KERB WEIGHT

[pauloneill]

hello out there
i want to purchase a bailey 430 4 berth mtplm 1247 miro1100kg but am a bit confused as i keep getting differnt answers on my astra 1.7 cdti 2008 model
my reg cert says max perm mass 1855
mass in service 1365
technical permissible max towable massof traler 1400 braked
i think my kerbweight is 1290 but not sure cant find anything on the vehicle
can i tow with no problems
thanks in advance

 

[ProfJohnL]

Hello Paul,

You have the most reliable source of information - your registration document.

Kerbweight is not an official term which is why you are having difficulty if finding it quoted. However you have got a Mass in Service, which is probably as close as you will get to the kerbweight.

Using the information you have provided your proposed outfit will have an approximate towing ratio of 100 x 1247/1365% = 91%

Good sense suggests you should have a ratio that is a small as possible, The Caravan industry suggest a new caravanner would be wise to keep the ratio below 85%, so your outfit is greater than they suggest. to get a lower ratio you will either need to choose a smaller caravan or get a heavier car.

Good towing is not just the result of getting a precise towing ratio, it involves getting a range of criteria under control, things like how you load the caravan, the nose weight, and assuming the car and caravan are in good condition, the biggest variable is the driver.

 

[pauloneill]

many thanks for that prompt reply
will take all on board
thanks again

 

[ProfJohnL]

Hello again Paul,

I have just re read my earlier reply , and I have perhaps left you with the impression that your current car/caravan is not satisfactory.

I should have added a little more :-

Towing ratio's are not main arbiter of what makes a good tow, As I did say there are other factors, so a few percent above the industry recommendation may be perfectly satisfactory provided everything else is well controlled.

Whilst the industry recommendation of 85% has no legal authority, the car manufacture limits do, so whilst there can be flexibility in the industry reccomendation, you must not exceed any of the manufacturers limits.

And with regards safety, no amount of advice can guarantee a safe towing outfit, so whilst the industry recommendation supports the principal of low towing ratios it doesn't ensure a good tow.

Please don't be afraid to ask any more questions.

 

[Martin24]

Yet again and for the second time this year I agree with the prof!!

 

[ProfJohnL]

Martin,
You must be ill or mellowing or beging to see the light!

The basis of my towing advice has not changed

 

[Martin24]

In agony today following removal of 4 teeth but that doesn't explain my yesterday mood????? I must of got all my flipancy out of the way on other subjects, and of course had a rant about my own damp issues as well

 

[colin-yorkshire1]

hi Paul,
while on the subject of weight ratios and recomendations I usualy agree with the Prof because his explanations are usualy accurate when the technical stuff comes out for an airing? and would both agree that idealy the trailer weight should be as light as possible on any combo,as a starting point, there are many ways to do this apart from the obvious ones though.

however and this is only a personal view you understand I also tend to look at things a little deeper in to the nitty gritty type of stuff that you would not find going through reams of technical data and sometimes use unscientific gut instinct to make my own decisions on.
a case in point was when I bought a Megane 1.9 diesel to tow our bailey which is just under 1100kg the cars kerb weight was only 1140kg so on paper would be a 97% tow ratio, however I worked out that while the weight difference was marginal with careful loading I reckond it would be ok weight wise if the engine power was sufficient to pull the total unit weight. in this I was confident as the same engine and running gear was fitted to far heavier vehicles like the Laguna, Espace, and Renault Traffic van. as it turned out I was more than pleased with it and used it for 3 years with no issues at all.

this brings me to the Astra 1.7ctdi while looking at the figures it seems ok to me with a approximate kerb weight of 1365kg against a trailer MTPLM of 1247kg it would give a tow ratio just over 90% and while a little high should be managable considering the vehicle manufacturer puts the max trailer tow load at 1400kg.

however the main question has to be wether you feel the vehicle has suffient power to pull a total weight of 3102kg or to put it another way 30kg per 1hp. in this I may be of help, based on my present unit same van but towed with a 1.7cdti meriva 100bhp the cars approximate kerb weight is 1422kg van the same 1100kg total 2522kg a little less than your preposed outfit but still in the same ball park.

