Kerbweight accuracy - A warning!

[Ste6t9]

Hi all.

You will probably know that I took up a lot of your valuable time last month asking for lots of advice and going through lots of weighbridge trips over the past month and I thought I would put my thoughts here to maybe help people in the future who may be panicking unnecessarily.

The issue of kerbweight in relation to our car has baffled me since we got it. We have a Mitsubishi Outlander 2.2 Di-D 4. On first getting the car from almost new (and having a towbar fitted by Mitsubishi) I was under the impression it would pretty much tow anything.

That is until I started shopping round for caravans and the towsure?!? matching software kept quoting the car as having a kerbweight of just 1685kg.

This ultimately influenced our choice of van and to be fair, it towed like a dream up hill and down dale.

As you may know, we are upgrading and therefore was at the point of having to maybe change car. Mitsubishi were less than helpful and everywhere I looked, the kerbweight pointed to 1685kg with a driver or 1610kg without. Now if you know what an Outlander looks like, it's not small, on a par with the Nissan X-Trail. So I eventually took it in as near to factory conditions (with a full tank) as I could get it and ran it over our local weighbridge (being used by the DVSA at the time - so pretty accurate) and it weighed off at 1860kg.

Therefore I clearly weigh 250kg or 39 stone!!!!!

(Now lockdown hasn't been kind but I'm quite sure I'm not that heavy)

So basically this is here as a reminder that your kerbweights might not be as accurate as your paperwork or even your car manufacturer may say. I was ucky in that the car is WAY heavier than published but could an error happen the other way? - this could result in some dangerous outfits on the road.

I wonder if anyone else out there has found any massive differences or is it just an error or oversight by Mitsubishi? Or am I just manically obsessed by it now???

In hindsight, I shoudl have known something was wrong when the matching software showed our previous smaller car (Kia Sportage to have 150kg more kerbweight)

 

[Lutz]

The trouble is that many sources quote a figure which they call kerbweight, but what is in actual fact mass in service/mass in running order. This is because kerbweight is not documented anywhere, but mass in service/mass in running order is and besides, kerbweight is specific to each and every vehicle, so it only makes sense to quote kerbweight when linked to a particular chassis number.
Mass in service/mass in running order on the other hand is not specific to the vehicle in question. It is only the weight of the vehicle that the manufacturer submitted for type approval and that may have had a slightly different specification. That explains why there can be quite substantial differences between kerbweight and published data based on mass in service/mass in running order. Luckily, kerbweight is almost invariably greater than mass in service/mass in running order.

 

[Hutch]

Ste6t9, I don't think you were being over cautious, It was the correct think to do all the weighing, but just think about how much weight you could have put in your tug, believing it to be the 1685 kg figure. You could have put an extra 175 kg in it and be over weight. Therefore over loading your max train weight by 175 kg.

 

[Ste6t9]

Absolutely. Hence why the night before we went to Switzerland with it, I took it to the weighbridge (I’m lucky it’s only 20 minutes away and 24h availability) I do remember thinking it came out heavier than expected but still well under the train weight of 4390!!

 

[Hutch]

I hope you had a nice stay over there, I used to visit friends who lived at the end of lake Zurich, I thought it was wonderfull scenery, but incredably expencieve. We used to *** into Germany once or twice a week to buy meat and cheese.

 

[Ste6t9]

I hope you had a nice stay over there, I used to visit friends who lived at the end of lake Zurich, I thought it was wonderfull scenery, but incredably expencieve. We used to *** into Germany once or twice a week to buy meat and cheese.

loved it. We did a week in Holland then a 1 night stay in Luxembourg then onto a week in Interlaken. Absolutely amazing and a great experience towing all the way there!!!

 

[ProfJohnL]

Ste6t9, I don't think you were being over cautious, It was the correct think to do all the weighing, but just think about how much weight you could have put in your tug, believing it to be the 1685 kg figure. You could have put an extra 175 kg in it and be over weight. Therefore over loading your max train weight by 175 kg.

This is why the GVW GTW Front Axle and read axle (In other words the weight plate on the vehicle ) are the final arbiters in these matters.

 

[Hutch]

This is why the GVW GTW Front Axle and read axle (In other words the weight plate on the vehicle ) are the final arbiters in these matters.

Prof, It makes no difference, if the kerb weight you are given , is not correct.
In "The Books" Ste could have been 175 kg over their limit.
When pulled over, by the authoritietys, and he states I weighed my payload, it was XXX kg, and it was over, he/she is in the wrong.
Whom is to be blamed.

 

[Hutch]

I can see a lot of caravaners an trailer folk being well over their limits.

 

[Lutz]

To rely on any kerbweight figure out of a brochure, database, or any publication for that matter is self-deceptive to say the least. It can never be more than a rough guide. There is no way round weighing the vehicle empty if you want or need an accurate figure because you're close to the limit to start with.

 

[Ste6t9]

To rely on any kerbweight figure out of a brochure, database, or any publication for that matter is self-deceptive to say the least. It can never be more than a rough guide. There is no way round weighing the vehicle empty if you want or need an accurate figure because you're close to the limit to start with.

Agreed I’m sure no car is spot on but I’m only posting this as a pointer and to express my disbelief at being nearly a quarter of a ton out.

 

[Hutch]

To rely on any kerbweight figure out of a brochure, database, or any publication for that matter is self-deceptive to say the least. It can never be more than a rough guide. There is no way round weighing the vehicle empty if you want or need an accurate figure because you're close to the limit to start with.

Lutz, you are correct and the many of us that tow regulary will take regard to their weights,
But a lot of new comers will be unaware of the restrictions, and we can hope by our information , we can help them to keep safe and within he laws.

