cranked the Torsion Bar adjustments down.

I'll defer to more expert advice: Do you think loosening the torsion system a little could help? I don't particularly care about clearing obstacles other than Michigan potholes but I do care about not... crashing and dying if I encounter washboard or even a couple potholes in a row. Also don't really care about ride comfort. I'd much rather just get where I'm going. I've never had a vehicle behave this poorly on washboard.

I'd like to think I'm a reasonably competent amateur mechanic, but I don't know much about the intricacies of steering and suspension other than swapping worn parts and doing half assed redneck alignments.

Thanks.

 

[rusty ol ranger]

Every light, stiffly sprung vehicle ive ever owned pitches like crazy on washboards.

If someone lowered the torsion bars it should of made them softer and actually made it more stable.

If someone raised them then yes it would make the pitching worse.

 

[pjtoledo]

adjusting a torsion bar does not affect the stiffness or softness of the ride. it is holding up the same weight where ever it is set, and will twist the same amount.
did you check the travel of the shocks? if the torsion bars were adjusted the shocks are no longer in the middle at ride height and will limit the amount of wheel travel.
an example is if the T bars are cranked to lift the truck the shocks are also extended. that severely limits the shocks ability to let the wheel drop into a hole, instead the entire front end drops, not just the wheel.
to check, mark the shock at ride height. then disconnect the top, fully collapse & mark. put top back on, disconnect the bottom, extend fully & mark.
I've had a 2000 4x4 since new, they are a bit jumpy on rough roads. bigger tires make it worse.

 

[Ranger850]

Too much tire pressure?

 

[adsm08]

adjusting a torsion bar does not affect the stiffness or softness of the ride. it is holding up the same weight where ever it is set, and will twist the same amount.

But when you adjust the bolts to make it sit higher or lower you are adjusting where the springs are in their tension range. If you have a torsion bar that has been tightened and is now 2 inches higher than stock it is much closer to it's max twist than one that is at factory ride height. It may actually drop better, because allowing the wheel to go down would be taking tension off of it.

Similarly a torsion bar that has been de-adjusted to drop the front will compress upward easier, but might not drop as hard, which will give squishy handling.

 

[8thTon]

Adjusting a torsion bar to raise the suspension is equivalent to adding a spacer under a coil spring, or a block under a leaf spring.. It does not change the spring rate. You're simply making the stop bolt longer. You could of course run out of travel at either end.

 

[adsm08]

Adjusting a torsion bar to raise the suspension is equivalent to adding a spacer under a coil spring, or a block under a leaf spring.. It does not change the spring rate. You're simply making the stop bolt longer. You could of course run out of travel at either end.

No. Adjusting a torsion bar to raise the suspension is the equivalent of putting these in a coil spring:

And let me assure you, THESE EFFECT RIDE QUALITY.

 

[8thTon]

No. Adjusting a torsion bar to raise the suspension is the equivalent of putting these in a coil spring:

And let me assure you, THESE EFFECT RIDE QUALITY.

I disagree - those things surely do change spring rate by preventing some of the coils from compressing, but turning the bolt on the torsion bar does not change the spring at all. Coil springs work by compressing linearly, and torsion bars work by rotation. Rotating the end of the torsion spring is the same as lifting the end of a coil. The equivalent of those things would be some sort of rigid tube clamped around part of the bar.

 

[adsm08]

I disagree - those things surely do change spring rate by preventing some of the coils from compressing, but turning the bolt on the torsion bar does not change the spring at all. Coil springs work by compressing linearly, and torsion bars work by rotation. Rotating the end of the torsion spring is the same as lifting the end of a coil. The equivalent of those things would be some sort of rigid tube clamped around part of the bar.

But the torsion bar can only twist so far. Just like any other spring when you push it to the ends of it's travel it gets harder to move. Adjusting those screws changes the ride height by changing the static twist on the bar. You tighten those bolts and you are essentially compressing the spring.

 

[sgtsandman]

I've seen more than one person on more than one forum say the same thing Adsm08 is saying. You crank the t-bar keys, and the ride will get harder.

 

[8thTon]

But the torsion bar can only twist so far. Just like any other spring when you push it to the ends of it's travel it gets harder to move. Adjusting those screws changes the ride height by changing the static twist on the bar. You tighten those bolts and you are essentially compressing the spring.

That is only true if the far end is not free to move. If you could measure the twist angle between one end and the other it will be no different, just as if you put a block under a leaf or coil spring the spring length isn't any different - unless it runs out of travel. You'd have to put a higher rate spring in it to make it stiffer.

It doesn't take any more force to hold the truck at a higher lever, it only takes energy to lift it.

 

[4x4junkie]

8thTon is correct. Turning the adjuster key is infact akin to putting a spacer (or washers as shims) underneath the lower coil spring perch. You're simply changing the position of the spring, the spring rate itself is not changed (if you turn the bar say, 4° via the adjustment bolt at the key end, the suspension control arm will also then be moved down that same amount (4°), giving you the lift you were after. IOW, the bar still has the same amount of torsional load (or compression, in the case of a coil spring) on it. Any change in ride quality is solely a function of the resulting change in the geometry of the suspension (the control arms being at a steeper downward angle / the resultant loss of suspension downtravel). This happens on TTB suspensions too, though tends to be less pronounced for a given lift height due to the much longer effective length of the TTB axle beams vs the IFS control arms.

As for the OP's concern, to me it sounds like one of: shocks, loose components (bushings, ball joints, wheel bearings, etc.), the torsion bars cranked up too high, too much tire pressure, or a combination of all of the above.
You didn't mention what shocks you put on (some cheapies are hardly better than worn-out OEM stuff), however I would suggest check tire pressure (should be set to what the sticker on the door states, not what the tire sidewall says), check over all the bushings in the suspension, along with the tie rod ends, ball joints, and wheel bearings. If everything checks out OK, next step would be to check whether the torsion bars have been cranked too high.
How I would check this is to note exactly where the wheel sits relative to the fender lip, then jack the truck up by the frame and note how much the wheel moves downward. Ideally this should be at least three inches.

 

[rusty ol ranger]

All i know is i cranked the bars on my expedition to clear 33s and it rode like total dog shit.

 

[pjtoledo]

I've seen more than one person on more than one forum say the same thing Adsm08 is saying. You crank the t-bar keys, and the ride will get harder.

because the shocks and control arms are out of sync with the travel needed.
a cranked T bar will have put the shock and control arms nearer one limit and farther from the other.
if you lift with the Tbar crank you are pushing the suspension towards its lower limits. drive over a hole now and the wheel cannot drop so the entire front end drops,,,and yeah, that makes the ride worse.

 

[sgtsandman]

because the shocks and control arms are out of sync with the travel needed.
a cranked T bar will have put the shock and control arms nearer one limit and farther from the other.
if you lift with the Tbar crank you are pushing the suspension towards its lower limits. drive over a hole now and the wheel cannot drop so the entire front end drops,,,and yeah, that makes the ride worse.

I've seen something like that with the CR-V I had. The 1.5" lift would bottom out the suspension from time to time because of it because no one had extension bolts with the right thread for the strut shafts to compensate for it. At only 1.5", it wasn't a huge problem but it made itself known.