I can confirm the engines power output is more than capable of towing anywhere a recent trip down the motor way gave a top gear tow @ 2300rpm "58mph" with ease, a return trip over the yorkshire moors was not too difficult however lots of gear changes were needed on the hilly bits.

in the end it's down to how you feel about it one suggestion I would make is if you are not sure try to borrow a trailer of similar weight and give it a try, if that is possible if not try the Astra owners club and ask if any members tow with the same car,

sorry if my post is a little long winded but you really have to be sure the combo will work for you as mistakes can be expensive in the long run.
colin

 

[colin-yorkshire1]

hi Paul,
following on from my last post, this moring I did a quick suitability check with the CC web site not knowing the exact model of car or van. I could not get the exact match but based on the general info given the CC puts the outfit in the adequate catagory, that is generaly ok with good performance on level roads and adequate performance on hills with the aid of some gear changing,
so in general very similar to my own findings with the Meriva, they put the power output at 34 BPH per tonne so while this is not brilliant it should be more than capable to do the job, unless of course it is the 130bhp SRI model it which case the suitability rating goes from adequate to good.

colin

 

[PeterDavenport]

I have a peugeot 407sw 1.6HDI BHP 110.Max laden weight 2127. I bought a Bailey 430/4 MTPLM 1247. If both are fully laden I would be over the Gross train weight. Are these weights for 4 people and luggage in the car and the caravan fully loaded with bedding etc for 4 people. There is only myself my wife and two dogs. Last year I towed an ABI Award daystar MTPLM 1250. When I ordered the new caravan at the caravan show I was told there would be no problem as I can tow upto 1300 on a braked trailer. One of the on line tow match sites it said I would be fine. On others it said it would be over 100% match and unsuitabe.
CONFUSING WHAT?

 

[PeterDavenport]

I have a peugeot 407sw 1.6HDI BHP 110.Max laden weight 2127. I bought a Bailey 430/4 MTPLM 1247. If both are fully laden I would be over the Gross train weight. Are these weights for 4 people and luggage in the car and the caravan fully loaded with bedding etc for 4 people. There is only myself my wife and two dogs. Last year I towed an ABI Award daystar MTPLM 1250. When I ordered the new caravan at the caravan show I was told there would be no problem as I can tow upto 1300 on a braked trailer. One of the on line tow match sites it said I would be fine. On others it said it would be over 100% match and unsuitabe.
CONFUSING WHAT?

 

[ProfJohnL]

Hello Peter,

Your experience of the on-line match guides serves to emphasis the advice I have given so often - don't accept what they come out with as being copper bottomed accurate.

Different people and organisations may have different criteria they use for establishing matches which will also give different results. There can be a difference between what is a legal tow and what is a good tow. Just be aware that an unsafe tow is always illegal, and an illegal tow may be classified as an unsafe load.

It should be obvious that a caravan is a more difficult trailer compared to say a garden trailer, and so caravans need to be treated and matched differently. Being usually bigger and heavier it makes sense to down rate the car so it has a better chance of coping.

However you ask about what constitutes full loads? There is no statutory method on what the full load should contain. The full load is a limit, and in essence it is up to the driver (who is always the responsible for the car)to ensure they do not exceed them.

 

[Surfer]

I have a peugeot 407sw 1.6HDI BHP 110.Max laden weight 2127. I bought a Bailey 430/4 MTPLM 1247. If both are fully laden I would be over the Gross train weight. Are these weights for 4 people and luggage in the car and the caravan fully loaded with bedding etc for 4 people. There is only myself my wife and two dogs. Last year I towed an ABI Award daystar MTPLM 1250. When I ordered the new caravan at the caravan show I was told there would be no problem as I can tow upto 1300 on a braked trailer. One of the on line tow match sites it said I would be fine. On others it said it would be over 100% match and unsuitabe.
CONFUSING WHAT?

