This YouTube video shows how slowly you can be going and still fall over, usually down to loads shifting. Obviously some of the clips show complete morons going so fast and/or violently over steering it makes you wonder if they’re deliberately trying to turn over.
youtu.be/fkSlzTZR_ic
wanderingstar:
cav551 that is very interesting about how the right speed to roll over can sometimes be slow. I do roundabouts at about 14mph in the double decker and think I’m therefore safe but it sounds maybe not!Santa I didn’t know ripping tyres off by screwing trailers round on concrete was a ‘thing’. I’ll bear that in mind when I’m on the small tyres! And I hadn’t thought about the small wheels helping with the CG either.
nomiS36 food for thought that picture!! Esp. with bridges…
And thanks everyone else for the brilliant info and advice. I knew TN would sort me out with this!
I might be reading this wrong, so ignore me if that’s the case, but don’t fall into the trap of using your speedo to decide whether you can corner safely or not. Use your eyes and bum on the seat to judge it.
This piece of advice might be wrong, I’m sure a more experienced driver can weigh in if so! … If you feel a sort of “nudge” or “wobble” through the cab as you straighten up and turn the steering the other way, you’ve done it too fast for that corner + load combination.
Anyone delivered to wickes Oldham?
Not the best goods in set up. You have to drive up a side road, then put your trailer up the kerb to point it towards the gates to the yard, but on top of that the camber of the road isn’t exactly flat. Double stacked board on the trailer and your looking at the angle of the trailer as it goes up the kerb, that coupled with the fact because your reversing your pushing the trailer into the lean of the road…
Was one of those moments where I thought this ain’t good, should I abort? Only reason I carried on was because I knew they had artic deliveries there all the time and the wickes own trailers are DDs.
Probably didn’t look as bad from outside but watching the lean in the mirrors a heart skip a beat moment
High c.o.g with DD’s are obviously the problem with needlessly tall trailers, couple that with more chance of load shifting up top and its a recipe for disaster overspeeding at roundabouts let alone clipping a kerb. Low c.o.g with a load thats akin to be permanently fixed to the trailer floor and tyre shredding speeds around roundabouts (not that i do that) wont be a problem.
Surprised the UK govt even allow these things on the road…
fingermissing:
Harry Monk:
Where’s that video of the Downton’s truck going over in a brewery somewhere because the driver dragged the trailer wheels over a kerb?just for harry
m.youtube.com/watch?v=DNrPEfiJRTk
He hits that at some speed 
I drive 15’ 11" ones overnight and have bumped a few but really recommend not doing so. The low height curbs seem to be alright but anything like pavement height would be buttock clenching.
You’ll spend more time worrying about winds, roundabouts and other drivers doing stupid stuff in front of you.
Strap stuff properly! Eg, IBCs must be properly strapped not just using internals, unless empty, as they slide when cornering and thats what will cause you to go over regardless of what others at the depot say.
I remember spotting this some time ago. Even with the warning, the hero brigade go tear arsing round.
I’ve never driven a double decker and hopefully never will, I’d be more worried about how they’re loading it…heard a few times about milk or yoghurt on the top deck and toilet paper on the lower deck and first roundabout it’s over on its side…
onyerbike:
I’ve never driven a double decker and hopefully never will, I’d be more worried about how they’re loading it…heard a few times about milk or yoghurt on the top deck and toilet paper on the lower deck and first roundabout it’s over on its side…
They really aren’t that bad tbh. I’ve pulled a fair few and never once felt unstable in normal conditions. I’ve even pulled them in moderately windy weather and not really had issues. Driven properly and sensibly they aren’t that bad. Keep off the curbs is the key, not difficult is it■■?
nomiS36:
onyerbike:
I’ve never driven a double decker and hopefully never will, I’d be more worried about how they’re loading it…heard a few times about milk or yoghurt on the top deck and toilet paper on the lower deck and first roundabout it’s over on its side…They really aren’t that bad tbh. I’ve pulled a fair few and never once felt unstable in normal conditions. I’ve even pulled them in moderately windy weather and not really had issues. Driven properly and sensibly they aren’t that bad. Keep off the curbs is the key, not difficult is it■■?
From the state of some of the drivers I’ve come across in the last few years I’d say they have enough trouble keeping it on the road!
Like you say though, it shouldn’t be difficult!
