An Unexpected Slide

full

Unexpected events are what separate the men from the boys. This isn’t based on a real event, it IS the real thing. So I’ll tell a little tale:

I was in Lexington, Ne waiting for my trailer at IBP. It was an ugly week, bunch of loads going places I wasn’t. So Kirby, my dispatcher, offered me a long delivery Amarillo that loaded that day. I jumped on it thinking I’d run through Elk City, Ok, where I’d spend some time with a friend and my brother. Wasn’t real thrilled about time off away from home, but it was by far the best option.

So I’m watching the weather as I cool my heels knowing that IBP just might screw this up. (deadline ship was 2 days away!) There’s a winter storm bearing down on Kansas, freezing rain that night with a day of blizzard conditions following that. I was rather used up, and saw them grab my trailer about 18:00, so I sacked out.

Sometime shortly after midnight, I get the CB call that I’m ready to go. Needless to say, I got my rear in gear and was southbound within the half hour. And shortly after finding Kansas, I found the ice. It was pasable, but slow. I found Oklahoma, and wet roads, around daybreak, and very soon the freezing rain had become a light drizzle. So far, so good.

Now it’s an hour and half later, and I’m making tracks, cruise set about 68, there having been no signs of ice on the grass and trees for over an hour.

(yeah, yeah. I’m being long winded cause I’m bored, so just keep reading! )

Now somewhere south of Woodward there’s a set of 45 degree S-curves that are nicely banked and large radius, so there’s no need to slow down. (been through em on a bike at more than the ton.) I roll through the right and I’ve just stabilized the left when:

“BUTT TO BRAIN! BUTT TO BRAIN! WHAT THE *#$& !”

Now if you’ve been at this a while, you know what I’m talking about. The seat of my pants had just informed me of a unexpected and undesirable yaw event. (the rotation axis of my rig had just shifted well forward)

A quick glance left showed no sign of the trailer. Expected, but unpleasant nonetheless. A right glance showed, yes, you guessed it, trailer. LOTS of trailer. And now for our quiz.

One of these is the right choice, the others will have various unpleasant outcomes. So, do you:

A) lightly apply the brake pedal to slow the truck.

B) use the Johnny bar (trailer brakes) to pull the trailer back in line.

C) disengage cruise to allow truck to slow down

D) disengage cruise, maintain neutral throttle (an in-gear coast)

E) accelerate to pull the trailer back in line.

Hhmmmmmmm…………..

‘A’ and ‘B’ would have similar outcomes. Your trailer tires are already sliding, teetering on the edge of adhesion. Any brake application will almost surely lock them up, reducing their friction (a rolling tire has more traction than a sliding tire, even if it’s rolling with a high slip angle.) and, combined with the slowing tractor, send the trailer swinging to the right. Well, swinging until it ends up in the ditch or smacks your cab in a slow jackknife, anyway.

‘C’ is an iffy choice. As the tractor slows, it’s pushing back against the kingpin. Which would be fine if your trailer was inline. But it’s not, and as you push back, the momentum of the trailer pushes the back-end of the truck forward at the same time it’s also yawing it to the side. Not a good idea! You might get lucky and have enough traction at the tractor to keep it from snapping into a jackknife. But you might not! Do you feel lucky?

‘E’. Well, you know how when you come up on a wreck and the truck and trailer are on their right side, across the road, with the top of the rig facing his former direction of travel. And you wonder, “how’d he do that?” This is how you do that! Nuff said?

Which leaves us with ‘D’. The idea being to minimize the traction you’re requesting from your tires. Some people prefer the ‘push the clutch in and coast’ method, which is basically equivalent to this. Just be careful reengaging that you match RPM or else you might cause another skid, with the tractor this time. I’ve always had a good feel with the throttle and prefer that way. There’s still no guarantee that you won’t further lose control with this technique, but it gives you the best chance of a safe recovery.

And that’s what I did, I kept just enough throttle to keep just the slightest forward pull on the kingpin. Some speed bled off, the trailer slowly came back in line, and away I went! By the way, that is the most stable dynamic state you can have a truck in. It’s how you should always cross an iced-over bridge, the truck may be slowing, but it’s still pulling on the kingpin, which is always more stable than the trailer pushing on the truck.

What was the root cause of the slide? We’ll never know. I was over an hour south of the freezing precip, with no indications of any freezing for over an hour. It’s possible that was a cold spot the night before, or it could have been something spilled on the road; but it really doesn’t matter. The point is you have to be prepared for the unexpected, and just deal with it. The why is just something to occupy your mind later.
 
