Interesting reading next door about being overweight, lots of chat about axle weights, 6x2s v 4x2s etc etc etc
Is there a beginners guide kicking about here somewhere?! Its not something I usually worry too much about - I’m usually 6x2 fridge at about 12t max - but if I hit it lucky some weekend and get a tipper it’d be good to understand what i’m doing…!!
Talulah:
Interesting reading next door about being overweight, lots of chat about axle weights, 6x2s v 4x2s etc etc etcIs there a beginners guide kicking about here somewhere?! Its not something I usually worry too much about - I’m usually 6x2 fridge at about 12t max - but if I hit it lucky some weekend and get a tipper it’d be good to understand what i’m doing…!!
There would probably be too many variations.
The position of the pin, the type of trailer, where the axles were positioned, number of axles, etc etc
But you never know, just because I’ve not come across such a guide does not mean that there isn’t one.
ROG:
Talulah:
Interesting reading next door about being overweight, lots of chat about axle weights, 6x2s v 4x2s etc etc etcIs there a beginners guide kicking about here somewhere?! Its not something I usually worry too much about - I’m usually 6x2 fridge at about 12t max - but if I hit it lucky some weekend and get a tipper it’d be good to understand what i’m doing…!!
There would probably be too many variations.
The position of the pin, the type of trailer, where the axles were positioned, number of axles, etc etcBut you never know, just because I’ve not come across such a guide does not mean that there isn’t one.
It was really general principles i was after - a quick engineering/physics lesson…
Talulah:
ROG:
Talulah:
Interesting reading next door about being overweight, lots of chat about axle weights, 6x2s v 4x2s etc etc etcIs there a beginners guide kicking about here somewhere?! Its not something I usually worry too much about - I’m usually 6x2 fridge at about 12t max - but if I hit it lucky some weekend and get a tipper it’d be good to understand what i’m doing…!!
There would probably be too many variations.
The position of the pin, the type of trailer, where the axles were positioned, number of axles, etc etcBut you never know, just because I’ve not come across such a guide does not mean that there isn’t one.
It was really general principles i was after - a quick engineering/physics lesson…
I think Krankee might be able to help - try a PM to him 
ROG:
Talulah:
ROG:
Talulah:
Interesting reading next door about being overweight, lots of chat about axle weights, 6x2s v 4x2s etc etc etcIs there a beginners guide kicking about here somewhere?! Its not something I usually worry too much about - I’m usually 6x2 fridge at about 12t max - but if I hit it lucky some weekend and get a tipper it’d be good to understand what i’m doing…!!
There would probably be too many variations.
The position of the pin, the type of trailer, where the axles were positioned, number of axles, etc etcBut you never know, just because I’ve not come across such a guide does not mean that there isn’t one.
It was really general principles i was after - a quick engineering/physics lesson…
I think Krankee might be able to help - try a PM to him
Cheers Rog, will do!
There are an awful lot of numbers involved in working this stuff out. I’ll try and outline some of the basics here.
Every truck, be it rigid or artic unit, will have in it a ministry “plate”. This is usually somewhere around the passenger seat/footwell. It details an assortment of maximum weights for the vehicle. This will include:
The maximum permitted weight on each axle, starting with Axle1 which is the front axle and working back to the rear.
The maximum total permitted weight of the vehicle, also known as the MAM (Maxuimum Authorised Mass) or MGW (Maximum Gross Weight).
The maximum total permitted weight of the vehicle and any trailer, also known as the GTW (Gross Train Weight).
For a typical 18ton rigid or 2 axle tractor unit, the axle weights might be 7100kg and 11500kg for the steer and drive axles respectively with a MAM of 18000kg. You are not allowed to exceed any of these weights. As you can see from this the axle weights add up to 18600kg which is higher than the MAM, this gives you some flexibility regarding the position of the load. The nearer the front of the vehicle you put the load the more weight goes on the front axle, the nearer the back the more goes on the back axle. Any load placed behind the back axle will actually take weight off the front axle (think of it as a bit of a see-saw effect with the back axle as a pivot).
