Jump to content

Weight Clarification


GARYSJ
 Share

Recommended Posts

Something to bear in mind, if you buy a big heavy caravan and plan on keeping it for quite some time, you are also going to have to keep a big heavy car to tow it. If we change our caravan I would prefer to go for one a lot lighter (current one MTPLM 1499 kg) to give a greater choice of tow car. However, when I last looked at caravans and found one I liked, it weighed just the same and what appeared to be lighter ones had the same MIRO but  a lower payload so not really any lighter.

 

This has not been mentioned but I guess you already have the B+E driving licence to tow with a gross train weight over 3500 kg.

 

I would not think easier straight line reversing and safety on a blow out would be good reasons to justify a T/A, it ought to be you prefer the T/A since you like it better due to size and layout that suits your needs. Most reversing would be done when positioning on a site or back at the storage but on a T/A a mover would be needed any way so most would use it to site a caravan. TPMS is the way to go if worried about a possible puncture on any caravan.

 

The caravan nose weight should be adjusted to be the lowest of the car, its tow bar or the caravan. The car should be in its hand book, same with a caravan but is often 100 kg and as GaryB1969 has mentioned, the tow bar will have a sticker with its limit on it.

Link to comment
Share on other sites

  • Replies 82
  • Created
  • Last Reply

Top Posters In This Topic

38 minutes ago, GaryB1969 said:

It should be on the tow bar rating plate, shown as the "S" value.

Thanks I will ask 

Link to comment
Share on other sites

The towing limit is the maximum the car can restart five times on a 12% gradient and has nothing to do with safety but is more a measure of the strength of the drive line. Towing at that figure may be legal but could be very unsafe.. The problem with caravans is the very large flat sides which can be subject to cross winds, what you need is a car with sufficient weight to control the caravan and the 75% figure is the basis of this although, to me is a bit too pessimistic. Having said that for a beginner I would stick somewhere below 90%.

Towing in excess of the cars kerb weight is frankly dangerous with many outfits, although many people have tried it and got away with it. As someone who had to investigate the accidents I can assure you it is not a good idea and can be positively dangerous in an emergency situation. Flatcoat888 may have towed at the weights he suggests but unless he had a severe and dangerous situation he could not be sure how safe it was. 

Twin axle models are reputed to tow better than single axle ones, but caution as a beginner is the best option. 

If the figure you give for the kerb weight does not include the driver and a load the formula allows 75 KG for these.

Personally I would be looking at something up to 1,600 kg but you have to decide how  cautious you want to be. 

Link to comment
Share on other sites

8 hours ago, GARYSJ said:

Merc E class Estate 4matic

Easier straight line reversing  and safety on a blow out. 

Merc E class estate 4matic

Hoping to get one for August, so 8 weeks search window. The club courses are booked up or not till Sept. However the 1-2-1 idea is great. Any idea where such a instructor can be found. We are in Essex. 

I’m towing a MTPLM 1605kg single axle with a C-Class estate C250CDI with a kerb weight of 1650kg. You’ll be just fine if you take it easy especially with the extra axle weight the 4matic adds. In fact That is going to be my next vehicle of choice for towing as it has the send levelling rear suspension and a higher nose weight limit of 85kg compared to my 75kg.

7 hours ago, GaryB1969 said:

I looked at (and ordered) a Mercedes E Class estate back in 2019. I never got the car due to redundancy BUT I did discover that published Mercedes kerb weights were the MINIMUM for that range, so anything over & above a base model with extras will be heavier. The only negatives I found during research related to soft rear suspension (something my Volvo also suffers with).

Iv found this over my C class estate. The kerb weights do not accurately reflect my cars weight as it has AMG kit including upgrade stiffer suspension, brakes (bigger heavier discs), panoramic sun roof, heated seats, Mercedes roof rack system and command system. All of these add a fair bit of extra weight I suspect. At 204bhp and 500nm torque it’s no slouch either. You have to judge each individual car on it’s own merits.

Link to comment
Share on other sites

16 minutes ago, Pembssurfer said:

I’m towing a MTPLM 1605kg single axle with a C-Class estate C250CDI with a kerb weight of 1650kg. You’ll be just fine if you take it easy especially with the extra axle weight the 4matic adds. In fact That is going to be my next vehicle of choice for towing as it has the send levelling rear suspension and a higher nose weight limit of 85kg compared to my 75kg.

Iv found this over my C class estate. The kerb weights do not accurately reflect my cars weight as it has AMG kit including upgrade stiffer suspension, brakes (bigger heavier discs), panoramic sun roof, heated seats, Mercedes roof rack system and command system. All of these add a fair bit of extra weight I suspect. At 204bhp and 500nm torque it’s no slouch either. You have to judge each individual car on it’s own merits.

