These 16ft plus double deckers which are commonplace on all the pallet distribution networks. How stable are they?
There was a video on YouTube I saw ages ago which showed them testing an old London bus with a fully loaded top deck of passengers and an empty bottom deck. The angle of tilt was ridiculous before it went over.
I was behind a DD pallet line trailer tonight and only on completely normal cambers, motorway tramlines etc, you could really see the top leaning what looked like quite a lot. Just got me thinking, how stable are they really? Is there any legal amount they have to be able to lean like the bus (assuming the top deck isn’t over loaded of course)?
Ours are very stable (major supermarket) but they are loaded properly. Top deck is pretty much pallets of bog roll, nappies and a few eggs. Bottom deck and swan neck, pallets of booze, cans/jars etc.
Having done pallet work too, those are a lot worse. Forkies at the hub really dont care what goes where, if theres a space it gets shoved in it. Seen them trying to load pallets of bricks on the top deck! Forget the 10 ton max on the top deck, if it fits and its on, its gone.
The likes of M&S , John Lewis type of box double deckers gain stability due to the axles being fixed higher than a standard trailer, which puts a lot of the weight below the centre of gravity.Obviously it would not be recommended to operate with the top deck over loaded.
Curtain type double deckers are only as stable as in the way they are loaded.
Double Decker buses were lightweight bodies but solid construction with tall cross ply tyres and leaf springs. The modern DD is articulated, top heavy with air suspension and car sized tyres.
As Fuzrat says loaded properly and driven sensibly they are as stable as most trailers. Ours are loaded with care and the forktrucks in the depot weigh the pallets as they go so I’ve not known a top deck overloaded out of depot. Coming back from stores the top isn’t usually loaded as the stores don’t have weighers on the forklifts & weights can be unknown.
It’s worth noting that the lower deck behind the swan neck is about 18-24" lower than a standard deck which lowers the centre of gravity a bit. Empty you can get buffeted a bit but not to bad as a rule. You can get paranoid about bridges & high kerbs but I find that containers need just as much care & caution, stability wise, when first picked up as most are sealed and the loading is unknown.
At my one and only visit to Pallet ways at Fradley I saw a shunter zooming a double decker around with curtains open and the structure moved like a ■■■■■. I guessing in an impact no amount of straps is going to stop them disintegrating.
jakethesnake:
They are stable if driven correctly and at the correct speed.
The one I’m referring to that I was behind this morning just seemed to be leaning an awful lot just as the wheels went in the uneven bits in a straight line on the M6. Made think if it’s doing that in a straight line then how stable actually are these things on corners/roundabouts
We’ve got a few deckers and can’t say that I’m a fan of them.
They’re ok as long as you don’t take liberties with them.
Drive the as though it’s a live load.
If I have to go out with one I have to go out with it but I’d rather not.
Never had any trouble with them, probably on a par with car transporters which can be pushed pretty hard before things get out of hand, don’t take the ■■■■ and all will be fine.
Where problems can occur is when too much weight is plonked on the arse end, and you get the tail wagging the dog (though this applies to any vehicle), they shouldn’t get out of hand like a car transporter can (bad as caravans when loaded poorly and have been quite a few rollovers over the years due entirely to this) but any instability/swaying due to rear heavy loading should be sensed by the driver.
Went out yesterday fully loaded, and was surprised at just how stable they are, when fully loaded on the top deck and all.
It is all about “center of gravity” of course.
If you go around roundabouts on the edge of your (now better than old) wheels - then the moment the top deck lists out beyond the sides of the base - it is going to go over.
Guess who’s driving with kid gloves, much to the disgust of “up my arse fred” who don’t like the way I shut them out when negotiating roundabouts…
I drive curtainsiders double deckers loaded with pallets every night - usually 15’ 9 and 15’ 11. You do have to watch the top loading but they seem pretty stable for the most part surprisingly.
Roundabouts aren’t usually a major problem unless you take them at stupid speeds, but there are some junctions like for example M62 to M61 where you have to be careful. If it says max 50 then stick to that as they feel worse if it leans for a long time.
Some of the solid siders seem to tip bit i suspect its partly because they dont flex. Theres a surprising amount of flex in the curtainsiders when loaded with IBCs. Do strap up however as you really dont want 1T IBCs shifting on a high trailer.
One advantage is they have stabilising systems on them so if you do take a corner too quick it’ll in theory brake the ABS as long as people plug in the ABS / EBS lead. It only does so much however so best not rely on it.
Oh and yeah, do remember to lookup before passing under bridges.
one that used to visit fradley was a three deck ideal for the traffic into the hub all short light pallets, stopped by the police one night on the homeward leg due to the unstable look when cornering, seven tonnes was taken off the top deck mostly paving slabs.
Thats the problem at the pallet hub, most of the tall pallets are light and the short ones are heavy. Tall boxes of plastic cutlery for bidvest? on the swan neck, short pallets of bricks/slabs? stick them up top. Pallets of lead flashing? only 2ft high so up top, doesnt matter that it weighs a ton on a euro pallet. Half a dozen of those with some bricks and other stuff makes it interesting to say the least.
I used to watch them load and tell them to shift stuff I wasnt happy with but most just dropped trailer, parked in the corner for a 3hr kip, hooked it back up, pulled the curtains and away. Nina the strap-on bird would have wet her knickers at most of the wagons leaving Coalville of a night.
