Revenue weight puzzle

[Keithl]

Hi Terry,

 

I'll try to answer some of your questions as best I can!

 

If your tyres really are only 100N rated then you will almost certainly need new tyres, at least on the rear! I have the same size but 112 rated.

 

Are you absolutely certain that all four tyres are the same rating?

 

100N are rated to 800 kg per tyre or 1,600 kg per axle, you need 112 rated to give you 1,120 kg per tyre or 2,240 kg per axle.

 

IMO the tyres are unsuitable in the first place!!!

 

Weights:

 

Our full width rear bumper/tow hitch weighs 50 kg so yours could easily be 60 kg.

 

The second weight on your VIN plates are Gross Train Weights, ie including a trailer. It appears that Rimor have down rated the towing capacity, most likely due the the extended rear chassis.

 

And finally it is usual for the two axle weight limits to total more than the GVW. This is to allow a tolerance for loading, ie not having to move load back and fore to balance individual axle weights. SV Tech take advantage of this 'spare' capacity to uprate your GVW. Just be careful not to overload one axle or the other.

 

Keith.

[Derek Uzzell]

Terry

 

The format of a motorhome’s ‘chassis-plate’ (or chassis-plates) has a reasonable degree of standardisation where the weight-related data are concerned.

 

I’ve attached an image of the chassis-plate of a Ford vehicle that has two axles (one front and one rear). This plate shows the vehicle’s maximum authorised weights for (in descending order) the Gross Vehicle Weight (GVW), the Gross Train Weight (GTW), the Front Axle maximum weight and the Rear Axle maximum weight.

 

The ‘chassis-plate’ is often called the “VIN-plate”. The GVW can also be referred to as the MAM (Maximum Authorised Mass) or the MTPLM (Maximum Technically Permissible Laden Mass). The GTW can also be called the GCW (Gross Combination Weight).

 

https://www.gov.uk/government/publications/towing-a-trailer-with-a-car-or-van/towing-a-trailer-with-a-car-or-van-the-basics

 

As Keith says, it’s normal for the total of the front-axle and rear-axle weights to exceed the GVW. This will be evident from the Ford chassis-plate (GVW = 2640kg; Axle weight total 1350kg + 1550kg = 2900kg).

 

I happen to have a 2004 Michelin Van Tyre technical handbook and this advises that - for February 2000-onwards Mercedes Sprinter 316CDi vehicles - the appropriate Michelin tyres then would have been “Agilis 81” pattern with a 225/70 R15C 112R specification with inflation pressures of 44psi (front axle) and 65psi (rear axle).

 

The specification of tyres suitable for your motorhome needs to include a “C” and (as Keith says) have a Load Rating of at least 112 to handle its 2240kg rear-axle load-carrying capability. So you need 225/70 R15C 112) tyres.

 

https://www.blackcircles.com/helpcentre/tyres/what-is-load-rating

 

I notice that 225/70 R15 100 tyres are marketed, but these don’t appear to carry the “C” marking and will be intended for large pick-ups or 4x4s. It would help to know the make/name of the tyres on your motorhome for (as Keith warns) if they are not “C”-marked and genuinely have a Load Rating of 100, they are definitely unsuitable and potentially dangerous.

 

It is possible for a motorhome owner to DIY the process of having his/her vehicle’s weights altered upwards or downwards, though dealing with the DVLA about this may prove laborious.

 

SVTech and JR Consultants, who both tend to be used by motorcaravanners to middle-manage the weight-uprating procedure, are just ‘facilitators’ that for a fee will provide the paperwork that is required for the exercise and that the DVLA will consider acceptable - but neither company can legally authorise the weight alteration.

 

If a motorhome’s GVW is to be altered, the following will be required.

 

1. The DVLA must issue a new V5C document that shows the revised GVW and the motorhome’s owner must receive and check that document’s correctness.

 

2. Logically, the motorhome should carry an indicator showing the revised GVW, and SVTech address this by sending the motorhome’s owner a new VIN-plate together with the paperwork that the owner will submit to the DVLA.

 

It stands to reason that the new VIN-plate has no legal ’power’

 

- until the DVLA has received the paperwork sent to them by the motorhome’s owner

 

- until the DVLA has agreed that the GVW revision is acceptable and produced a new V5C

 

- until the owner has received the new V5C and checked that it is correct.

