Incredible film quality on that clip for the time looks like it could have been filmed yesterday.
Don’t know what all the fuss is about. All you need is a generous coat of anti jacknife grease on the 5th wheel, the kind that allows slow movement but locks solid under sudden load. Been using it for years. Never had a jacknife yet.
WhiteTruckMan:
Don’t know what all the fuss is about. All you need is a generous coat of anti jacknife grease on the 5th wheel, the kind that allows slow movement but locks solid under sudden load. Been using it for years. Never had a jacknife yet.
I’ll have a pint of whatever you’ve been drinking!
i think he was having a pop at the truck in the video, that would only go to 45* before locking up…
newmercman:
WhiteTruckMan:
Don’t know what all the fuss is about. All you need is a generous coat of anti jacknife grease on the 5th wheel, the kind that allows slow movement but locks solid under sudden load. Been using it for years. Never had a jacknife yet.I’ll have a pint of whatever you’ve been drinking!
Yeah, I pretty much thought I wouldn’t be able to slip that old chestnut past the forum, but it was worth the try 
WhiteTruckMan:
newmercman:
WhiteTruckMan:
Don’t know what all the fuss is about. All you need is a generous coat of anti jacknife grease on the 5th wheel, the kind that allows slow movement but locks solid under sudden load. Been using it for years. Never had a jacknife yet.I’ll have a pint of whatever you’ve been drinking!
Yeah, I pretty much thought I wouldn’t be able to slip that old chestnut past the forum, but it was worth the try
[emoji1787][emoji1787][emoji1787][emoji1787]
Strictly speaking, a tanker is the least likely lorry to jackknife from the drive axle going light as the slosh of the liquid within will shift weight over the pin to counteract the weight transfer to the front axle.
I think…
nomiS36:
https://youtu.be/BwA2UdpEaMc
1.37 - 1.54
2.39 - 2.56
Which is why the Americans removed the brakes from the steer axle. 
I managed to do this on the A68 just south of Tow Law at 4am on New Years Day 2018
Travelling north on the A68 a nice clear morning , no mist , one of those really enjoyable driving days then, it all goes pear shaped .
Moving out from the edge of the road to avoid some bumps / bad surface the units drive wheels lost traction on the white lines starting a ‘lazy’ slide , corrected it , then again then a third time and I was a passenger .
When it had all stopped going ‘■■■■ up’ I was facing the way I had come , almost a parallel park with my nearside wheels on the grass verge warning lights and buzzers all coming from the dashboard .
I got out of the cab and stepped onto an ice rink , showing 7 degrees on the dash but this short stretch was black ice with a touch of diesel …lovely .
Lots of police arrived , they saw how bad it was , one of the women police officers was running and sliding to show how slippy it was .
The truck had jacknifed at some point the scars on the side of the trailer and unit showing where they had met .
Not sure whether the EBS/ ABS traction control and stability control helped but completely spinning an artic with only superficial damage on the A68 has got to be a good thing.
What struck me was the quality of the commentary: clear, accurate, understandable and well-informed…you would just get a steam of squeals and nonsense from one of today’s presenters.
At what point did the TV industry decide all viewers were morons, and the presenters had to operate at the same level.
I have a dim memory of the Hope Anti-Jackknife Device…did my memory just make it up, or was it really a thing?
GasGas:
What struck me was the quality of the commentary: clear, accurate, understandable and well-informed…you would just get a steam of squeals and nonsense from one of today’s presenters.
At what point did the TV industry decide all viewers were morons, and the presenters had to operate at the same level.I have a dim memory of the Hope Anti-Jackknife Device…did my memory just make it up, or was it really a thing?
Totally agree about the commentary.
Wasn’t the Hope device like a brake drum on the fifth wheel? I never saw one in the flesh.
If you were on a bend and braked you couldn’t straighten up, was the charge against it.
