Relationship between axle weights and Gross Weight (1 Viewer)

Affiliate links here may earn MHF compensation

Solwaycruiser

Free Member
Feb 6, 2023
20
28
SW Scotland
Funster No
93,841
MH
Dethleffs
Exp
April 2022
Hi,
Going abroad soon so took MH to weighbridge just to check. My van is rated to 3650kg with front axle 1950kg and rear 2000kg (Dethleffs sticker). Two of us on board and full water and fuel, electric bikes and some loose clothes etc but some still to add. Weighed 3720kg gross and front 1740 and rear 1960. So okay on axles but not gross ( i did think it would be close). Not a problem as will drop out 80/ 90 litres of water. The van had an option from new to be rated at 3500kg or 3650kg and was already a stock order at 3650.
The van is 5 berth and 5 travel seats once loose cushions and seat conversion added. So if they were added and 5 people carried with clothes it would be way over by quite a bit. So my question is taking the axle weights can the gross weight of MH be further uprated as a paper exercise or is it more complicated than that. Did a search but couldn't see an answer. We bought new last year so no changes made by anyone to the original spec. TIA
 
Jun 16, 2017
337
613
Bridlington
Funster No
49,041
MH
Pilote P650GJ
Exp
Happy to help
It’s usually a paper exercise to get to the combined axle weights. In your case 3850kg. I’ve done it twice without having to upgrade anything.
 
Upvote 0
Jul 6, 2009
1,860
2,325
Funster No
7,383
To get 2240 kg over the rear axle if you are on 15” wheels they will need to be 225/70/R15 on our Aspire to go from 3650 to 3850 took semi air and from 215 to 225 tyres (2012 Boxer chassis)

Subscribers  do not see these advertisements

 
Upvote 0

Lenny HB

LIFE MEMBER
Oct 18, 2007
54,391
154,349
On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
Yep, should be able to go to 3950kg without mods but I querie your front axle at 1950 is unusual are you sure it's not 1850 which would allow a max of 3850kg.
 
Upvote 0

Minxy

LIFE MEMBER
Aug 22, 2007
32,773
66,954
E Yorks
Funster No
149
MH
Carthago Compactline
Exp
Since 1996, had Elddis/Swift/Rapido/Rimor/Chausson MHs. Autocruise/Globecar PVCs/Compactline i-138
It could be that as part of the 3650kg chassis uprate the front springs were changed to be able to take extra capacity but that would be extremely unusual, my bet is on an error when the sticker was produced and it should be 1850kg on the front.
 
Upvote 0
OP
OP
S

Solwaycruiser

Free Member
Feb 6, 2023
20
28
SW Scotland
Funster No
93,841
MH
Dethleffs
Exp
April 2022
What does the base vehicle plate say?
Just looked at the Ducato chassis plate and it says 3650 gross, front 1960 and rear 2000. So presumably Dethleffs downgrade to 3500 for those that do not have the licence for over that weight but won't/ can't exceed the Ducato plate for the higher plating ?
Oh and looked for a Certificate of Conformaty but haven't found it so far.
 
Upvote 0

Hoovie

Free Member
May 16, 2021
1,249
1,689
Funster No
81,251
MH
Autotrail
It’s usually a paper exercise to get to the combined axle weights. In your case 3850kg. I’ve done it twice without having to upgrade anything.
I know people do that, and some companies will issue revised plates on that basis, but I find it a very dubious practice.
If you have a GVW which is an exact addition of the axles, you have to be 100% perfectly balanced front to rear to run upto the GVW legally. Anyone who achieves will be by pure luck.
There is a reason why the combined axle weights are more than the GVW, and it is not so someone can increase the GVW by writing in a bigger number and nothing else.
I think it is pretty irresponsible actually, and the companies who actually for money issue revised plates and paperwork on this basis are performing a poor service IMO.