 

Until the above things have happened the data on the motorhome’s original VIN-plate continues to be in force: after that the GVW change will have been completed and the original VIN-plate’s data are now superseded by the revised values on the new VIN-plate. Any suggestion that attaching to a motorhome a VIN-plate with a revised GVW ‘legalises’ the weight-change without completion of the three stages I’ve just mentioned having taken place is nonsence.

 

It’s evident from on-line entries that a Mercedes Sprinter can have a Gross Train Weight of 6300kg, but it is the GTW figure on each individual Sprinter’s VIN-plate that ‘counts’. As the Kentucky Camp’s VIN-plate has a 4350kg GTW datum, that’s the motorhome’s GTW and the 6300kg figure on the driver’s seat’s side is irrelevant. It’s quite common for coachbuilt motorhomes to have a significantly lower towing capacity compared to the ‘commercial vehicle’ equivalent and (as Keith suggests) it’s probable that Rimor has reduced the Estro 8’s GTW well down to match its construction limitations.

[CaptSteve]

Keithl - 2019-06-28 4:32 PM

 

CaptSteve - 2019-06-28 1:59 PM

 

 

I can add some information having gone through something similar and only finally finished the last step yesterday.

 

I also bought my van in a bit of a rush, and didn’t pay enough attention at the handover.

 

It had a plate showing 3,500kg and I set off to weight it with me, half a tank of fuel and a few essentials. The figures showed that I would be overweight with fresh water, gas and the family.

 

After some advice from the guys on here, and finding other vehicles like mine on the internet with a 4050kg plate, I spoke to the DVLA to see how to change my weight. They wanted a COC/letter from the manufacturer or specialist showing that the vehicle had been modified to carry the extra weight. Through the dealership I bought the vehicle, we contacted Hymer. They were able to issue a new weight, 4050kg, without any modification to the van (it’s the same as yours Merc 316). It was explained to me by a friend that used to work on these vehicles, that Mercedes rate it as 3,500kg to allow young’uns to drive it but it’s capable of 4,050kg without modification.

 

So armed with the new COC/letter it was sent to the DVLA (I was also given a new plate sticker). I kept checking every week on the DVLA tax check page, and yesterday they had finally changed my weight. I presume that means a new V5 is on its way, and I will be able to check my tax rate.

 

So worth doing a bit of digging on the internet and even chatting to the manufacturer, it may save you having to spend any money.

 

Cheers

 

Steve

 

Steve,

 

Unfortunately Terry's 316 is NOT the same as your 316!

 

You have a 2018 which will be an NCV3 or '906' series whereas Terry has a 2002 which is a T1N or '903' series.

 

I have a T1N 903 and was advised by SV Tech that to increase the GVW and more importantly the rear axle limit I had to have auxiliary air suspension fitted (already done) and then to utilise the 'Low speed' rating of the tyres.

 

Our tyres are 225/70 R15C 112/110 (115N).

 

The 115N means we could increase the rear axle load from the current 2,240 kg (LI 112) to 2,430 kg (LI 115) BUT the maximum speed at the increased load would be 87 mph (SSY N).

 

Keith.

 

Hi Keith,

 

I stand corrected :-D

 

Cheers

 

Steve

[broket]

Doh!

 

I cut and pasted from the advert=225/70 R15 100T N.

 

THANKS KEITH.

 

Actual: 4x 225/70R 15C 112/110 R (I will cut and paste from HERE from now on :)

 

Interesting that any tolerance is baked in from the get go. I will ring Italy later.

 

It's still a mystery to me - all folks in the front of the vehicle along with the engine and it's the lowest rated axle.

[Keithl]

broket - 2019-06-29 9:11 AM

 

Doh!

 

I cut and pasted from the advert=225/70 R15 100T N.

 

THANKS KEITH.

 

Actual: 4x 225/70R 15C 112/110 R (I will cut and paste from HERE from now on :)

 

Interesting that any tolerance is baked in from the get go. I will ring Italy later.

 

It's still a mystery to me - all folks in the front of the vehicle along with the engine and it's the lowest rated axle.

 

OK Thanks for clarifying your tyre size and rating, that sounds good!

 

As for individual axle weights, can you drive to a weighbridge and get your OH to follow in a car with the kids then all climb aboard for the weighing? At least you would get an idea of whether the up-rating would work.

