Question:
ive only been driving a trailer for about 6 months and not very much in the rain - last week i had to stop pretty hard for a yellow light and when i came to a stop i looked at my mirrors and the (edited) end of the trailer was ALMOST in the other lane and it appeared that it wanted to kick out. just wonderin from a relativelly newbie.

Answer:
Yes that will happen more so when your empty and in the rain or on any slick road. Since the trailer brakes apply before the tractor they will lock up quickly if the trailer does not have good traction. The trailer can lock up on dry pavement also if the brakes are applied to hard. The lighter the trailer such as flatbeds the more they will do it. Trailer brakes will seldom if ever lock up when you are fully loaded.
This is one of the reasons it is very important to drive slowly and very cautiously especially when the road conditions are poor. To avoid this happening keep a good following distance, drive slowly and pump your brakes when you come to a stop. Under normal circumstances you only ned to apply enough brake pressure to stop you and then let off so the brakes do not lock up. You are applying a manual anti-lock of sorts. On occasion I have had to apply stab braking. That is when you hit them hard and let off. You do it continuously until your stopped. This method allows you to apply alot of brake pressure quickly and by letting off again quickly it will keep them from locking up.
Basically the only way to keep the trailer from locking up and changing lanes is to let off the brake. Since you still have to stop you simply reapply them. Off-on-off-on until you have stopped. Hard and fast in an emergency stop and slow and easy in a regular stop.
Hope that helps.

Answer:
that helps a bunch, they taught me stab braking in trucking school but ive never done it. thanks a bunch

Answer:
Hmmm...interesting.Maybe one of the professionals
can explain what a jacknife actually is.
As compared to a trailer skid caused by traveling too fast for
conditions.
Answer:
I was always under the impression that a jackknife was when the drive tires slid out, causing the tractor to do a 180 degree turn, and hitting the trailer. But I suppose if the trailer wheels locked up, and the trailer came completely around, that would be a jackknife too.

Answer:
i'm reaching back a bit here but...
a jackknife is the result of a physics rule called "the right hand rule" associated with rotation. normal forward rotation of tires produces a force vector in the left direction.
you've maybe seen this force before by holding a bike tire in your hands and spinning it. if you try to tilt it's axis it will resist or if you are sitting on a swivel stool... tilting the spinning tire will make your stool rotate.
sudden stopping of the rotation will remove the forward motion of the wheel temporarily leaving only the left directional force.
if the rear tires of the trailer come to a sudden stop it can make the trailer swing to the right. if the rear tires of the tractor come to a sudden stop it will result in the tractor going into a right hand spin which in turn will result in the trailer swinging to the left.
hope that's at least more clear than mud.
i can go into more detail if anyone wants

Answer:
That would be good if that was the question.
An easier way to say it is the sliding wheels always want to take the lead.

Answer:

you just like eggin' me on
sure it would be easier... but it doesn't really say the same thing now does it?

Answer:
Yes it does. It's the same thing only different.

Answer:
ok so "sliding wheels want to take the lead" - so is that what happened with my sudden stop in the rain, the trailer tires locked up and wanted to take the lead? so to prevent this as said above is to pump 'em - correct?

Answer:
You said in your post you stopped hard. Correct me if I'm wrong, but I'm assuming you spiked the brakes with either an empty or lightly loaded wagon.
Under those conditions almost all trailers will slide, usually towards the curb due to the slope of the pavement.
I'm also assuming your ABS was functioning properly, otherwise the trailer would have gone a lot farther than "almost" into the other lane.
Best way to avoid a repeat is not to put yourself into a position where rapid application of the brakes is required.
BTW a "jacknife" is when the tractor and trailer fold into each other just like the implement it was named after. It will occur when the two get at a certain degree of angle to one another-sorry-can't remember the exact degree and too lazy to dig it up.
In your career you'll hear a lot of BBR's blow off about how they pulled out of one. Ain't gonna happen Maynard. Once you get bent to that point the laws of physics takes over and no amount of luck or skill will stop the outcome.

Answer:
yep it was an empty trailer. i was in a 40 mph zone and was probably going 35 and had to stop within 50 feet, i just applied even brake pressure and did not pump or let up on them. what is BBR?

Answer:
Thats correct if they start to lock up. Avoiding sudden stops in bad weather is the best way to prevent this. If you have to stop quickly then stab braking or pumping is the way to do it.
Actually there is a point of no return. Until then you can get it straight. But that point can come very quickly.
Here is what will happen in certain cituations.
Steer tires lock up = plow straight ahead.
Trailer tires lock up = trailer will swing and change lanes or better said attempt to take the lead. Can cause a jack knife..
Drives lock up = drives swing right causing the tractor to spin out into the trailer and you have a "jack knife".
The number one cure for a "jack knife" is to have properly adjusted brakes all the way around.
In your cituation it sounds like the trailer brakes locked and the only way to get out of it is to either let off them all together or pump them.
BBR is slang for BillyBigRigger, Super Trucker, etc.

Answer:
found this for visual learners like me


Answer:
That is the long drawn out version.
Shorter version,
http://www.jjkeller.com/ideaoftheweek/idea1190.htm?action_code=89653
and Thank you.