People say SVTech are too expensive, but one difference between them and other companies who are cheaper is that SVTech won't just issue a update on the basis of x+y=z. When I did my weight uprate, I found I could actually get a plate giving me 3850Kg with no changes based on axle weights. But SVTech would only issue a plate to 3700Kg (could have been 3600Kg?) with no changes and to go to 3850Kg, the rear suspension would need to be adjusted to give a higher weight. They don't make this daft assumption that people will load their vans perfectly (who says that is even possible with some layouts and designs?).
I went with SVTech even though they were more expensive than other options as their approach pretty well mirrored my own thoughts and - IMO - have a much more engineering-minded approach and rational to uprating.

Anyway, that is my own opinion. Others may have their own but to anyone who uprates to the combined axle weights to make a new GVW .... go to a weighbridge once you have loaded up ready for your trip and check you are within the limits of ALL THREE factors - gross vehicle weight, front axle AND rear axle. I will guarantee that if you are at the GVW limit, you will be over on one of the axles.
 
Upvote 0

Minxy

LIFE MEMBER
Aug 22, 2007
32,773
66,954
E Yorks
Funster No
149
MH
Carthago Compactline
Exp
Since 1996, had Elddis/Swift/Rapido/Rimor/Chausson MHs. Autocruise/Globecar PVCs/Compactline i-138
I know people do that, and some companies will issue revised plates on that basis, but I find it a very dubious practice.
If you have a GVW which is an exact addition of the axles, you have to be 100% perfectly balanced front to rear to run upto the GVW legally. Anyone who achieves will be by pure luck.
There is a reason why the combined axle weights are more than the GVW, and it is not so someone can increase the GVW by writing in a bigger number and nothing else.
I think it is pretty irresponsible actually, and the companies who actually for money issue revised plates and paperwork on this basis are performing a poor service IMO.

People say SVTech are too expensive, but one difference between them and other companies who are cheaper is that SVTech won't just issue a update on the basis of x+y=z. When I did my weight uprate, I found I could actually get a plate giving me 3850Kg with no changes based on axle weights. But SVTech would only issue a plate to 3700Kg (could have been 3600Kg?) with no changes and to go to 3850Kg, the rear suspension would need to be adjusted to give a higher weight. They don't make this daft assumption that people will load their vans perfectly (who says that is even possible with some layouts and designs?).
I went with SVTech even though they were more expensive than other options as their approach pretty well mirrored my own thoughts and - IMO - have a much more engineering-minded approach and rational to uprating.

Anyway, that is my own opinion. Others may have their own but to anyone who uprates to the combined axle weights to make a new GVW .... go to a weighbridge once you have loaded up ready for your trip and check you are within the limits of ALL THREE factors - gross vehicle weight, front axle AND rear axle. I will guarantee that if you are at the GVW limit, you will be over on one of the axles.
I understand your thinking but going up to the max isn't against the law and the vehicle can run at that safely. SVTech are restricting the max for the numpties who don't ensure that they are loaded correctly and as such those numpties could still be way over on the rear axle even within the 3700kg weight.

You went with them for your own reasons but there was nothing wrong with going with VE at half the cost and asking them to restrict you to 3700kg. If I was in the market for a MH though the identical one plated at 3850kg would get my vote over one at 3700kg.
 
Upvote 1

Hoovie

Free Member
May 16, 2021
1,249
1,689
Funster No
81,251
MH
Autotrail
I understand your thinking but going up to the max isn't against the law and the vehicle can run at that safely. SVTech are restricting the max for the numpties who don't ensure that they are loaded correctly and as such those numpties could still be way over on the rear axle even within the 3700kg weight.

You went with them for your own reasons but there was nothing wrong with going with VE at half the cost and asking them to restrict you to 3700kg. If I was in the market for a MH though the identical one plated at 3850kg would get my vote over one at 3700kg.
Didn't say it was illegal, I said it was irresponsible (or words to that effect).
Could have gone to 3700Kg. Except I wanted to go to 3850kg.
And you say "those numpties".... You reckon you could set up your weight distribution right to a single kilo? Really?