Last edited by a moderator:

Rigjockey

In Gord we trust!
I hit black ice in Michigan the truck went to the left. The only thing I could think of was hitting the clutch and steering. I steered a bit too much and the truck was going to the right, I still had the clutch in and managed to steer it straight.
Now the hard part like you said, getting in the right gear and at the right RPM to keep everything neutral.
I am not even going to pretend that I was thinking of all of this at the time, It was just the reaction I made and a lot of luck that it all worked out.

I thought I was going to die of a heart attack.
 

Shreck

Well-Known Member
Premium
full

Unexpected events are what separate the men from the boys. This isn’t based on a real event, it IS the real thing. So I’ll tell a little tale:

I was in Lexington, Ne waiting for my trailer at IBP. It was an ugly week, bunch of loads going places I wasn’t. So Kirby, my dispatcher, offered me a long delivery Amarillo that loaded that day. I jumped on it thinking I’d run through Elk City, Ok, where I’d spend some time with a friend and my brother. Wasn’t real thrilled about time off away from home, but it was by far the best option.

So I’m watching the weather as I cool my heels knowing that IBP just might screw this up. (deadline ship was 2 days away!) There’s a winter storm bearing down on Kansas, freezing rain that night with a day of blizzard conditions following that. I was rather used up, and saw them grab my trailer about 18:00, so I sacked out.

Sometime shortly after midnight, I get the CB call that I’m ready to go. Needless to say, I got my rear in gear and was southbound within the half hour. And shortly after finding Kansas, I found the ice. It was pasable, but slow. I found Oklahoma, and wet roads, around daybreak, and very soon the freezing rain had become a light drizzle. So far, so good.

Now it’s an hour and half later, and I’m making tracks, cruise set about 68, there having been no signs of ice on the grass and trees for over an hour.

(yeah, yeah. I’m being long winded cause I’m bored, so just keep reading! )

Now somewhere south of Woodward there’s a set of 45 degree S-curves that are nicely banked and large radius, so there’s no need to slow down. (been through em on a bike at more than the ton.) I roll through the right and I’ve just stabilized the left when:

“BUTT TO BRAIN! BUTT TO BRAIN! WHAT THE *#$& !”

Now if you’ve been at this a while, you know what I’m talking about. The seat of my pants had just informed me of a unexpected and undesirable yaw event. (the rotation axis of my rig had just shifted well forward)

A quick glance left showed no sign of the trailer. Expected, but unpleasant nonetheless. A right glance showed, yes, you guessed it, trailer. LOTS of trailer. And now for our quiz.

One of these is the right choice, the others will have various unpleasant outcomes. So, do you:

A) lightly apply the brake pedal to slow the truck.

B) use the Johnny bar (trailer brakes) to pull the trailer back in line.

C) disengage cruise to allow truck to slow down

D) disengage cruise, maintain neutral throttle (an in-gear coast)

E) accelerate to pull the trailer back in line.

Hhmmmmmmm…………..

‘A’ and ‘B’ would have similar outcomes. Your trailer tires are already sliding, teetering on the edge of adhesion. Any brake application will almost surely lock them up, reducing their friction (a rolling tire has more traction than a sliding tire, even if it’s rolling with a high slip angle.) and, combined with the slowing tractor, send the trailer swinging to the right. Well, swinging until it ends up in the ditch or smacks your cab in a slow jackknife, anyway.

‘C’ is an iffy choice. As the tractor slows, it’s pushing back against the kingpin. Which would be fine if your trailer was inline. But it’s not, and as you push back, the momentum of the trailer pushes the back-end of the truck forward at the same time it’s also yawing it to the side. Not a good idea! You might get lucky and have enough traction at the tractor to keep it from snapping into a jackknife. But you might not! Do you feel lucky?

‘E’. Well, you know how when you come up on a wreck and the truck and trailer are on their right side, across the road, with the top of the rig facing his former direction of travel. And you wonder, “how’d he do that?” This is how you do that! Nuff said?

Which leaves us with ‘D’. The idea being to minimize the traction you’re requesting from your tires. Some people prefer the ‘push the clutch in and coast’ method, which is basically equivalent to this. Just be careful reengaging that you match RPM or else you might cause another skid, with the tractor this time. I’ve always had a good feel with the throttle and prefer that way. There’s still no guarantee that you won’t further lose control with this technique, but it gives you the best chance of a safe recovery.

And that’s what I did, I kept just enough throttle to keep just the slightest forward pull on the kingpin. Some speed bled off, the trailer slowly came back in line, and away I went! By the way, that is the most stable dynamic state you can have a truck in. It’s how you should always cross an iced-over bridge, the truck may be slowing, but it’s still pulling on the kingpin, which is always more stable than the trailer pushing on the truck.

