Dumb question, GVW and GTW

NEW AND WANNABE DRIVERS (INTERACTIVE)
1

Hey, was looking through second hand tractor units on ebay, not planning on buying one any time soon, just curious, and I saw one and decided to check its reg on the DVLA. It says it GVW is 14440kg, which seemed a little light considering it was pictured with a single axle curtainsider on it. How exactly does the GVW and GTW work on a tractor unit? I know there’s a maximum weight allowed per axle, and for example this rig in theory would only allow up to 26t, but are the maximum weights universal depending on the axle set up or are there rigs that can’t take the 26t maximum for example?

On a car or van its straightforward, look up the gtw and that minus the gvw is how big a trailer you can chuck behind it. I assume it works a bit differently on tractor units as a lot more of the trailer weight is sat on the vehicle. Any clarification on this?

2

When hitched up to a trailer the unit cannot weigh more than the GVW and the total of the unit and trailer combined cannot weigh more than the GTW

Also none of the axle weights on the unit or trailer must exceed their max limits

3

FTBlunder:
are the maximum weights universal depending on the axle set up or are there rigs that can’t take the 26t maximum for example?

This may be of interest to you.

A Simplified Guide To Lorry Types and Weights

4

I’ve seen the simplified guide before, I know what the maximum allowances are per axle configuration, but is this universal to all single axle tractor units for example? Can this 14.4t tractor unit weigh up to a maximum of 26t as long as the weight sat on the fifth wheel and the unit itself doesn’t exceed 14.4t? Or will the vehicle plate have a lower limit on it?

Forgive my apparent dumbness, I’m just trying to work out how it works on these things.

5

universal

If the unit has a GVW of say 14 tonnes and it weighs 7 tonnes empty then it can have a max of 7 tonnes put onto the fifth wheel plate by the trailer

6

Ok that clarifies it, thanks. So the weight on the fifth wheel is effectively the equivalent of nose weight on a ball hitch, only measured in tonnes rather than kilos, and any 2 axle tractor unit can have a GTW of 26t.

7

FTBlunder:
Ok that clarifies it, thanks. So the weight on the fifth wheel is effectively the equivalent of nose weight on a ball hitch, only measured in tonnes rather than kilos, and any 2 axle tractor unit can have a GTW of 26t.

Why 26T ? - that would be correct for a single axle trailer as it makes 3 axles in total but will be a higher GTW if the trailer has more than one axle

8

Just as an example, I’m aware with more axles you can have more weight, up to 40t on a 2 axle unit with a tri axle trailer according to the guide.

9

A tractor unit with a GVW of fourteen tons could not operate legally at 26tons GTW with a single axle trailer. As the trailer axle would have to weigh twelve tons which, as far as I know , would make you a very naughty boy!