Subscribers  do not see these advertisements

 
Upvote 0
May 7, 2016
7,446
12,174
West Sussex
Funster No
42,951
MH
Malibu Van 640 LE K
Exp
Since 2003
Didn't say it was illegal, I said it was irresponsible (or words to that effect).
Could have gone to 3700Kg. Except I wanted to go to 3850kg.
And you say "those numpties".... You reckon you could set up your weight distribution right to a single kilo? Really?
Even with some flexibility between axle weights and gross weight it would be easy enough to overload the rear axle, many do. Lots of motorhomes are sold new with the axle weights adding up to the gross weight. I can’t see it makes any difference, you still have to get it weighed to know what capacity you have available on each axle.
 
Upvote 0

TheBig1

LIFE MEMBER
Nov 27, 2011
17,680
43,697
Dorset
Funster No
19,048
MH
A class
Exp
many many years! since I was a kid
Running down other businesses that provide the engineers letter ignores the fact that, that letter must be signed off by a qualified engineer, with calculations available should the need arise. Those calculations are not based on a theoretical set of weights, but those supplied by the manufacturer as the vehicle left the factory. The chassis and suspension are generally capable of a much higher loading but a margin of safe measure is included. 3850kg is the theoretical maximum within the safety margin without upgrading tyres and/or suspension to increase to 4250kg. Above that would require the heavy duty chassis as an option from the factory

SVtech were the only player in the game for several years, offering services to private customers. Having been involved previously with converting a lorry, by extending it to create a recovery vehicle, I know of other engineers that specialise in weight upgrades, but they only deal commercially with other engineers. There have since been a few engineers that did start helping Motorhomers, specifically the late John Russel and Vehicle Engineering. Both of those have qualified engineers and they would never just accept the figures supplied by the customer. They have access to the necessary data to calculate the safe weight
 
Upvote 0

Hoovie

Free Member
May 16, 2021
1,249
1,689
Funster No
81,251
MH
Autotrail
Running down other businesses that provide the engineers letter ignores the fact that, that letter must be signed off by a qualified engineer, with calculations available should the need arise. Those calculations are not based on a theoretical set of weights, but those supplied by the manufacturer as the vehicle left the factory. The chassis and suspension are generally capable of a much higher loading but a margin of safe measure is included. 3850kg is the theoretical maximum within the safety margin without upgrading tyres and/or suspension to increase to 4250kg. Above that would require the heavy duty chassis as an option from the factory

SVtech were the only player in the game for several years, offering services to private customers. Having been involved previously with converting a lorry, by extending it to create a recovery vehicle, I know of other engineers that specialise in weight upgrades, but they only deal commercially with other engineers. There have since been a few engineers that did start helping Motorhomers, specifically the late John Russel and Vehicle Engineering. Both of those have qualified engineers and they would never just accept the figures supplied by the customer. They have access to the necessary data to calculate the safe weight
What is being ignored is the quoted axle ratings and reality. Nothing to do with numbers from a customer but talking about the numbers clearly specified on the VIN plate. I have no doubt there are safety margins built in to the numbers quoted by the factory but that is irrelevant to the point.
By having a GVW which depends on a perfect weight distribution means that if the GVW is used fully, the chance of an axle being over the specified limit is virtually guaranteed. Saying that is fine because there are safety margins inherently in the design is like saying it is ok to go 30MPH above the speed because the brakes work well. Try using that excuse to get a ticket cancelled. Doesn't make it any more legal than running an axle over its specified weight limit.
If vans got checked and weight limits were actually enforced, there would be a lot more people who would be disappointed with the results of these uprates, getting fined even though they were within the GVW.
The problem is people don't care about actually running their vehicles legally. I wonder how many people even get their vans weighed to check what they are running at to start with? (FWIW, every van I have had I have had weighed multiple times to check the overall and the axle weights).
 
