Sat nav and speed limits

[pottypam]

Our MH has a MGW of 3500 kg. Speed limits for the UK refer to unladen weights below or above 3050kg. How do we find the unladen weight? Our sat nav (Garmin) is giving speeds of 50mph on A roads even though we have entered the weight as 3010; our previous one (Snooper) gave 40mph, although it changed to 60 on roundabouts! We spent a year emailing them to try to solve this, eventually giving up and getting the Garmin.

 

Any advice, please?

[Robinhood]

...you may not need to determine the unladen weight, as it will be (usually quite a bit) below the MIRO (Unless you've fitted a lot of weighty accessories).

 

See if you can find the quoted MIRO for your 'van, or alternatively post details of the make and year, and someone can probably find the figure.

 

Most (though not all) 'vans plated at 3500kg will have an unladen weight of 3050 or lower ex-factory.

 

As far as the Satnav is concerned, I suspect it is (generally, the roundabouts are an anomaly) giving you the limits for a commercial vehicle at your quoted/input weight, either by assumption from the weight, or because you are using a truck/lorry setting. Whilst motorcaravans have the same limits as cars (up to 3050kg) commercial vehicles do not.

[pottypam]

Thanks, Robinhood. The Garmin sat nav is set up for a motorhome as was the previous Snooper. Just wondering if others have the same problem?

[Brian Kirby]

Simplest answer to the weight of the van is to empty it of all loose items, fill the fuel tank, and take it to a weighbridge. If the weight is close to 3050kg (which I doubt it will be, but you havent confirmed make and model), deduct the weight of the full tank of fuel at 0.85kg/L, so for a 80L tank full, the weight would be 68kg. Unladen means absolutely empty: no gas, no fuel, no water, and only a jack, starter battery and engine oil present. So, the above would be the nearest approximation that can be achieved.

 

But, if the weighbridge ticket confirms the reg number of the vehicle and is dated (as it should be), and shows the van weighing 3050kg or less, the fact that you were able to drive it to, and from, a weighbridge should be evidence sufficient for anyone who needs to know, that if presented at a weighbridge in full "unladen" state it would weigh even less.

 

Just be aware that if abroad the weight at which speed limits change is its MAM (i.e. 3,500kg) and not 3050kg.

[pottypam]

Thanks, Brian.

 

It is an Autotrial Imala 615, 2014. We don’t have the van and it’s documents at the moment (in for repair) but an outandabout review for the 2015 model gives MGW as 3500kg with a payload of 490kg, so MIRO of 3010 which would be higher than the unladen weight. This is the weight we have entered in the sat nav and we are getting 50 Mph limits on ordinary roads, haven’t yet tried it on motorways.

[Robinhood]

I think it will be a 2015 model year (as I can't find any Imala in the 2014 brochure), and the MIRO without options is indeed quoted as 3010kg.

 

If you've not (permanently) affixed heavy accessories, you patently should be below the 3050kg unladen weight, even allowing for any build variance, since the MIRO includes 75kg for the driver, and an allowance for fuel and (minimal) gas which is going to be close to 100kg (neither of which should be counted for the unladen weight). Remove the tools as well, and the unladen weight should be somewhere around the 2900kg mark.

[colin]

pottypam - 2018-04-28 6:02 PM

Our sat nav (Garmin) is giving speeds of 50mph on A roads even though we have entered the weight as 3010;

 

Your satnav appears to be assuming you are driving a van as apposed to a motor caravan.

[Derek Uzzell]

This 2017 forum thread referred to sat-navs and the 3050kg unladen-weigh’ datum

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Why-doesn-t-my-satnav-say-this-/46779/

 

and it might be worth ploughing through this 2009 discussion

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/SPEED-LIMIT/15936/

 

This gov.uk webpage

 

https://www.gov.uk/vehicle-weights-explained

 

defines unladen-weight as follows:

 

"Unladen weight

 

The unladen weight of any vehicle is the weight of the vehicle when it’s not carrying any passengers, goods or other items.

It includes the body and all parts normally used with the vehicle or trailer when it’s used on a road.

It does not include the weight of:

- fuel

- batteries in an electric vehicle - unless it’s a mobility scooter or powered wheelchair”

 

Speaking as an ex computer programmer, entering a weight of 3050kg into a ‘camper’ sat-nav should be expected to have an unpredictable result as far as UK speed limits are concerned as the 3050kg threshold is peculiar to this country and the sat-navs are not produced here.

 

This webpage lists motorhome-related UK speed limits and also expands on the unladen-weight definition

 

https://www.ukmotorhomes.net/motorhome-faqs/speed-limits

[flyboyprowler]

We use the Garmin Camper 760, and with the correct weights put in for our van, the speed limits displayed are invariably wrong. Garmin tell me that they get their information from outside agencies, and that only map inaccuracies can be submitted on an on line form.