As I say no experiences personally
GasGas:
What struck me was the quality of the commentary: clear, accurate, understandable and well-informed…you would just get a steam of squeals and nonsense from one of today’s presenters.
At what point did the TV industry decide all viewers were morons, and the presenters had to operate at the same level.I have a dim memory of the Hope Anti-Jackknife Device…did my memory just make it up, or was it really a thing?
Agree
newmercman:
Strictly speaking, a tanker is the least likely lorry to jackknife from the drive axle going light as the slosh of the liquid within will shift weight over the pin to counteract the weight transfer to the front axle.I think…
The slosh of 20+ tonnes of liquid going forward is what will actually cause the jacknife to occur.
No, the slosh when it goes back and lightens the imposed load on the kingpin would do that, but all the while the vehicle is braking hard there will be no sloshing, the liquid will all be at the front. Try it with a drink bottle, the slosh back doesn’t happen until you stop.
newmercman:
No, the slosh when it goes back and lightens the imposed load on the kingpin would do that, but all the while the vehicle is braking hard there will be no sloshing, the liquid will all be at the front. Try it with a drink bottle, the slosh back doesn’t happen until you stop.
The problem being that much of the weight is going in a forward direction against the bulkhead and possibly baffles not a downward one and thereby trying to rotate the rear of the unit vertically over the braked front axle.Then it pushes the unloaded drive axle laterally out of the way as the trailer still tries to overtake the braked steer axle.As for the rearward slosh removing weight from the pin again the Americans found the answer to both problems by often just abandoning artic tankers as a bad idea altogether.Especially where there’s mountains needing to be climbed and descended.
There’s a lot more artic tankers in the US than wagon and drags. They’re mostly smooth bore too, they don’t do baffles, a single pot with a central lid to make washing out easier. Luckily most seem to be dedicated to one substance, so they don’t have much room for sloshing as they build them to spec.
I’ve not done much tanker work personally, but my Dad was on tanks for years and I grew up on them. I also did tippers full of guts that slish around and in my experience any sloshing back happens when you come to a stop or make abrupt gearchanges pulling away. Slamming on the anchors with a tipper full of guts sends the whole load forwards snd it definitely puts more weight on the pin as I could hear my wing tops rubbing on the tyres until the air suspension caught up with the extra weight on the drive axle.
When the deadman lever was fitted to artics, late sixties, early seventies, a judicious application of that lever instead of the service brakes would correct 99% of jack knife situations if the driver had the presence of mind to use it.
newmercman:
There’s a lot more artic tankers in the US than wagon and drags. They’re mostly smooth bore too, they don’t do baffles, a single pot with a central lid to make washing out easier. Luckily most seem to be dedicated to one substance, so they don’t have much room for sloshing as they build them to spec.I’ve not done much tanker work personally, but my Dad was on tanks for years and I grew up on them. I also did tippers full of guts that slish around and in my experience any sloshing back happens when you come to a stop or make abrupt gearchanges pulling away. Slamming on the anchors with a tipper full of guts sends the whole load forwards snd it definitely puts more weight on the pin as I could hear my wing tops rubbing on the tyres until the air suspension caught up with the extra weight on the drive axle.
However you look at it they definitely came to the ( probably correct ) conclusion,that the net effect of the forward movement of any semi trailer, fighting against a braked steer axle,was firstly that it lifts weight of the drive axle,by trying to revolve the rear of the unit vertically over the steer and then tries to push the unit sideways out of the way as it tries to overtake the braked steer.Which was also more or less what the documentary said.Also imagine the forces acting on the steer axle anchorages at that point.
The simple solution being get rid of the steer axle brakes.( Obviously more viable in the case of their general unit axle configuration ). 
gingerfold:
When the deadman lever was fitted to artics, late sixties, early seventies, a judicious application of that lever instead of the service brakes would correct 99% of jack knife situations if the driver had the presence of mind to use it.
Triaxle semi trailers would obviously also have helped in providing more braking capacity and grip from the trailer and reducing the forces acting on the unit.