Upvote 0

Minxy

LIFE MEMBER
Aug 22, 2007
32,773
66,954
E Yorks
Funster No
149
MH
Carthago Compactline
Exp
Since 1996, had Elddis/Swift/Rapido/Rimor/Chausson MHs. Autocruise/Globecar PVCs/Compactline i-138
Didn't say it was illegal, I said it was irresponsible (or words to that effect).
I know, but it's legal so that's what matters if you get stopped by the plod. The limits have been set by those who know what they're doing (ie qualified engineers) and regardless of whether you think it's irresponsible or not, it's their professional expertise I'll take notice of.

Could have gone to 3700Kg. Except I wanted to go to 3850kg.
So are you at 3850kg or 3700kg? I'm loosing track of what you ended up with ... I assume 3700kg as you used SVTech.

The only person who's got an issue seems to be you, for some reason you wanted to pay more for the same service, you stuck by 'your principles' and that's your prerogative but why you would do that especially since it makes no difference to anyone else is beyond me.

And you say "those numpties"....
To me a numpty is anyone who doesn't check their overall and individual axle weights.

You reckon you could set up your weight distribution right to a single kilo? Really?
I never claimed I could but if I needed to I would however it would be difficult to load up the front axle to it's max as there's simply nowhere up that end to store stuff to be able to do so - I'd never buy a MH with such a tight payload in the first place though.
 
Upvote 0
Jun 12, 2020
480
1,416
Scotland
Funster No
71,681
MH
Carthago 138 Compact
Exp
Since 2017
Yep, should be able to go to 3950kg without mods but I querie your front axle at 1950 is unusual are you sure it's not 1850 which would allow a max of 3850kg.
My Compactline 138 has factory fitted uprated front shockers apparently ( possibly due to 9 speed auto and it's extra weight????).
1950 kg max. OP may have the same Lenny.

Subscribers  do not see these advertisements

 
Upvote 0

Hoovie

Free Member
May 16, 2021
1,249
1,689
Funster No
81,251
MH
Autotrail
I know, but it's legal so that's what matters if you get stopped by the plod. The limits have been set by those who know what they're doing (ie qualified engineers) and regardless of whether you think it's irresponsible or not, it's their professional expertise I'll take notice of.


So are you at 3850kg or 3700kg? I'm loosing track of what you ended up with ... I assume 3700kg as you used SVTech.
You know what "assume" means ;)
I said SVTech would not issue a update above 3700Kg without making changes. I did not say if I went above 3700 (and made changes) or or not. Yes, I made changes to uprate the load capacity of the rear axle so I could go to 3850 AND have load distribution flexibility.
The only person who's got an issue seems to be you, for some reason you wanted to pay more for the same service, you stuck by 'your principles' and that's your prerogative but why you would do that especially since it makes no difference to anyone else is beyond me.
Not the same service.
To me a numpty is anyone who doesn't check their overall and individual axle weights.


I never claimed I could but if I needed to I would however it would be difficult to load up the front axle to it's max as there's simply nowhere up that end to store stuff to be able to do so - I'd never buy a MH with such a tight payload in the first place though.
So there you go. You could not load up the front axle to its max. And I am sure others with a similar van would be in the same position. But you are fine with a vehicle having a GVW that relies on BOTH axles being fully utilized.
Maybe YOU would not buy a MH with such a tight payload, but others do, and exceed it - sometimes knowingly and sometimes not. And sometimes they think they are doing the right thing by getting an uprate but they are not, and being charged money for no good result if they get stopped and weight-checked.
 
Upvote 0
Jun 16, 2017
337
613
Bridlington
Funster No
49,041
MH
Pilote P650GJ
Exp
Happy to help
You know what "assume" means ;)
I said SVTech would not issue a update above 3700Kg without making changes. I did not say if I went above 3700 (and made changes) or or not. Yes, I made changes to uprate the load capacity of the rear axle so I could go to 3850 AND have load distribution flexibility.

Not the same service.