Gross train weight is normally gross weight of car fully loaded plus gross braked weight of trailer so ther is no ways that you should be exceeding the gross train weight according to the figures given above.
Looking at some figures for a Peugeot 407 SW the gross weight is 2127kg, train weight 3127kg, braked trailer weight 1300kg. Fully loaded in car with gross weight at 2127kg, you can tow up to 1000kg so you would not be able to tow the caravan even if it was empty as the MTPLM shows at 1247kg exceeding the train weight.
If stopped by VOSA I think that they go by the maximum plated figures allowed on car and trailer and not by the MIRO or either unit so you may be illegal even if both units are virtually empty. Maybe someone else can clarify?
Kerbweight of car is 1567kg so

 

[ProfJohnL]

Surfers definition of Gross Train weight is ambiguous, because it implies that the GTW is dependant on the trailer you choose to tow. This is not the case, the GTW is a fixed figure decided by the car manufacture. You can use the GTW with the Gross vehicle weight (now called Maximum Authorised Mass or MAM) to establish the largest trailer weight you can tow when the car is fully loaded.

GTW-MAM= towed trailer weight.

Now some manufactures actually quote a larger towed trailer limit but to tow this larger weight you must still keep within the stated GTW and so it means you have to reduce the loading in the car so the combined weight of car and trailer still remains within the cars GTW figure.

If you are working so close to these limits then you also need to be aware that he trailers nose weight is not part of the towed weight of the trailer, but it forms part of the cars own load. this has been explained at length elsewhere on the forum.

Surfers has expressed his uncertainty about how VOSA would regard towing a trailer whose MIRO is less than the cars towed weight limit but its MTPLM exceeds it. His assertion that VOSA would only look at the MTPLM and deem the outfit too heavy is wrong. The regulations refer to the weight (or mass) of the outfit not its weight limit. You could not be prosecuted for an over weight vehicle unless there is documentary evidence to prove it. You could possibly be prosecuted for an overloaded vehicle if in the substantiated opinion of the officer a trailer was too large or unsafe.

 

[Surfer]

Surfers has expressed his uncertainty about how VOSA would regard towing a trailer whose MIRO is less than the cars towed weight limit but its MTPLM exceeds it. His assertion that VOSA would only look at the MTPLM and deem the outfit too heavy is wrong. The regulations refer to the weight (or mass) of the outfit not its weight limit. You could not be prosecuted for an over weight vehicle unless there is documentary evidence to prove it. You could possibly be prosecuted for an overloaded vehicle if in the substantiated opinion of the officer a trailer was too large or unsafe.

I think that there is a good possibility that you could be wrong on the above. If for example your car is plated to tow a braked trailer with an MTPLM of 1500kg, but the braked trailer you are towing has a plated MIRO of 850kgs and MTPLM of 2200kg and you are towing it empty, you are guilty of an offence proabaly under the Roads and Construction Act as there is possibility of an offence being committed. It would not be up to VOSA to show that the gross train weight of the outfit is under the legal gross train weight of the car. One of the reasons why weights are on the VIN plate.

 

[ProfJohnL]

Hello Surfer,

I am confident that given the circumstances you suggest there would be no weight offence based on the vehicle capability, and the trailers capacity. The crux is that the actual (Measured) weights are still within limits.

However it is possible a driving licence offence may have been committed, if the driver only has a B entitlement. where the combined MAM of car and trailer must not exceed 3500Kg, and the trailers MTPLM must not exceed the cars MIRO. There woudl be no problem for drivers with BE entitlments

 

[colin-yorkshire1]

hi guys' think we have been here before so here's my slant on it
A. if the MTPLM is the important figure ie maximum ammount of user payload + MIRO, and not the actual tow load ie what it really weighs,
then B. a car transporter weighs the same wether it is carrying a car or not, and a horse box can be over weight without horses,

I would like to see how VOSA having stopped a outfit and weighed it "something they allways do" and found it within limits then try to proceed to prosecute because the plated weight is more than the actual weight was at the time of testing.
if that is the case then why use weight scales

 

[Parksy]

And here is where useful debate containing information ended..............
Apologies to anyone who feels that they have been unjustly treated because I removed posts after this point but the debate has ranged so far off topic from the OP as to become confusing and contradictory.