When it comes to artics, there are even more numbers that come into play. If we assume a 3 axle unit has plated weights of 7100,7100,11500 and a MAM of 23500kg, which is about typical, you can see that the axle weights add up to 2200kg more than the MAM, this gives you a fair bit of flexibility of where you put the load. The load in this case is the weight placed by the trailer on the fifth wheel, so in practice what it means is the position of the fifth wheel isn’t critical to the weight distribution and people will normally place it such that the trailer is as close as is sensible to the unit in order to get the best possible fuel economy. The maximum gross weight of this hypothetical unit will be anything up to 44000kg. It is not uncommon for a company to have this reduced as reducing the maximum permitted weight means your road tax is cheaper and if you never carry anything heavy that is a worthwhile saving.
The trailer also has a plate with a load more numbers on it. This has the maximum axle weights for the trailer, the maximum weight imposed on the fifth wheel and the maximum total gross weight for the trailer. These weights might be 8000kg for each of the three axles, 15000kg on the pin and a total maximum of 39000kg, for example. If we assume the tractor unit mentioned above is plated at 44000kg GTW and weighs 8500kg including fuel and driver then the 39000kg MGW for the trailer will not ever be an issue as 44000kg-8500kg only leaves 35500kg for the trailer and load anyway. If we assume the trailer weighs 7000kg empty that leaves a payload of 28500kg for the whole setup.
I hope that makes some sense. I could go on all day to be honest, but that’s the basics. When you’re loading a vehicle knowing those basics and having a rough idea of how heavy the pallets on your load are should give you have a chance of spreading the load around in such a way that none of the weights are exceeded.
Paul
repton:
When it comes to artics, there are even more numbers that come into play. If we assume a 3 axle unit has plated weights of 7100,7100,11500 and a MAM of 23500kg,These weights might be 8000kg for each of the three axles, 15000kg on the pin and a total maximum of 39000kg, for example. If we assume the tractor unit mentioned above is plated at 44000kg GTW and weighs 8500kg including fuel and driver then the 39000kg MGW for the trailer will not ever be an issue as 44000kg-8500kg only leaves 35500kg for the trailer and load anyway. If we assume the trailer weighs 7000kg empty that leaves a payload of 28500kg for the whole setup.
I hope that makes some sense. I could go on all day to be honest, but that’s the basics. When you’re loading a vehicle knowing those basics and having a rough idea of how heavy the pallets on your load are should give you have a chance of spreading the load around in such a way that none of the weights are exceeded.
Paul
Have I got this right then…
The unit MAM refers to the max that can basically be put over the front of the trailer - and the balance to get us to the 44t (for example) is what goes over the three trailer axles? Always providing that if the max isn’t over the unit the the weight over trailer shouldn’t exceed 24t (in the example above)?
Talulah:
The unit MAM refers to the max that can basically be put over the front of the trailer - and the balance to get us to the 44t (for example) is what goes over the three trailer axles? Always providing that if the max isn’t over the unit the the weight over trailer shouldn’t exceed 24t (in the example above)?
The MAM of the unit is the total permitted load on the axles of the unit, which is usually either 18000kg or around 23500kg for a 2 or 3 axle unit respectively.
The exact load on each axle in practice will vary, the total maximum axle weights of a typical 44ton setup will be something approaching 50ton so there’s some flexibility in where the load goes.
Paul
If there was no flexibility on each axle then the driver would have to be very pedantic as to exactly where the load went - so much a 1mm out and it would be overweight on one or more axles.
This shows an example…
Axle 1 = 3.4 tonnes
Axle 2 = 5.0 tonnes
Total = 8.4 tonnes
but the maximum allowed in total is the gross weight of 7.5 tonnes.
I think Krankee might be able to help - try a PM to him
repton:
What he said. 