So there you go. You could not load up the front axle to its max. And I am sure others with a similar van would be in the same position. But you are fine with a vehicle having a GVW that relies on BOTH axles being fully utilized.
Maybe YOU would not buy a MH with such a tight payload, but others do, and exceed it - sometimes knowingly and sometimes not. And sometimes they think they are doing the right thing by getting an uprate but they are not, and being charged money for no good result if they get stopped and weight-checked.
Oh dear you have got a bee in your bonnet about this. The OP a will be fine on the weights he posted going to 3850, he is wise enough to realise he needs to increase his gvw to stay legal.
I agree it’s difficult to get the front axle to the allowed weight and all too easy to overload the rear.
The truth of the matter is that many will be overweight, you assume that motorhome owners are not as wise as you regarding this issue however it is their responsibility to have the van weighed.
My van and my responsibility to ensure it’s safely loaded.
 
Upvote 0

Minxy

LIFE MEMBER
Aug 22, 2007
32,773
66,954
E Yorks
Funster No
149
MH
Carthago Compactline
Exp
Since 1996, had Elddis/Swift/Rapido/Rimor/Chausson MHs. Autocruise/Globecar PVCs/Compactline i-138
Oh dear you have got a bee in your bonnet about this.
More a wasp in his whoopee cap! :LOL:

1679839812567.png


I just so love it when someone tries to teach me to suck eggs ... what he doesn't know is that it was me who did a lot of research into this and found the first 'alternative company' to SVTech which saved funsters a load of dosh! :giggle:
 
Upvote 0

Hoovie

Free Member
May 16, 2021
1,249
1,689
Funster No
81,251
MH
Autotrail
More a wasp in his whoopee cap! :LOL:

View attachment 731780

I just so love it when someone tries to teach me to suck eggs ... what he doesn't know is that it was me who did a lot of research into this and found the first 'alternative company' to SVTech which saved funsters a load of dosh! :giggle:
Good for you. Give yourself a little pat on the back for being such a clever girl :D
Actually what you don't know is I already knew about that company, who came into the picture a little while after John Russell passed away (if I recall correctly, the company you 'found' was started by someone who found the gap in the market post-Russell?).
But I don't like their approach any more then I did with the previous companies (and why I didn't use them either). But not a problem, each to their own, but I still don't like that approach for all the reasons previously given.

Subscribers  do not see these advertisements

 
Upvote 0

Hoovie

Free Member
May 16, 2021
1,249
1,689
Funster No
81,251
MH
Autotrail
Oh dear you have got a bee in your bonnet about this. The OP a will be fine on the weights he posted going to 3850, he is wise enough to realise he needs to increase his gvw to stay legal.
I agree it’s difficult to get the front axle to the allowed weight and all too easy to overload the rear.
The truth of the matter is that many will be overweight, you assume that motorhome owners are not as wise as you regarding this issue however it is their responsibility to have the van weighed.
My van and my responsibility to ensure it’s safely loaded.
no bee in my bonnet. Just think it is good for people to realise the limitations and 'gotchas' of making the GVW add up to precisely the axle weight combination.
I also don't assume MH owners are not as wise as me regarding this issue. Maybe just a matter of them assuming they are being given a USABLE uprate and not just a mathematical one when paying for an uprate service?
 
Upvote 0

Minxy

LIFE MEMBER
Aug 22, 2007
32,773
66,954
E Yorks
Funster No
149
MH
Carthago Compactline
Exp
Since 1996, had Elddis/Swift/Rapido/Rimor/Chausson MHs. Autocruise/Globecar PVCs/Compactline i-138
I said SVTech would not issue a update above 3700Kg without making changes. I did not say if I went above 3700 (and made changes) or or not. Yes, I made changes to uprate the load capacity of the rear axle so I could go to 3850 AND have load distribution flexibility.
So I assume you got semi-air fitted in order to go to 3850kg, did you get an increase in your rear axle capacity too?

I'll tell you why I find this so interesting ... SVTech told us we could have our Carthago uprated from 3500kg (1850kg front, 2000kg rear) to 3850kg with no modification at all just utilising the existing axle capacities to their max, they would quite happily have done this. It was only because we also wanted to increase the capacity of the rear axle to 2240kg that we had semi-air put on (cost £2,000), if we hadn't wanted to do this we could've saved quite a bit of dosh but didn't want the risk of being overloaded on the rear end (150L water tank, 100L waste tank (although never more than half full) plus all the kit in the large garage would've taken us too close for our liking).