 

Keith.

[broket]

:)

 

I am organizing a trip to the weighbridge as we speak.

 

I may change the tyres anyway. OH thinks it's a waste as there is over 8mm of tread (on the non premiums fitted) but ... we are doing thousands of miles and 'A' rated Goodyears (for example) would save a lot of diesel over time. More than making up the price per corner in that trip one alone.

 

 

[Keithl]

broket - 2019-06-29 9:57 AM

 

:)

 

I am organizing a trip to the weighbridge as we speak.

 

I may change the tyres anyway. OH thinks it's a waste as there is over 8mm of tread (on the non premiums fitted) but ... we are doing thousands of miles and 'A' rated Goodyears (for example) would save a lot of diesel over time. More than making up the price per corner in that trip one alone.

 

 

Keep the old tyres then sell them on fleabay to offset the cost of your new tyres. You will also save the 'recycling' cost on your bill!

 

Keith.

 

PS Make certain you get 'HIGH PRESSURE' valves fitted to handle your high pressures. There was a recent thread on here with good info.

[mikefitz]

Even uprated you cannot legally overload the axle. With the sprinter and over cab accomodation the vehicle will be running near or perhaps over the front axle limit.

 

Most of my driving is in Europe in a pvc and been stopped and weighed three times in recent years, twice in France and once in Germany. The Germans were very keen on all aspects of the van, checking tyres, lights and looking around for any faults.

Mrs Mike, ex language teacher, asked what would happen if there was a problem. We were told there would be a fine and not be able to continue unless the load was reduced. There was evidence of this with other motorhomes and vans that had been stopped making efforts to comply. Apparently if they considered the vehicle un roadworthy they could impound the vehicle.

The French were only interested in weight. Again we were told there would be a fine and the need to remove any overload before being allowed to continue. It was suggested a minor overload was less serious and the vehicle could be allowed to continue, I suspect this consession would only be for the French.

 

Mike

[Derek Uzzell]

Keithl - 2019-06-29 10:04 AM

 

broket - 2019-06-29 9:57 AM

 

:)

 

I am organizing a trip to the weighbridge as we speak.

 

I may change the tyres anyway. OH thinks it's a waste as there is over 8mm of tread (on the non premiums fitted) but ... we are doing thousands of miles and 'A' rated Goodyears (for example) would save a lot of diesel over time. More than making up the price per corner in that trip one alone.

 

 

Keep the old tyres then sell them on fleabay to offset the cost of your new tyres. You will also save the 'recycling' cost on your bill!

 

Keith.

 

PS Make certain you get 'HIGH PRESSURE' valves fitted to handle your high pressures. There was a recent thread on here with good info.

 

Unless the Kentucky Camp’s tyres are elderly (at least more than 5 years old) as they have some 8mm of tread-depth (which is approaching the depth of many new light-commercial vehicle tyres) I sympathise with Terry’s wife’s view. Tyre-age can be confirmed by the date code

 

https://www.kwik-fit.com/tyres/information/tyre-age

 

and it’s naive (in my view) to believe that replacing ’non premuim’ tyres (It would still be useful to know the make and name of the Kentucky Camp’s present tyres) with ‘premuim’ tyres (eg. manufactured by Michelin, Goodyear, Continental, Hankook etc.) will automatically produce a radical reduction in fuel consumption whatever a tyre's labelling might suggest.

 

For safety and on-road performance (including optimised fuel consumption) It’s critical that tyres are sufficiently inflated, and the entry for a 225/70 R15C 112 tyre in Continental’s current technical handbook advises 3.0bar/44psi for an axle-load of 1600kg and 4.5bar/65psi for an axle-load of 2240kg.

 

An inflation pressure of 4.5bar/65psi does not demand that ‘high pressure’ tyre valves be fitted. I suspect that Terry’s motorhome currently has ordinary snap-in rubber ‘car’ tyre valves and, if its tyres were replaced, there’s every likelihood that new valves of that type would normally be fitted. There’s nothing preventing ‘high pressure' valves (snap-in or clamp-in type) being used instead, but Terry would probably need to insist that this be done and possibly provide the appropriate valves himself.

 

The recent forum thread Keith mentions may be one of these

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Dust-caps/52186/

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Tyre-Pressures/52281/#M610011

[broket]

Sorry Derek, I cross posted and missed this very interesting information.

