Right, so I’m driving a Scania R440 in a certain company’s Green livery, pulling a certain supermarket’s 10 metre rear steer fridge.
With a loaded trailer, the weighbridge tells me that my steering axle is always overweight by about 1-200 kilos. So I drop the lift axle, go back round and weigh it again and it’s still quite high, about 6.8t, and the back axles are on about 3-4t each. Given that my train weight ends up around 19t, and the kingpin on the trailer so far forward it’s almost underneath the fridge, is the weighbridge telling porkies?
And also, if the steering axle is overweight, wouldn’t the lift axle come down by itself? Or does that only happen if the drive axle is over weight?
If you mean that your gross weight is 19 tonnes, I can’t understand how you could possibly be overweight on any axle, especially as you mention a lift axle which suggests that the unit is a 6x2.
Even if you mean that you have a 19 tonne payload, I just can’t see how that would overload a 6x2 tractor unit
Are you establishing a steady crawl speed before starting the weighing, the slight kangarooing that accompanies the crawl settling down can produce large discrepencies…not being patronising here despite it maybe sounding like, i’ve had to do second runs over the bridge meself when i’ve started the crawl up too close to the weigher.
Otherwise as above, have you tried pushing the 5th wheel back a couple of clicks and see how she fares, as an aside i’ve always found normal tractors to be more stable with the 5th further back anyway, some companies have a set position they insist you use even if the 5th is a slider so you maybe don;t have that option.
Its quite surprising just how little the steer axle weight varies from empty to loaded, even completely empty there’s still around 6.3 or so tons showing when i tare off, even when running at a full 44 tons that same steer axle has only raised to just under the legal maximum.
Something doesn’t really sound right on a 6x2 even if they’ve loaded the front with masses of fruit juice and the back with bog rolls. As mentioned slide the fifth wheel back a few clicks.
Juddian:
as an aside i’ve always found normal tractors to be more stable with the 5th further back anyway, some companies have a set position they insist you use even if the 5th is a slider so you maybe don;t have that option. just under the legal maximum.
Yes I’ve always found that sliding the fifth wheel right forward for closer coupling, with fuel economy being the rationale, often results in a less comfortable ride and worse traction. Although the overall vehicle length is shortened I often think there’s an effect of reversing seeming harder work that I’m not imagining.
can you set it out so we can understand it a bit easier.
eg:
first weight with lift axle up.
steer axle weight…7 tons
lift axle weight…0 tons
drive axle weight…8 tons
I think the mid lift only comes down if your over weight on the pin/drive axle as thats where the sensors are … But even then when everything settles down sometimes it will let you still raise it up after if has come down on its own.
I still can’t see how you would be over weight on the drive axle though on a 10M twin axle trailer with a 6x2 unit, and as you said the pin is more further forward as well.
billybigrig:
Perhaps diet and exercise are required
Cheers dude!
cav551:
Sliding 5th wheel?
Nope, it’s a 6x2 Scania R440 with a midlift and no slider.
kindle530:
i dont know if im reading it right, but isnt a 10mtr trailer with a rear steer axle a tandem, rather than a triaxle trailer?
Yep.
limeyphil:
can you set it out so we can understand it a bit easier.
eg:
first weight with lift axle up.
steer axle weight…7 tons
lift axle weight…0 tons
drive axle weight…8 tons
second weigh with lift axle down.
cheers.
Will try to write them down next time I’ve got one on.
FarnboroughBoy11:
I think the mid lift only comes down if your over weight on the pin/drive axle as thats where the sensors are … But even then when everything settles down sometimes it will let you still raise it up after if has come down on its own.
I still can’t see how you would be over weight on the drive axle though on a 10M twin axle trailer with a 6x2 unit, and as you said the pin is more further forward as well.
I’m overweight on the front steering axle, not the drive axle.
lankyphil:
Right, so I’m driving a Scania R440 in a certain company’s Green livery, pulling a certain supermarket’s 10 metre rear steer fridge.
With a loaded trailer, the weighbridge tells me that my steering axle is always overweight by about 1-200 kilos. So I drop the lift axle, go back round and weigh it again and it’s still quite high, about 6.8t, and the back axles are on about 3-4t each. Given that my train weight ends up around 19t, and the kingpin on the trailer so far forward it’s almost underneath the fridge, is the weighbridge telling porkies?
And also, if the steering axle is overweight, wouldn’t the lift axle come down by itself? Or does that only happen if the drive axle is over weight?
dew:
Not sure how the trailer can really send you overweight on the front steer, I thought you meant rear steer on the trailer.
Wasn’t you I passed in Windermere around quarter to 7 this morning was it?
Not guilty, rest day today.
Overall, the only reason that I can think is that when the lift axle is up, the weight/centre of gravity moves forward somehow? Therefore over loading the front axle?
dew:
Not sure how the trailer can really send you overweight on the front steer, I thought you meant rear steer on the trailer.
Wasn’t you I passed in Windermere around quarter to 7 this morning was it?
Not guilty, rest day today.
Overall, the only reason that I can think is that when the lift axle is up, the weight/centre of gravity moves forward somehow? Therefore over loading the front axle?
Fair enough, was an R440 with the Tesco mini trailer. Makes me laugh as it’s usually a Topline, it looks taller than it is long!
when i got pulled down at ringwood one day i knew i was over weight as had left site at 44.750 kg they took me over the bridge and then told me to carry on, as i was only 2% over on my axel weights and vosa won’t prosecute unless your more than 10% over, up to 5% no action, 5 to 10% warning letter, and as said over 10% fine.
now if like my scania your front axel weight should be 7100kg, so if you are 1-200 kgs over thats its just not worrying about as 710kg is 10% over, so 355kg is 5% over, 177.5kg is 2.5% over, and i can’t see how a short trailer like that would put you over!!! i think your axel bridge is knackard
billybigrig:
Perhaps diet and exercise are required
Cheers dude!
cav551:
Sliding 5th wheel?
Nope, it’s a 6x2 Scania R440 with a midlift and no slider.
kindle530:
i dont know if im reading it right, but isnt a 10mtr trailer with a rear steer axle a tandem, rather than a triaxle trailer?
Yep.
limeyphil:
can you set it out so we can understand it a bit easier.
eg:
first weight with lift axle up.
steer axle weight…7 tons
lift axle weight…0 tons
drive axle weight…8 tons
second weigh with lift axle down.
cheers.
Will try to write them down next time I’ve got one on.
FarnboroughBoy11:
I think the mid lift only comes down if your over weight on the pin/drive axle as thats where the sensors are … But even then when everything settles down sometimes it will let you still raise it up after if has come down on its own.
I still can’t see how you would be over weight on the drive axle though on a 10M twin axle trailer with a 6x2 unit, and as you said the pin is more further forward as well.
I’m overweight on the front steering axle, not the drive axle.
Yes sorry I meant front steer axle. The point I was trying to make is that the pin is so far forward on those shorter trailers so that most of the weight would be at the back of the unit more so than if it were a standard deep pin (further back)
I went on a weighbridge that showed me as 14.330kg before I loaded, when I had tipped I was 15360kg. There are variances with weighbridges, some bigger than others.
It is the position of the 5th wheel in relation to the axles that determines the distribution of the unit’s axle weights. The position of the trailer pin only effects the total amount imposed onto the unit and thence the now greater, or lesser axle weights.