We now have a front axle of 1850kg and rear of 2240kg but a MAM of 3850kg rather than a combined 4090kg as we weren't bothered about going increasing to that as we'd never be able to load the front up anywhere near its existing maximum, however we were told we could fit stronger springs and then could fully utilise 4090kg.

So, how could they tell us we could go to 3850kg with NO mods and utilise the maximum capacity of both axles but they told you that you couldn't? There are others on the forum who've had conflicting info from SVTech, some told to fit semi-air, some not, just to go to the max of their existing axles, ie 3850kg.

As they can't seem to make their minds up this for me makes them less 'professional' than VWE.


Not the same service.
No, thank goodness ... it's just an unnecessary expense for some when the axles are already capable of carrying the capacity up to the combined maximum.
 
Upvote 0
Jul 26, 2018
635
2,532
Funster No
55,161
Didn't say it was illegal, I said it was irresponsible (or words to that effect).
Could have gone to 3700Kg. Except I wanted to go to 3850kg.
And you say "those numpties".... You reckon you could set up your weight distribution right to a single kilo? Really?
Can you go to 3850kg, the weight you chose, and be accurate to the exact kilo?

Regardless of what weight is depicted for individual axles, you chose a gross weight (on my assumption) that this was the weight required by you and allowable by the manufacturer. I don’t really understand you’re argument that seems to be that by choosing a gross weight can’t be right based on the fact that each axle can legally be loaded to its maximum limit. Regardless of what weight is listed on the weight plate at some point you have the same conclusion where breaching the limit on any axle or total weight will be illegal. Yet even a lower weight for the same vehicle whether on axles or weight would still leave you in the same position, just with different weights. As long as the axle or total weight is within manufacturer specification I really don’t see what the direction of your argument is?
 
Upvote 0

Minxy

LIFE MEMBER
Aug 22, 2007
32,773
66,954
E Yorks
Funster No
149
MH
Carthago Compactline
Exp
Since 1996, had Elddis/Swift/Rapido/Rimor/Chausson MHs. Autocruise/Globecar PVCs/Compactline i-138
Good for you. Give yourself a little pat on the back for being such a clever girl :D
Yes I was wasn't I! :giggle:
Actually what you don't know is I already knew about that company, who came into the picture a little while after John Russell passed away (if I recall correctly, the company you 'found' was started by someone who found the gap in the market post-Russell?).
Silly boy ;) ... you're not as well versed as you think ... what you don't know is ... it was I (Le Clerc! :giggle:) who found out about John Russell's company as he'd only just been approved by DVSA/DVLA as being qualified to do the weight confirmations. I spent a long time ringing round various companies to see who could do it to no avail, he was the ONLY alternative to SVTech ... in fact I was his first MH customer. :dance2: The subsequent company obviously spotted the need for an alternative to SVTech once John passed away (lovely chap he was).
 
Upvote 0

Hoovie

Free Member
May 16, 2021
1,249
1,689
Funster No
81,251
MH
Autotrail
Yes I was wasn't I! :giggle:

Silly boy ;) ... you're not as well versed as you think ... what you don't know is ... it was I (Le Clerc! :giggle:) who found out about John Russell's company as he'd only just been approved by DVSA/DVLA as being qualified to do the weight confirmations. I spent a long time ringing round various companies to see who could do it to no avail, he was the ONLY alternative to SVTech ... in fact I was his first MH customer. :dance2: The subsequent company obviously spotted the need for an alternative to SVTech once John passed away (lovely chap he was).
You are just agreeing with me basically.
Well done again, you clever old thing. You revealed all to the world of Motorhome Fun :D (PS. there are other places on the internet with info, you know ;) )
 
Upvote 0

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Log in

Already a member? Log in here.

Latest journal entries

Funsters who are viewing this thread

Back
Top