 

Yes I miss wrote about what was said to me. As soon as .gov have passed the paperwork.

 

I am going to strip the weight out of it just to get some leeway in both scenarios. The missus seems happy though. It can't last ;)

 

 

 

[broket]

Current tyres are:

 

Front- matched pair Austone. Receipt 13 months old. @800 miles on them and they look like they were put on yesterday.

 

Back- matched pair Infinity. Receipt 24 months old - so I guess 3 MOTs ago. @1800 miles and the tread depth is a cigarette paper less than the front on the gauge.

 

I tend to believe Kwik Fit exaggerate just a tad when their corporate bumph says 20% of fuel consumption is contact patch and the difference between (EU) A and E can be 7.5% so 1/3 which is not insignificant to my mind. I do bow to greater knowledge though. Saying that, the Father-in-law insists on low rolling resistance (Michelin if I remember which it's possible I don't) tyres all around on his main vehicle and has been driving the same make of car for 20 years. He claims between 1 and 2 MPG compared to, and I quote "bog standard ****" The price difference pays him back "smartish".

 

 

[Ocsid]

Unless the quoted difference is 7.5% of that 20%, so in real terms could amount to 1.5% of the fuel consumption, and even that is assuming the tyres are at the extremes of bad and best. Inflating properly, as high as recommended, probably amounts for the same difference.

[colin]

I've done a few calcs on swapping the tyres to Continental Van 100's which are I believe the best rated for economy in the size etc, have made a few estimates of what your present tyres are rated at and guesimated mpg and life. If the figures are to be believed you will save about £400 in fuel over the life of the tyres, which is about what the set of Conti's will cost, if you sell the present tyres on ebay you will be in profit, but better than that as far as I can see you will have tyres with better grip and that are quieter. It's all a bit 'back of a fag packet' so might not work that well, personally I'm more interested in grip levels and road noise which would normally swing it to Conti's for me (I've got a pair on the van now), but I am thinking of Michelin Cross Climates (which I have on a 4x4) for my next tyres.

[aandy]

The most important words in all these fuel saving claims are "up to", which in invariably means "less than" and of course includes none. My current tyres are three points up on the last and after 8,000 miles fuel consumption is exactly the same.

[Derek Uzzell]

I’m guessing that the Austone tyres (made in China) are these

 

https://tyres.buycarparts.co.uk/austone-2080002574790-9225020971

 

and the Infinity tyres (made in the UAR) are these

 

https://www.oponeo.co.uk/tyre-details/infinity-eco-vantage-225-70-r15-112-110-r

 

A “C” fuel efficiency rating is quoted for the Austone product and an “E” rating for the Infinity tyre.

 

Tyres intended for light-commercial vehicles tend not to have an ultra high fuel-efficiency-rating ‘letter. A “C” letter is commonplace and an “E” letter is far from rare. It will be seen from this advert

 

https://tyres.buycarparts.co.uk/hankook-8808563386928-2020363

 

that the Hankook Vantra LT RA18 in 225/70 R15C specification has a fuel efficiency “E” letter, but this tyre (in 215/70 R15C size) was well in front of five others in an independent test carried out by ProMobil motorhome magazine in 2013. So, although the Hankook tyre may be less fuel efficient than (say) Continental’s VanContact 100 that has a “B” letter (and was discussed here 5 years ago)

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Continental-Van-Contact-100-225-70-R15-112R-C-summer-tires/34823/

 

the only independent comparative test I’m aware of suggests that - if wet weather performance were of particular importance - the Hankook product would be the rational choice.

 

There are far too many variables involved in trying to calculate potential financial benefits in replacing the existing near-new “C” and “E” rated Austone/Infinity tyres with (say) “B”-rated VanContact 100 tyres. All that can be said for sure is that, even if the Austone/Infinity tyres are subsequently sold, the cost of the replacements will exceed what the Austone/Infinity tyres can be sold for. Four Hankook RA18s would cost about £320 and maybe one could get £30 for each Austone/Infinity tyre - so perhaps an outlay of around £200 for a set of brand-new tyres with a good reputation (but overlooking the “E” fuel-efficiency letter) and getting rid of the unknown-quantity Austone/Infinity tyres.

 

(What tyre is on the Kentucky Camp’s spare wheel and how old is it?)