Jackknifing
 

Hi, I'm sure alll you experinced drivers have a interesting story to tell concerning this topic...I hope you can mention for beginners your methods used to prevent and control jackknifing.

Thanks

Just like a car, go easy on the gas, easy on the brakes, leave alot of following distance and watch your speed. In other words, keep your tires from spinning and keep them from locking up. Its alot easier to prevent a jacknife then save one. If you do jacknife then good luck! In most cases its because of over braking, but the brakes would have been applied for a reason so you probably need them, so letting off is a different problem, oh boy, see what I mean? A jacknife can be saved but you need alot of room which you usually wont have. Its usually going to take letting off the brakes and clutching so all wheels can rotate freely, and in some cases a little throttle, of course you steer into it, but when that trailer corrects its going to have a big head of steam going the other way! Saving it may not be humanly possible so its best to learn to avoid it.


If that doesnt work, take a couple bungee cords and hook one end to the side of the trailer and the other to the side of the tractor and repeat for the other side. :wink:

A jackknife can be saved but like Snowman said, you want to make sure you never have to find out if you have the ability to save it or not. I have seen one that was saved, only because the driver knew it was gonna happen before it actually started happening. He felt it starting to go and was already getting himself ahead of the trailer. Sometimes you can outrun the trailer(in an ungoverned truck of course) and pull it back straight behind you but you need the room to get on the hammer and stay on it till it comes back behind you. The worst you can do is to hit the brakes, unless you want to get the trailer jackknifed around to you faster. Best bet, drive like Snowman said so as to not have to jam on the brakes or be mashing the throttle. If you have hit black ice and that causes you to start the jackknife, your pretty much toast right off the bat if you don't feel it right away and get off the throttle and into neutral so your wheels are free wheeling.

Had it happen to me pulling a set of wiggle wagons down a steep grade. Was just moseying on along stab-breaking my way down when lo and behold I see that rear kite looming sideways in my westcoast mirror. Holy $#$! What did I do? About the only thing I could...stepped on the gas going downhill!!! Slowly but surely, the set straightens out but now I've got another problem on my hands because at the bottom of the hill is a busy intersection with a light. Can't jam on the brakes and I can't slow down! Luckily, heaven smiled down upon me and I caught a green light with no cars backed up. Laid on my airhorn and just sailed right on through!!!

That sure was a close call! I always avoid that hill now and take an alternate route if I've got a set or a pup on my back. Found out later that 20 years ago, a guy lost his breaks flying down that hill with +90K gross in the box and 2 logbooks under his seat. Killed about 5 people and ended up doing a long stretch in the can.

The city tried to ban big rigs from that hill but they got sued by some trucking companies because it was a state route.

I have no first hand experience of this, but I have heard that braking of trailer only may help get it back behind you. :shock:

Is this acceptable practice, should the occasion arise?

Creek

Maybe! Ha ha! Anything that works is acceptable. The reality is that its a feel thing. And the odds are against you. Trailer brakes handles are slow to react and when they do they tend to grab hard. They're also becoming obsolete in later models. Used perfectly for the situation it could be just the ticket but without alot of practice it would probably make things worse. Any jacknife caused by overbraking means you probably have no where to go so its a lose lose situation. If it was caused by your drives spinning then you have a chance if you detect it in time, just let off the gas.

In the old days, this was called "getting her straightened out"....but these days the 'modern' experts say No don't do it- it's also the #1 reason besides cost- that companies don't equip their tractors with them. I've been sucessful several times using this method. But you have to be understand....once the trailer is 15% out of line- you're not going to get it back. And if you use it- improperly you can actually CAUSE a jackknife with it. It should only be used on level-straight pavement or a gentle decline. If used on sloped/curved/banked it usually makes the problem worse.
When you do use it--you have to use the pedal too and smoothly try to pull ahead of it.....this means you'll need open pavement ahead. This is where the rub comes.....(1) you're probably in the jackknife because you're trying to STOP, (2) by the time you start to "feel" it coming around.....it's probably already too late.
(3) you're probably not on straight pavement without traffic spun out ahead.

Oh, P.S. You don't need a "ungoverned" truck to outrun your trailer in a jackknife. If you're driving 65 or 68(full speed-bumping the governor) in ICY winter weather.....you're not going have time to even see your life flash before your eyes...much less time to "try" to save a jackknifing rig..you're just fixing to have a hell of wild ride- and if lucky you'll wake up in the hospital.

And this thread is in the wrong forum.

The closest I've came to having my trailer pass me up was last winter.

I was heading across US 30 in PA between Latrobe & State College. The roads were bad and I was praying to see a place to pull over and sit it out. Well, that didn't happen...

I started down one of the mountains when the traffic ahead of me was at a dead stop. I was only going 10-15mph at the time. When I hit the brakes, that's when the trailer decided to break loose. I got off the brakes, trailer straightened, back on the brakes, broke loose again. I was coming up on the stopped cars pretty quick with my only outs being a deep ditch on the left, hit the cars in front of me or try the strength of the guardrail. I grabbed the trailer brake lever and worked it without touching the pedals on the tractor. Somehow I managed to get it stopped - with about 1 foot of clearance in front of me and the trailer directly behind me.

When I got to the bottom of the mountain I pulled off the side of the road and just "shook" for about 30 minutes.

One good thing (I guess) - the cars behind me stopped tailgating after that.

I do have first hand experience with a "Jackknife", fortunatly the jackknife lost.

I was east bound on 1-94 just outside of and approaching Chicago, it was very early morning around 0100-0200 or so. Loaded with about 22000lbs in the trailer. It was a warm spring night on straight and level ground, however it was raining. Traffic was very light with only a few 4wheelers near me. The rain was "pooling" on the road. I was at about 50mph. Any 4wheelers that were near me had cleared me and I was basically alone. I was in the center lane of 3.
I felt a pull in the seat of my pants and looked out the mirror and saw the trailer on its way around past the 15 degree point. You really have no time to thing about whats happening and you mostly just react to the situation. I did not steer into the trailer but opposite it, it was swinging right and I steered left until the pull I was feeling went away, this kept the tractor and trailer inline, however, it created a new problem. I was going down the road inline, but sideways. The initial correction was naturally overcorrected and the trailer begun swinging to the left, again I could feel this in the seat of my pants. I countersteered back to the right, again keeping the tractor and trailer inline, but still going down the highway sideways. The ossilations continued but dampining with each correction. I am guessing 4-5 swings and corrections and it was over. When the dust settled I was in the hammer lane, didnt hit anything or damage anything. (With the exemption of my shorts). I did not use any braking during the swings. (Service or Trolley).
If any of the 4wheels had been along side me during the swings, they would have beeen "swatted" off the highway.
To this day the real cause is still speculation, however, I strongly believe the trailer tires hydroplaned on the "pooling" water. The tractor never lost traction.
When the tires hydroplane they are still spinning but all contact with the road service is lost. No traction. Pulling the trolley brake would have "locked" the trailer wheels, probably making the trailer uncontrollable.
Since that day I have had a much greater respect toward a combination vehicle and how susptable it is to upset.

I cant say this technique would work in every situation, I got very fortunate that the outcome was favorable, and an amazing learning expierence.

Regarding a governed truck. If you are on surface conditions that could induce loss of traction, stay well below the governer so you have some power available that may allow you to accelerate out of a Jackknife.

Kinda makes you believe in Guardian Angels don't it. You were very very lucky....