 

Our use is generally on the continent, and speed limit accuracy varies from country to country, with France probably best. I don't think that it would be realistic to have every limit displayed, but it is frustrating to see 80kph shown when the national limit is 90kph, or in Spain 70kph shown in 90kph areas! However in the UK, I have found the limits to be mostly accurate.

 

Previously, I had a long email conservation with Garmin in the USA, on this subject, but got nowhere, although they at least had the decency to reply, but with the suggestion that I had the wrong van weight selected, which was not right, and indeed changing the weight, (and we are over 3500kgs) didn't make a difference.

 

I am tempted to buy the new 770 camper, to see if the limits are now correct!

[Brian Kirby]

pottypam - 2018-04-28 8:11 PM

 

Thanks, Brian.

 

It is an Autotrial Imala 615, 2014. We don’t have the van and it’s documents at the moment (in for repair) but an outandabout review for the 2015 model gives MGW as 3500kg with a payload of 490kg, so MIRO of 3010 which would be higher than the unladen weight. This is the weight we have entered in the sat nav and we are getting 50 Mph limits on ordinary roads, haven’t yet tried it on motorways.

But MAM - payload does not = unladen weight, which has a specific definition under (I think) the Construction and Use Regulations. Unladen is, in a (simplified! :-)) nutshell, the ex-works weight of the vehicle with only engine oil and coolant, plus the starter battery and, I think essential tools (i.e. jack and wheel-brace), present, but with an empty fuel tank.

 

The problem with the figures you are quoting is that a) they are not vehicle specific (motorhomes are notorious for varying in weight from the manufacturer's MIRO figure: with even two apparently identical motorhomes of the same brand, model, and specification, being likely to vary appreciably), b) that MIRO includes a number of items that unladen omits, and c) that options added (engine and transmission options, chassis upgrades, air conditioning, awnings, sat dishes, TVs, solar panels etc.) all increase the unladen weight, but will not be included in the manufacturer's MIRO figure which will normally be based on the most basic specification offered.

 

You are very likely to be right that if the manufacturers MIRO is less than 3,050kg your actual unladen weight will also be less than 3,050kg but, if you really want peace of mind, and complete confidence, a weighbridge ticket is the only way to go. Written evidence trumps approximation! :-D

 

Just as an aside, do not rely on what sat-navs say about speed limits. The data on which their mapping is based is inevitably out of date as speed limits get changed here and there all the time, all over Europe, and the mapping cannot be expected to be correct in all situations and places. The sat-nav is extremely good at accurately telling you your road speed (better than the speedometer) but, if you want to know the speed limit, the roadside signs are the only reliable (and legal :-)) guide.

[pottypam]

Thanks everyone for your comments. It seems that the sat navs sold here will all give inaccurate speed limits for Motorhomes on UK roads so we will keep to the posted limits and turn off the audio alert.

[Derek Uzzell]

As Brian has said, speed limits are in constant flux and sat-nav data cannot be expected to be immediately corrected to reflect each alteration.

 

I’ve come across the occasional instance in the UK where it’s plain that my Garmin sat-nav’s speed limit data for a particular stretch of road is out of date, and this is despite having updated the device’s software not long before. But most of the time the speed limit data is accurate.

 

3500kg is a general weight threshold for vehicles: up to that weight a vehicle will (essentially) be considered to be a ‘car’ and above that weight consideredto be a ‘truck’. I suspect that the software used for ‘camper’ sat-navs is the same as that used for ’truck’ equivalents, so inputting a weight factor into such devices should produce either ‘car’ or ’truck’ speed limit outputs. I’d also guess that specifying a vehicle as being a ‘motorhome’ will cause it to be treated as a ‘truck’.

 

I’ve never owned/used a sat-nav that allows vehicle dimensional and/or weight data to be input, but both of my common-or-garden Garmin devices are generally accurate in the UK and France when it comes to reporting speed limits.

 

For my 640F model Rapido quotes a mass-in-running-order of 2795kg (so the unladen weight would be less than that) which makes the motorhome very much a ‘car’ with ‘car’ national speed limits applying to it. Obviously, if the Rapido had an unladen weight over 3050kg my Garmin sat-navs’ speed limit readouts would be wrong for the UK, and if the vehicle had a maximum authorised mass above 3500kg (which the 640F model does not) the speed limit readouts would be wrong outside the UK.

 

But for any motorhome UK-registered in the Private/Light Goods taxation class, a standard ‘car’ sat-nav should (realistically) be trustworthy when reporting speed limits.