 

[ProfJohnL]

Prof, It makes no difference, if the kerb weight you are given , is not correct.
In "The Books" Ste could have been 175 kg over their limit.
When pulled over, by the authoritietys, and he states I weighed my payload, it was XXX kg, and it was over, he/she is in the wrong.
Whom is to be blamed.

The driver of the vehicle is to blame. The arbiter is the GVW or GTW and axle limits. Weighing your payload does not cut the mustard as an excuse, as you then have to know teh vehicle unladen weight. in the end its if the vehicle exceeds any of the limits on its plates.

It doesn't have to be just new drivers that need to be aware of the limits its every driver and you should know your vehicle does not exceed the limits and the only way you can be sure of that is to weigh it .

Ignorance is not a get out of jail ticket.

Anyone taking up an activity that will put extra load on or in your vehicle should research what is allowed and take steps to verify your vehicle complies.

 

[Ste6t9]

The driver of the vehicle is to blame. The arbiter is the GVW or GTW and axle limits. Weighing your payload does not cut the mustard as an excuse, as you then have to know teh vehicle unladen weight. in the end its if the vehicle exceeds any of the limits on its plates.

It doesn't have to be just new drivers that need to be aware of the limits its every driver and you should know your vehicle does not exceed the limits and the only way you can be sure of that is to weigh it .

Ignorance is not a get out of jail ticket.

Anyone taking up an activity that will put extra load on or in your vehicle should research what is allowed and take steps to verify your vehicle complies.

yes John. So this is why I’m glad I weighed the car as close to kerbweight “standard” as I could. Turns out I can tow a heavier van safely and know how much I can put in the car safely.

Now I have figures I can work from.

I will also be weighing the entire outfit direct from the dealers in the same fashion on the day I collect it.

 

[Hutch]

Prof, get Real. Not everyone will take there car to a weigh bridge, they will take a written figure from a website, or there V 5. . Not a weigh bridge,
Thats all I am saying, I am trying to help newcomers.

 

[Ste6t9]

Prof, get Real. Not everyone will take there car to a weigh bridge, they will take a written figure from a website, or there V 5. . Not a weigh bridge,
Thats all I am saying, I am trying to help newcomers.

Sadly, this is true therefore I hope most published kerbweights are more accurate than mine.

 

[Hutch]

Sadly, this is true therefore I hope most published kerbweights are more accurate than mine.

What Ste6t9, has written in the forum has I think helped many newcomers and many others, rather than confuse folk , as often others do. So I give him a big thanks to his Threads.

 

[ProfJohnL]

Prof, get Real. Not everyone will take there car to a weigh bridge, they will take a written figure from a website, or there V 5. . Not a weigh bridge,
Thats all I am saying, I am trying to help newcomers.

But that is exactly what they should not do. If they are stopped and as in the case you have suggested were 175kg over the GTW then I suspect with such an overload there would likely be prosecutions in post.

It doesn't matter what the manufactures say their unloaded weights are (Car or caravan)and the authorities won't care about what the kerbweight is claimed to be, their criteria is if any of the vehicles specified maximum limits are exceeded. That is the "REAL" situation.

Don't waste time and effort trying to empty a car or caravan to find its kerb weight , it makes more sense to start at the top and work backwards.

For example Load your car and caravan as if your going on holiday and get it weighed. You will know then if an how much over or under weight you are compared to the stated limits

Get home and unload every item and weight it and add it to a spreadsheet. when their empty, you can you know how much load you had in the outfit.

Subtract the manifest load from the actual total weights, and you have the unladen weights.

 

[Lutz]

Kerbweight is not a value which is documented anywhere so there is no way one can fall back on it as an arbitrator or as a reliable basis with which one can work.

 

[JezzerB]

And it isn't something I worry about-or have ever measured-rated tow capacity of the car is legally the defining factor and what I take car to obey.

 

[Stagn8]

Just had my Outlander MOT’d at Halfords and they gave me the brake performance sheet which includes overall weight plus individual axle weights. They confirmed what I had already been told by Mitsubishi that it weighs 1860 kilo. Not sure that this true of all MOT stations but I believe they all have to weigh the vehicle to get the correct brake performance percentages.

 

[Ste6t9]

Just had my Outlander MOT’d at Halfords and they gave me the brake performance sheet which includes overall weight plus individual axle weights. They confirmed what I had already been told by Mitsubishi that it weighs 1860 kilo. Not sure that this true of all MOT stations but I believe they all have to weigh the vehicle to get the correct brake performance percentages.

Thanks for this. Just confirms what I have been thinking all along.

 

[otherclive]

Just had my Outlander MOT’d at Halfords and they gave me the brake performance sheet which includes overall weight plus individual axle weights. They confirmed what I had already been told by Mitsubishi that it weighs 1860 kilo. Not sure that this true of all MOT stations but I believe they all have to weigh the vehicle to get the correct brake performance percentages.

Never had a weight reading provided by an MOT Center but thank you for the info.

 

[RogerL]

Just had my Outlander MOT’d at Halfords and they gave me the brake performance sheet which includes overall weight plus individual axle weights. They confirmed what I had already been told by Mitsubishi that it weighs 1860 kilo. Not sure that this true of all MOT stations but I believe they all have to weigh the vehicle to get the correct brake performance percentages.

Few MoT stations have the ability to weigh a vehicle - they use database figures to set the rolling road brake tester.

 

[Buckman]

Few MoT stations have the ability to weigh a vehicle - they use database figures to set the rolling road brake tester.

If you have an AWD vehicle they may not be able to do the brake test correctly on the rollers.