Properly loaded stepframe decker will be as stable or more stable than a regular trailer loaded floor to ceiling.
These styles of DD are even more stable, the top deck is actually only a couple of foot higher than a regular deck.
Own Account Driver:
Properly loaded stepframe decker will be as stable or more stable than a regular trailer loaded floor to ceiling.These styles of DD are even more stable, the top deck is actually only a couple of foot higher than a regular deck.
A ‘step’ in the right direction but…could be lower (with more stability) with a low profile fifth wheel without a chassis plate and smaller twin wheels rather than SS’s.
Still look pretty hideous things though…
AndrewG:
Own Account Driver:
Properly loaded stepframe decker will be as stable or more stable than a regular trailer loaded floor to ceiling.These styles of DD are even more stable, the top deck is actually only a couple of foot higher than a regular deck.
A ‘step’ in the right direction but…could be lower (with more stability) with a low profile fifth wheel without a chassis plate and smaller twin wheels rather than SS’s.
Still look pretty hideous things though…
Look on the bright side, you won’t be going over a high kerb with one.
AndrewG:
Own Account Driver:
Properly loaded stepframe decker will be as stable or more stable than a regular trailer loaded floor to ceiling.These styles of DD are even more stable, the top deck is actually only a couple of foot higher than a regular deck.
A ‘step’ in the right direction but…could be lower (with more stability) with a low profile fifth wheel without a chassis plate and smaller twin wheels rather than SS’s.
Still look pretty hideous things though…
Guessing you’ve never pulled one as they lower right down so the whole bottom of the trailer is on the floor with no air in the suspension the wheel size doesn’t make any difference it doesn’t have solid axles it’s essentially a similar design to a car transporter. The centre of gravity is very low.
I suspect Mr Tesco would be more concerned with how many roll cages it holds rather than what it looks like.
Captain Caveman 76:
AndrewG:
Own Account Driver:
Properly loaded stepframe decker will be as stable or more stable than a regular trailer loaded floor to ceiling.These styles of DD are even more stable, the top deck is actually only a couple of foot higher than a regular deck.
A ‘step’ in the right direction but…could be lower (with more stability) with a low profile fifth wheel without a chassis plate and smaller twin wheels rather than SS’s.
Still look pretty hideous things though…Look on the bright side, you won’t be going over a high kerb with one.
When there was a road closure and I had to u-turn with one the tail-swing grounded out on the tiniest grass verge you’ve ever seen. I had to get out and faff about raising the suspension to free it in the midst of traffic gridlock. Pulled them for City Link, they spent a fortune on those trailers then decided they wanted to move back to forklifting stillages out of curtainside DDs and ditched them all. The curtainside DDs were several MPG worse on fuel too due to extra height and drag from the curtains.
^^^
Can imagine it could in certain circumstances re a real mare to screw round. Re the fuel consumption, with brick wall esq aerodynamics its only going one way…^^^^
AndrewG:
The trouble with steel rims. Alloy rims like Alcoas are 4 times as strong and wont buckle like that…
They’ll just crack and crumble to pieces. Just fyi, if you ever get a chance to see some irl.
Thanks for the video nomiS36. You’re right, some of them just look like they’re driving more or less normally. What I noticed too is how when the back of the trailer slowly goes over first, then the twist travels up the trailer, then finally screws and slams down the cab at speed.
slowlane - I like that that tip - thanks. Using intuition rather than just ‘rules’.
trevHCS ‘IBCs must be properly strapped not just using internals’ - what do you mean by properly strapped and not just internals in this case?
Captain Caveman 76 - that sign is quite a wake-up call! I had no idea how common it could be.
AndrewG ‘A ‘step’ in the right direction but…could be lower (with more stability) with a low profile fifth wheel without a chassis plate and smaller twin wheels rather than SS’s.’ - another naive question I’m sure, but what is a chassis plate in this case?
Once again thanks to all.
^^^^
A chassis plate fits between the chassis rails and the fifth wheel is bolted to it. Plates come
in various heights.
My FH is fitted with a low profile forged aluminium fifth wheel made by SAF in conjunction with Alcoa which requires no additional chassis plate. It does require open rear arches as the bottom of the trailer is only a few cm above the tyres but…makes for better aerodynamics as a 4M tilt now sits well below cab height…
Brilliant thanks - sounds like a serious piece of kit!