What was the root cause of the slide? We’ll never know. I was over an hour south of the freezing precip, with no indications of any freezing for over an hour. It’s possible that was a cold spot the night before, or it could have been something spilled on the road; but it really doesn’t matter. The point is you have to be prepared for the unexpected, and just deal with it. The why is just something to occupy your mind later.
That time of year the cruise can get you in a lot of trouble.
 

Hammer166

Instigateur №166™
Premium
That time of year the cruise can get you in a lot of trouble.
It was really a non-issue. The drives never slipped until the trailer had really stepped out. It wasn't power that caused the slide, but cornering force. And like I said, I was well south of any icing when it happened, which is why it was so unexpected.

As a side note, today's trucks with the electronic throttles and ABS are quite sensitive to slippage, both on cruise and Jake. They're good enough that most drivers will hear the reduced throttle/Jake without even realizing they were on the edge of traction. It's not quite as good as a good winter driver, but probably better than most, considering how few drivers get the opportunity to learn real winter driving skills. I'm not suggesting depending on the ECM to catch spins/slides, but it's not the death wish using them in the past was.
 
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mndriver

curmudgeon extraordinare
What was the root cause of the slide? We’ll never know. I was over an hour south of the freezing precip, with no indications of any freezing for over an hour. It’s possible that was a cold spot the night before, or it could have been something spilled on the road; but it really doesn’t matter. The point is you have to be prepared for the unexpected, and just deal with it. The why is just something to occupy your mind later.
S-curve at daybreak?

frost likely on the shady side of the road would be my guess.

so it should have been expected really. Complacency and running on cruise in and at a time of day that should never have had cruise on.
 
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mndriver

curmudgeon extraordinare
That time of year the cruise can get you in a lot of trouble.
My thoughts too.

complacency had him set cruise.

you can be rolling across an interstate at that time of day and the shady areas are pure grease with frost.

look in the ditches and you’ll see scars from past accidents as well. Indicators of others who’ve taken that ride “cruising”…

another sign that the roadways there are dangerous curves…

 

Electric Chicken

Well-Known Member
Premium
Pretty much. I forgot my lowly standing amongst the gods.
IMHO when a trailer kicks out on its own, unprovoked by truck movement, it's just an unfortunate unpreventable occurrence.

I don't care what any safety "manager" or supertrucker says.
 

mndriver

curmudgeon extraordinare
I swear to God this place is as bad as the freaking lunch counter! 🤬

"Everybody knows not to use the cruise blah blah blah..."

The trailer stepped out. No push from the steers, no wiggle from the drives, just the trailer let loose. The cruise is #&#@#& irrelevant to what happened.
The cruise may be irrelevant to what happened …

It’s totally relevant to your reaction.

had you not been on cruise, going to your neutral throttle likely would have just happened feathering it through the curves.
 

Hammer166

Instigateur №166™
Premium
The cruise may be irrelevant to what happened …

It’s totally relevant to your reaction.

had you not been on cruise, going to your neutral throttle likely would have just happened feathering it through the curves.

OH... I see. So I could just have handled by (what was the term you used?) being COMPLACENT. Got it.

The initial state of the throttle doesn't change the fact that one had better know how to react to the situation.
how do you take it off cruise.?
Answer the question. How does his method for returning to neutral throttle matter?
I did answer the question.

what’s the common method for taking a vehicle off cruise…?
You know, actually explaining your thinking, and not playing the cryptic smartest man in the room, which leaves us trying to guess your line of reasoning, would vastly improve the discussion. It would also make it much clearer to those who really could stand to learn some of this information.

Btw, everyone's default method of disengaging the cruise should to toe the clutch pedal and if needed, picking up the throttle at the same instant. That takes the truck to neutral throttle almost instantaneously.
 

Electric Chicken

Well-Known Member
Premium
I don't have a clutch pedal so I always use my foot for throttle in good conditions just in case the trailer finds something to slip on and kick out on me. 🤪
 

Sinister

pari animositate
Staff member
Premium
That time of year the cruise can get you in a lot of trouble.
This picture was in Utah when I drove the day cab to Vegas and back. Zoom in and look toward the driveway. I took this picture from my room at the hotel across the street.
 

4mer Trucker

15 Percenter
Premium
I swear to God this place is as bad as the freaking lunch counter! 🤬

"Everybody knows not to use the cruise blah blah blah..."

The trailer stepped out. No push from the steers, no wiggle from the drives, just the trailer let loose. The cruise is #&#@#& irrelevant to what happened.
Isn't it Ironic that the one's that are most easily offended don't mind doing the offending

Wonder if the Expert considered the bazillion different variables leading up to this event?

The Picture is MIA @Sinister
 

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