Thanks. I believe it has rear air suspension as standard. How do you find the nose weight. This car has a Merc fitted tow ball. 

Link to comment
Share on other sites

6 minutes ago, GARYSJ said:

Thanks. I believe it has rear air suspension as standard. How do you find the nose weight. This car has a Merc fitted tow ball. 

Merc normally have it in the manual tech specs. Should be available online too . I’d hazard a guess at 85kg as Iv not seen higher than that in an E-Class

Link to comment
Share on other sites

1 hour ago, Wildwood said:

.

Towing in excess of the cars kerb weight is frankly dangerous with many outfits, although many people have tried it and got away with it. As someone who had to investigate the accidents I can assure you it is not a good idea and can be positively dangerous in an emergency situation.

 

And the evidence to support that very broad, sweeping, and as yet totally unsubstantiated, statement can be found where exactly?? 

 

As someone who  has been involved with the forensic investigation, and reconstruction of serious traffic collisions over many years for both Coroners and Crown Courts I have never heard such a statement ever being used, or even suggested!

 

If the vehicle manufacturer  warrants their product as capable, and by association perfectly safe, of towing up to a certain weight then I would suggest they they have done their research, and their sums very carefully indeed ( think in terms of “Product liability)

 

If  they have not, or it transpires they have got it wrong,  the consequences (and the costs to them) are likely to be exceedingly far reaching indeed.  It would make VW and dieselgate look like small change, let alone the reputational damage.

 

Just think of the possible headlines “Car manufacturer sells car with incorrect and dangerous towing capacity” 

 

.

Experience is something you acquire after you have an urgent need for it.

Link to comment
Share on other sites

2 hours ago, Wildwood said:

The towing limit is the maximum the car can restart five times on a 12% gradient and has nothing to do with safety but is more a measure of the strength of the drive line. Towing at that figure may be legal but could be very unsafe.. The problem with caravans is the very large flat sides which can be subject to cross winds, what you need is a car with sufficient weight to control the caravan and the 75% figure is the basis of this although, to me is a bit too pessimistic. Having said that for a beginner I would stick somewhere below 90%.

Towing in excess of the cars kerb weight is frankly dangerous with many outfits, although many people have tried it and got away with it. As someone who had to investigate the accidents I can assure you it is not a good idea and can be positively dangerous in an emergency situation. Flatcoat888 may have towed at the weights he suggests but unless he had a severe and dangerous situation he could not be sure how safe it was. 

Twin axle models are reputed to tow better than single axle ones, but caution as a beginner is the best option. 

If the figure you give for the kerb weight does not include the driver and a load the formula allows 75 KG for these.

Personally I would be looking at something up to 1,600 kg but you have to decide how  cautious you want to be. 

I will put the car on weigh bridge with the two of us in the vehicle to get the true car weight with quarter fuel tank. 

Link to comment
Share on other sites

Having had to deal with the accidents, the simple answer is I have not seen one loss of control accident where the towing ratio has been suspect. That is not to say they have not happened, but it is clear to me that the towing ratio can be a problem if it is too high, and that is where the majority of these accidents occur.

Personally I think 85% is possibly too low and 90 % should work for newcomers, but regard 95% as about the safe limit for others bearing in mind not all tow cars or caravans are equal. You simply do not have the ability to check out the combination before you buy and so common sense means a safety margin must be there. 

Link to comment
Share on other sites

The kerbweight that's used in the calculation is the car manufacturer's figure, not the actual weight of the vehicle. This is because the recommendation was originally published as a guide to car/caravan matching, back in the day when very little information about weights were published and kerbweight was one of the few readily accessible bits of info. You will find the weight published in your car's brochures and on their website. Kerbweight never involves a passenger but is either quoted with or without  a 75kg allowance for a driver. These days manufacturers tend to quote a minimum kerbweight and a maximum to allow for a variety of trim levels for a particular engine/transmission variant. So, you have to take a punt somewhere between those figures depending on where your car fits in the trim food chain. A better guide is the 'Actual Mass of the Vehicle' which is item 13.2 on your car's Certificate of Conformity.

 

As said, the towing limit is purely a measure based on the cars ability to start a trailer of that weight on a 1 in 8 hill, it says nothing about how a caravan, or anything else handles and for that reason I always work to only pull a caravan several 100kg less than the towing limit.

 

In reality when you're towing with an averagely loaded car and a fully loaded van, which is the norm, then the towing ratio, if the rig is initially 85%, is about 70% to 75%. If you start off with 100% then in reality, when loaded for action you're running at about 85% to 90%.

I've got nothing to do on this hot afternoon

but to settle down and write you a line.

