Maximum permissible mass for my Kia Sorento - getting a bit confused about the figures

[BigTim]

I am getting a bit confused about the weight figures for my 2007 Kia Sorento Titan. It has a maximum permissible mass of 2670Kg. I understand this to be the maximum weight the vehicle is allowed to weigh when fully loaded and the load it is permitted to carry is the MPM minus the mass in service (2196Kg)

What does the Mass in service figure include? Is mass in service the same as kerb weight?

IN PARTICULAR does the MPM include the noseweight of the caravan when it is hooked up to the car, eg, if my caravan has a noseweight of 90Kg do I need to subtract this from the MPM to find the load I am allowed to carry in the car?

I have been checking the weights of my caravan and car with a, recently purchased, Reich Caravan Weight Control and I have been getting a bit confused.

Tim

 

[Lutz]

Whether Mass in Service (also known as Mass in Running Order) is the same as kerbweight depends a bit on how you define kerbweight. The definition of Mass in Service is very specific and includes 75kg for the driver and sundry items and a 90% full fuel tank. Kerbweight conventionally does not include the driver, but on the other hand it does include a 100% full fuel tank. However, some sources actually mean Mass in Service when they refer to kerbweight, so the term 'kerbweight' is open to interpretation.
MPM certainly does include the noseweight, so if you want to know how much payload you can put into the car when towing you have to deduct the noseweight from the MPM.

 

[ProfJohnL]

High Tim,

Your question makes me wonder if you are trying to work out your payload (MPM-MIRO = payload).

The theory is fine, but the practice is often different for a couple of important reasons.

Firstly most cars when you receive them have some optional items fitted that will make the car heavier than its MIRO figure.

These are things like:-
Tow hitch assembly
Paint work - Some paints weigh more than others,
Tyres - a different brand may be a different weight
Wheels, - choice of rims (size and or materials)
In care Entertainment - some high powered speakers can be more than twice as heavy as lesser units, and the same with power amplifiers
Seating material - leathers are heavier than most other materials
carpets - rubber mats can be quite heavy
Extra middle head restraint on the rear seat
Luggage cover.
Bull bars
Extra spot lights
(Nodding dog and furry dice etc)

Its very easy to add 40 to 50Kg of extra weight to what is a car in essentialy its MIRO condition

Because the MPM (or MAM) is a fixed top limit the extra weight of the options has to be accommodated by reducing the payload capacity.

A second reason why calculating payloads can be difficult depends on the way they are measured. Some people like to measure and record the weight of each individual item, then add up all the results to produce the theoretical total. In practice this method rarely gives the true result because each time you measure an item its never quite perfect. Most weight measuring equipment produces it biggest errors when measuring small loads, so lots of small measures will produce a bigger error than one large load.

If you are towing, then the trailers nose weight has to be accommodated within the tugs payload. So if you have a payload of say 300Kg, and a nose weight of 75Kg then the payload capacity drops to 225Kg.

Essentially the ultimate test of a car weight is to actually measure it on a weighbridge, and fully loaded (with trailer attached)it must not exceed it MPM or either of its maximum axle loads.

 

[Lutz]

A number of items that the Prof has listed would be factory-fitted and should therefore already be included in the Mass in Service quoted in the V5c certificate. However, I would agree that no matter what the Mass in Service figure is, it would be risky to assume that it is definitive. After all, the data must have come from the car manufacturer in the first place and he does not normally document the actual weight of each car as it leaves the production line. Often the figure is a calculated one which doesn't allow for production tolerances, for example in sheet metal thickness, underbody protection, etc. In the case of my car, for example, the Mass in Service shown in the vehicle documentation states 2075 to 2115kg, i.e. a 40kg margin.

 

[Sproket]

High Tim,

Your question makes me wonder if you are trying to work out your payload (MPM-MIRO = payload).

Essentially the ultimate test of a car weight is to actually measure it on a weighbridge, and fully loaded (with trailer attached)it must not exceed it MPM or either of its maximum axle loads.

A few miles up the road from where i live there is a drive over axle weigh bridge.
I have used it quite a few times to work out what each axle is loaded to, as you drive over slowly it will show a reading for each axle front, back & van when you have the total weight.......
Disconnect the van & just weigh the car.....
You may be supprised with what you see........
Maybe you will be able to find one here in the Weighbridge Directory there are plenty up & down the country

 

[BigTim]

Thanks Lads
Sorry I did not get back to you but we left for the Continent on 23/07 and I did not get a chance to reply.
I was checking out the figures weights and payload for the car as I had bought a Reich Weight Control to check the weights of the car and caravan and wanted to make sure I was comparing with the correct weights.
Thanks again.
Tim