question about Jackknifing your tractor trailer

by Ryyan
(London, Ontario, Canada)

Have you ever jackknifed your trailer or your tractor while the trailer was loaded? And if so, were you able to steer out of it or are you in it for the ride?


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May 17, 2009
Ryan and jacknifing.
by: Jimmy

Alright, Ryan. Welcome aboard, the fun begins on May 23rd. Ryan, you gotta promise you gonna be the best damn trucker in Ontario. Now, about jackknifing. Ain't no fun, pardner. I jacknifed my first year of trucking in wet weather, empty.

To explain how it is possible to jacknife, I would have to be a physics Professor, you know, such and such weight pushing this item on that angle etc. Sorry, I'm not a physics Professor, but I can tell you that the jacknife is caused by a rolling truck/trailer suddenly being slowed down and when the truck slows faster than the trailer, bamm, you got yourself a jacknife. The trailer is, in essence, pushing the truck, and since the trailer cannot go through or over the truck, it attempts to go around the truck.

In normal braking, the driver applies the brakes and is well aware of the trailer behind him, and is therefor careful not to apply the brakes too hard. Almost all jacknifes happen during a panic stop. As in heavy rush hour traffic, and driver is half asleep or following too close and suddenly has to brake.

The theory is, you must brake evenly on all 5 axles to stop and keep the trailer straight. There is a partial jacknife and a full jacknife. A partial is no damage, no collision between the truck and trailer. A full is when the trailer collides with the truck and the rear of the truck is damaged.

Sometimes on ice, you may start to jacknife just slightly and can get out of it. You need to de-clutch first to get freewheeling, then steer the opposite way the trailer is coming and say your prayers. Oh yeah, no braking either. It will happen so fast, that you will react without any thought. Hopefully you reacted correctly. Stay in touch. Jimmy

May 15, 2009
Answering Hervey
by: Anonymous

Hi Hervey, (from Ryan)

Yes sir, i'm currently registered to start my Tractor Trailor training this May 23rd. I'll be taking my course through the Ontario Truck Driving School here in London.

They gave me my books ahead of time and i've been reading, reading, reading since i've got them. Really, I think the Drive Test Centre here should give out these books to EVERY driver out there so they can understand and respect truck drivers out there on the road!! But thats my opinion!!

Well, hopefully i'll be out on the road soon but before that as i'm reading through the book and taking my course if I can't understand something i'll post a question here so everyone can learn, not just myself!! Thank you for taking the time to tell me your story! Take care, Ryan

May 15, 2009
Jacknifing the tractor trailer
by: Hervy


I got close to jacknifing three times so far. (Hopefully, I am done.)

All 3 times, I pulled out of it and recovered control. I was empty each time though which was worse than being loaded because it was harder to regain traction. Twice I was on ice and snow, once I was on freezing rain.


wait a minute silly me!

I DID jacknife a loaded tractor-trailer! In fact I total lost it. Well, I don't know, I didn't really lose it to a jacknife, I intentionally forced the jacknife by turning in to the guardrail to avoid hitting a lady sitting in the road like a stool pigeon in the rain.

Total loss my old freight liner. Didn't get hurt other than my pride and pocket(was owner operator). No tickets, no charges happened in West Virginia.

Things happen Ryan, you just try to learn from them and avoid them as time goes on.

You driving, or thinking about becoming a driver?


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