i noticed on my way to sunderland last week that the truck tried to put me through the windscreen every time i turned off a roundabout and thought it was a defect. i was informed today that its a safety feature that applies the brakes trailers to pull it straight as the unit accelerates to prevent a jack-knife. the general feeling between us was that it is a bit touchy which is causing problems when the truck suddenly brakes hard, not only for the poor unsuspecting sod driving it but also for any vehicle behind 
Scanny77 stuck in the dark ages. I think the term you are looking for is called… TRACTION CONTROL or more commonly known as ASR on trucks.
Been around for donkeys years. Stop driving like a tool coming off roundabouts and it won’t happen.
back to the old Rob, passing judgement with absolutely no basis for your criticisms and apparently this time on a system you are unaware of as was i until i was enlightened today
As Rob says, where you been?
scanny77:
and apparently this time on a system you are unaware of as was i until i was enlightened today
Just because you hadn’t heard of it until today doesn’t make it new.
It’s nothing new, our trailers at DHL did that, regardless of the unit pulling it, if you drove it like a fire engine or the road had a bit of a lean to it. Come out of a roundabout a bit lively and you feel the trailer brakes come on. We don’t have those trailers at our place any more.
They’ve had them on Morrisons trailers for ages. Not as bad as you describe Scanny77 but you can feel it pulling you back. Supposed to stop you rolling over aswell.
MikeCunn:
They’ve had them on Morrisons trailers for ages. Not as bad as you describe Scanny77 but you can feel it pulling you back. Supposed to stop you rolling over aswell.
Can you jack knife or roll over doing 35mph? 
i am actually after sensible replies to this, not wishful thinking
bubsy06:
MikeCunn:
They’ve had them on Morrisons trailers for ages. Not as bad as you describe Scanny77 but you can feel it pulling you back. Supposed to stop you rolling over aswell.Can you jack knife or roll over doing 35mph?
You can roll over at relatively low speeds, there is something called slow roll phenomenon.
You could jack-knife at low speeds depending on the road surface. You must have felt a twitch or two and the unit and trailer trying to step out coming off a roundabout after rain, following a long dry spell, when the road is extra greasy.
scanny77:
:lol:i am actually after sensible replies to this, not wishful thinking
Exactly where is the wishful thinking in the replies so far?
Coffeeholic:
bubsy06:
MikeCunn:
They’ve had them on Morrisons trailers for ages. Not as bad as you describe Scanny77 but you can feel it pulling you back. Supposed to stop you rolling over aswell.Can you jack knife or roll over doing 35mph?
You can roll over at relatively low speeds, there is something called slow roll phenomenon.
You could jack-knife at low speeds depending on the road surface. You must have felt a twitch or two and the unit and trailer trying to step out coming off a roundabout after rain, following a long dry spell, when the road is extra greasy.
No, only time I have come close is when I have lost traction in the mud and the unit decides the only way it wants to go is sideways, I solve that problem by stopping and getting a tow off the forwarder driver.
How does slow speed rollover happen?
the other day i actually suspected the exhaust brake. it felt like stage 3 was kicking in as i gave a little power to turn off the roundabouts which took me by surprise considering you turn left then right to go round (going over several roundabouts on the A1231) so why only when turning off? im after decent fuel returns so im light on the pedals these days to keep in the good books (with the exception of that stupid CC policy). despite many journeys with different units and trailers, this has only occurred on 2 journeys for no obvious reason ie not driving fast or making sharp movements
Coffeeholic:
scanny77:
:lol:i am actually after sensible replies to this, not wishful thinking
Exactly where is the wishful thinking in the replies so far?
blaming my driving is wishful thinking and is the easy but incorrect option. we are constantly monitored and reported on at debrief with a grading. besides, if i was driving like a maniac i wouldnt be posting this as i would already understand why the brakes are being applied. on saturday rate i am not rushing anywhere so lets try something more constructive shall we?
bubsy06:
Coffeeholic:
bubsy06:
MikeCunn:
They’ve had them on Morrisons trailers for ages. Not as bad as you describe Scanny77 but you can feel it pulling you back. Supposed to stop you rolling over aswell.Can you jack knife or roll over doing 35mph?
You can roll over at relatively low speeds, there is something called slow roll phenomenon.