Link to comment
Share on other sites

Another factor is when the guidelines were set up in the UK 35 or so years ago, car and caravan safety aids were minimal. No ABS, no ATC, no car stability systems, no TPMS and so on. As i have mentioned before, it only seems to be the UK that gets hung up on this issue and i have yet to see any evidence that countries without such guidance have a higher rate of caravan accidents. Ultimately it is your call as to what level of confidence you have.  

Link to comment
Share on other sites

11 hours ago, GARYSJ said:

I will put the car on weigh bridge with the two of us in the vehicle to get the true car weight with quarter fuel tank. 

This is truly the best and most sensible thing you can do and I think you surprised at the overall weight.

Link to comment
Share on other sites

12 hours ago, GARYSJ said:

I will put the car on weigh bridge with the two of us in the vehicle to get the true car weight with quarter fuel tank. 

 

If you're going to use the 85% recommendation then measuring the actual loaded weight of the vehicle at any one time won't give you the kerbweight, it will be the actual weight, which the 85% wasn't designed to use. I would say look at the manufacturer's towing limit and get a van with an MTPLM 200kg below that figure for a new tower and 100kg below it if you're experienced. 

 

I'll use the late departed Yeti as an example:

 

1.2 Petrol Kerbweight between 1265kg and 1285kg, so say 85% = 1084kg. Towing Limit is 1200kg. I'd go for a van 1000kg MTPLM for a newbie 1100kg for experienced.

 

2.0 110PS Diesel Kerbweight 1377kg, 85% = 1170kg. Towing Limit 1500kg. I'd opt for 1300kg MTPLM for someone new to towing and 1400kg for someone experienced.

 

At the top of the range the 2 litre 150PS 4x4 Diesel Kerbweight 1500kg, 85% = 1275kg. Towing Limit is 2100kg. I'd go for 1900kg as a newbie and 2000kg when experienced. 

 

Again, if you're going to use the 85% don't get hung up on identifying the actual kerbweight for your model, down to the nth degree because,taking the first Yeti mentioned above, nobody will ever notice the difference between 85% of 1265kg (1075kg) and 85% of 1285kg (1092kg). So if the maker gives a range of kerbweights, opt for the middle and use 85% of that, it will be near enough for your purposes.

I've got nothing to do on this hot afternoon

but to settle down and write you a line.

Link to comment
Share on other sites

Check the weights youve stated for the 4x4 Yeti! 2000kg is a bit on the high side... 

Link to comment
Share on other sites

13 hours ago, Wildwood said:

Having had to deal with the accidents, the simple answer is I have not seen one loss of control accident where the towing ratio has been suspect. That is not to say they have not happened, but it is clear to me that the towing ratio can be a problem if it is too high, and that is where the majority of these accidents occur.

 


It seems somewhat difficult to reconcile the statement highlighted above, with the one highlighted below.,.

 

15 hours ago, Wildwood said:

 

Towing in excess of the cars kerb weight is frankly dangerous with many outfits, although many people have tried it and got away with it.

 

A majority of incidents I dealt with over the years involving caravans having fallen over involved Disco’s or similar large and heavy tow cars with a low percentage ratio of tow car to caravan!  Very few involved cars which tends to suggest your assertion about a high percentage ratio being somehow “dangerous”  per se. I accept 100% that a caravan can, and does, act as a huge sail on occasions but if it’s correctly loaded (and not overloaded) and the car is driven with a modicum of care then there is nothing inherently dangerous provided none of the weights are exceeded. 

 

In what capacity have you dealt with these caravan accidents? Fire, Police (traffic or response/patrol) Ambulance, recovery agent?,

Experience is something you acquire after you have an urgent need for it.

Link to comment
Share on other sites

Not wishing to tar all Discovery drivers with the same brush, but from what I've seen on the road, there is an element within their cohort that can be accused of speeding and over confidence. Perhaps the car's do engender a feeling of indestructability, perhaps they believe the hype, perhaps a few believe they're special, perhaps you get the same proportion of numpties driving any brand, but because so many Discoveries are used for towing you see more of them.  

I've got nothing to do on this hot afternoon

but to settle down and write you a line.

Link to comment
Share on other sites

9 minutes ago, Steamdrivenandy said:

Not wishing to tar all Discovery drivers with the same brush, but from what I've seen on the road, there is an element within their cohort that can be accused of speeding and over confidence. Perhaps the car's do engender a feeling of indestructability, perhaps they believe the hype, perhaps a few believe they're special, perhaps you get the same proportion of numpties driving any brand, but because so many Discoveries are used for towing you see more of them.  

 

My point is that a Disco will, by nature, have a low percentage ratio between tow car and caravan, yet seem to be involved in a disproportionate number of “falling over” incidents, which tends to fly in the face of Wildwoods assertion that high percentages “are more dangerous” than lower ones :unsure:

Experience is something you acquire after you have an urgent need for it.

Link to comment
Share on other sites

17 hours ago, Wildwood said:

The towing limit is the maximum the car can restart five times on a 12% gradient and has nothing to do with safety but is more a measure of the strength of the drive line.

 

15 hours ago, Steamdrivenandy said:

As said, the towing limit is purely a measure based on the cars ability to start a trailer of that weight on a 1 in 8 hill, it says nothing about how a caravan, or anything else handles and for that reason I always work to only pull a caravan several 100kg less than the towing limit.

 

I'm sure I read recently on this forum a post from someone that had worked for a car manufacturer. They stated that this was not the case. Towing limits are based on rather more than hill starts?

Link to comment
Share on other sites

Posted (edited)
1 minute ago, Scarab said:

 

 

I'm sure I read recently on this forum a post from someone that had worked for a car manufacturer. They stated that this was not the case. Towing limits are based on rather more than hill starts?


Lutz mentioned it. From memory he worked for GM/Opel in a technical position.

Edited by GaryB1969

2018 Volvo V90 and 2018 Swift Sprite Quattro EB

Link to comment
Share on other sites

3 hours ago, Scarab said:

 

 

I'm sure I read recently on this forum a post from someone that had worked for a car manufacturer. They stated that this was not the case. Towing limits are based on rather more than hill starts?

 

Lutz has mentioned that on a number of occasions but IIRC the additional parameters weren't involved in determining the stability of a towed caravan. They were things like strength of towbar attachment to body structure, braking capability, overheating of transmission, cooling of the engine.

I've got nothing to do on this hot afternoon

but to settle down and write you a line.

Link to comment
Share on other sites

Most definitely are far more tests than simple hill starts.

Link to comment
Share on other sites

There are many new cars, especially hybrid versions, not approved for towing, or with very low towing limits.  You can often find the petrol or diesel ICE version is type approved to tow, and the full or plug-in hybrid version is not or has a very low limit. The battery weight eats into the train weight. 

Link to comment
Share on other sites

9 hours ago, Steamdrivenandy said:

 

If you're going to use the 85% recommendation then measuring the actual loaded weight of the vehicle at any one time won't give you the kerbweight, it will be the actual weight, which the 85% wasn't designed to use. I would say look at the manufacturer's towing limit and get a van with an MTPLM 200kg below that figure for a new tower and 100kg below it if you're experienced. 

 

I'll use the late departed Yeti as an example:

 

1.2 Petrol Kerbweight between 1265kg and 1285kg, so say 85% = 1084kg. Towing Limit is 1200kg. I'd go for a van 1000kg MTPLM for a newbie 1100kg for experienced.

 

2.0 110PS Diesel Kerbweight 1377kg, 85% = 1170kg. Towing Limit 1500kg. I'd opt for 1300kg MTPLM for someone new to towing and 1400kg for someone experienced.

 

At the top of the range the 2 litre 150PS 4x4 Diesel Kerbweight 1500kg, 85% = 1275kg. Towing Limit is 2100kg. I'd go for 1900kg as a newbie and 2000kg when experienced. 

 

Again, if you're going to use the 85% don't get hung up on identifying the actual kerbweight for your model, down to the nth degree because,taking the first Yeti mentioned above, nobody will ever notice the difference between 85% of 1265kg (1075kg) and 85% of 1285kg (1092kg). So if the maker gives a range of kerbweights, opt for the middle and use 85% of that, it will be near enough for your purposes.

Thanks. Our tow car will be a Estate Mercedes E class 4 matic. I am trying to get the info from dealer off the vin and tow plates. The info generic so far - Kerb 1780.Max Tow 2100.

Link to comment
Share on other sites

3 hours ago, Steamdrivenandy said:

 

Lutz has mentioned that on a number of occasions but IIRC the additional parameters weren't involved in determining the stability of a towed caravan. They were things like strength of towbar attachment to body structure, braking capability, overheating of transmission, cooling of the engine.

After 40 years in vehicle engineering development and type approval testing I can also say that vehicle towing capacity is not based on such a simple test. 

Link to comment
Share on other sites

46 minutes ago, Ern said:

After 40 years in vehicle engineering development and type approval testing I can also say that vehicle towing capacity is not based on such a simple test. 

 

Thanks for the input Ern, it's always good when folks with real experience provide an input!

 

 

2018 Volvo V90 and 2018 Swift Sprite Quattro EB

Link to comment
Share on other sites

  • Martin locked this topic
Guest
This topic is now closed to further replies.
 Share


×
×
  • Create New...