You could jack-knife at low speeds depending on the road surface. You must have felt a twitch or two and the unit and trailer trying to step out coming off a roundabout after rain, following a long dry spell, when the road is extra greasy.
No, only time I have come close is when I have lost traction in the mud and the unit decides the only way it wants to go is sideways, I solve that problem by stopping and getting a tow off the forwarder driver.
How does slow speed rollover happen?
It’s all to do with physics and way beyond my understanding. All I know is the risk can be reduced by varying the line into and out of a roundabout as when the exit path is a mirror image of the entrance the chances are higher, or something like that. It’s also more prevalent in certain types of vehicles, here is a report into it and trucks carrying paper reels for instance.
scanny77:
Coffeeholic:
scanny77:
:lol:i am actually after sensible replies to this, not wishful thinking
Exactly where is the wishful thinking in the replies so far?
blaming my driving is wishful thinking and is the easy but incorrect option. we are constantly monitored and reported on at debrief with a grading. besides, if i was driving like a maniac i wouldnt be posting this as i would already understand why the brakes are being applied. on saturday rate i am not rushing anywhere so lets try something more constructive shall we?
It doesn’t have to be because of speed, it can happen if the trailer has a bit of a lean to it because of the load, or the camber of the road, or just the way the trailer leans one way and another as you go through the roundabout. If the thing senses a certain degree of a lean it thinks you may be going over and applies the trailer brakes. As with the post above if you can vary the entry and exit path, so they are not alike, it reduces the chance of too much lean and the chance of this thing kicking in.
Is this a stupid reply ?
John Lewis trialed a similar system on their new double deck trailers to prevent roll overs. The trailer brakes alone are activated to slow the vehicle down if it thought you were taking a bend too quickly. I didn’t realise the trailer brakes were applying though I did notice it could be a little sluggish at pulling out of bends after a roundabout - that was until I pulled into the yard at MK Blakelands and could smell the trailer brakes cooking away 
I protested my innocense, and the manager told me that the system was too sensitive on some trailers and the project was likely to be ditched.
I have felt the Volvo’s traction contol system in action, can be rather annoying as it does jump at the slightest wheel slip, but it’s nice to know it’s there, possibly saving you from a “well boss…” moment.
The Volvo TC system is crap, On muddy forest tracks I have to turn it off to get traction
scanny77:
the other day i actually suspected the exhaust brake. it felt like stage 3 was kicking in as i gave a little power to turn off the roundabouts which took me by surprise considering you turn left then right to go round (going over several roundabouts on the A1231) so why only when turning off? im after decent fuel returns so im light on the pedals these days to keep in the good books (with the exception of that stupid CC policy). despite many journeys with different units and trailers, this has only occurred on 2 journeys for no obvious reason ie not driving fast or making sharp movements
i think you will find this system is nowt to do with volvo or traction control
it sounds to me like a trailer stability system to try to stop overturns, i have had this on trailers in the past but i was never v keen as there is to much delay, the system must work on weight transfer on the suspension and as you say when exiting a rounabout the brakes apply just as your foot is down to speed up !
result hot brakes and a hit on the fuel returns
bubsy06:
MikeCunn:
They’ve had them on Morrisons trailers for ages. Not as bad as you describe Scanny77 but you can feel it pulling you back. Supposed to stop you rolling over aswell.Can you jack knife or roll over doing 35mph?
i rolled over a rigid at 30mph. 
Sent from my GT-I9100 using Tapatalk
Moose:
scanny77:
the other day i actually suspected the exhaust brake. it felt like stage 3 was kicking in as i gave a little power to turn off the roundabouts which took me by surprise
i think you will find this system is nowt to do with volvo or traction control
it sounds to me like a trailer stability system to try to stop overturns, i have had this on trailers in the past but i was never v keen as there is to much delay, the system must work on weight transfer on the suspension and as you say when exiting a rounabout the brakes apply just as your foot is down to speed up !
result hot brakes and a hit on the fuel returns
Yup its a trailer stability system - but its not adjusted right - simples
we had this on the new DHL trailers about 4-5 years ago - it was good but it didn’t push you towards the screen - it was a bit scary though as i always thought the red line had gone - once they adjusted it on the trailers we had no more problems
regards
Steve