Jump to content

Payload and Towing Capacity


StuartO

Recommended Posts

We all now the extent to which motorhome bodies rest heavily on their van chassis, and some of us have little interest in towing capacity - but the two are not unconnected and for some of us, including me, both are important. It can be quite difficult to end up with a payload and a towing capacity which are adequate for your purpose.

 

For example I have been looking at the Hymer S Class of 2001-2006, whch were staggeringly expensive in their day but are now becoming more affordable. although perhaps not yet to everyone.

 

These mighty beasts were wide and tall and came in various lengths and layouts but they all had a decent published payload, in most cases over 1,000kg, often 1,200 or 1,300kg. That was is a sense their claim to fame. How, you might ask yourself, could that not be enough fr anyone?

 

The answer is to want to tow a car on a trailer, as we do, which weighs a total of nearly 1,400 kg. If you choose a manul gearbox version that's fine because this series of S Class had a towing capacity of 2,000 kg on top of their payload of up to 1,300 kg.

 

However if you wanted to have an automatic gearbox, it is a very different story indeed and the towing capacity at the full chassis loading drops dramatically to only 750kg and any more you might want to tow, up to a maximum of 1,500kg, has to be deducted, kg for kg, from the payload. In order to tow 1,400kg, I would therefore need to sacrifice 650kg of payload.

 

But these big Hymers were heavy to start with and commonly adorned with heavy accessories which you wouldnl expect to count against payload, like three heavy leisure batteries. Secondary air conditioning was common too, also a heavy item. The water tank holds 200 litres, so that's another 200kg gone, Some had an extra large fuel tank for range, with at least 100kg of fuel, sometimes more.

 

And then there's your difficult-not-to-take items like gas bottles, an awning, levelling ramps, a TV (or two in MHs this size) not to mention a tow bar, a porch awning, anti-skid mats for getting off soft ground, a BBQ, etc etc. And then there is the clothing, food, toiletries etc. There wouldn't be 650kg of payload left for me to sacrifice. With an automatic gearbox I certainly could not tow our car on a trailer.

 

So why did Hymer restrict the towing capacity of this S Class so drastically if the vehicle was fitted withautomatic transmission? This was a popular option, perhaos 90% or more of those sold were with an automatic gearbox.

 

It must be a power train limitation which is doing this, I guessed, something to do with gearbox cooling, which once upon a time was a performance limitation of all automatics. After all apart from the gearbox, the manual and automatic versions were identical: same chassis, same bodywork, even the different gear levers weighed about the same.

 

But it can't be as simple as that because on checking with SVTech, the upgrade specialtists, the Mercedes Sprinter 616 chassis, which was the base of the bigger S Class, had the same 2,000 kg towing capacity for manual and automatic gearbox - so the towing limitation on the S Class automatics was imposed by Hymer rather than Mercedes Benz.

 

So I have asked Hymer to explain, and also to advise about whether any modifcations can be made to increase the towing capacity. They welcome technical enquiries and have always responded fairly quickly in the past. I will add another post when I get a reply.

 

In the meantime what's your theory? Why chop 1,250kg off the towing capacity of the automatic version when the same Hymer body goes on to the same Sprinter chassis. Mercedes Benz didn't do that with its heavy Sprinter van so why did Hymer with its motorhome?

Link to comment
Share on other sites

The Base Vehice is a Mercedes Benz Sprinter 616, plated by MB at 5990kg gross with an additional 2000 kg towing capacity, whether manual or automatic gearbox, Gross Train Weight is therefore 7990 kg.

 

Hymer plate the manual gearbox version of their S820/S830 the same but for an automatic the GVW stays at 5990kg but the GTW is only 6740 kg, so a towing capacity at full load of only 750 kg.

Link to comment
Share on other sites

Some years ago I looked into this situation, my understanding it was the gearbox that was an issue in fact several dealers warned me off buying the early s820 which is recognisable by the rear wheels being half covered in.

 

I bought a s700 which is on the 416 chassis as a towing weight of 2000kg and a payload over 1000kg. With auto box. Had the van for approx 6 years now and very pleased, be about £140.000.00 to replace it today, crazy!,

Link to comment
Share on other sites

Towing a car wasn't as popular ten years ago when these S Class were being built but even so it seems bizarre that Hymer restricted the towing capacity of the automatic so drastically when Mercedes Benz were happy for the automatic chassis to tow the same as the manual. If it was because of inadequate airflow for coolong the auto gearbox you'd think they could have solved that problem constructively. Once upon a time it was common practice to install an additional oil cooler to aid gearbox performance.

 

Hymer are nothing if not German and logical, so there will be a reason. I just can't think what it could be.

Link to comment
Share on other sites

StuartO - 2014-10-13 9:25 AM

 

If it was because of inadequate airflow for coolong the auto gearbox you'd think they could have solved that problem constructively. Once upon a time it was common practice to install an additional oil cooler to aid gearbox performance.

 

 

The Hymer documentation of 2004 supports your statement on the limitation of GTW with the auto option.

 

I thought this vintage of auto Sprinter was fitted with the Sprintshift "robotised manual" gearbox (similar to the Fiat Comfortmatic), and if so, I doubt that oil cooling would be the problem (as it might be on a "slush" box).

 

Indeed, the MB option at that time was the Sprintshift, (and this was fitted as standard to the S650 (with no reduction in GTW shown) BUT it was not available for the S740 or S820.

 

If an auto box was required for these, an expensive option of a Wandler (slush-box?) auto was available (see below).

 

I suspect this difference may account for some of the 'discrepancy'.

 

1104829428_HymerS-Class.thumb.JPG.9bc345816eb12aff800ecbb9166de895.JPG

Link to comment
Share on other sites

This is an extract from the 2006 Hymer Price List/Techgnical Details,which shows that the Sprint Shift gearbox was not available for the 616 chassis, used on the S830, but there is a mention of a "Converter Transmission" for the 616, which was presumably the different type of auromatic transmission for the heavier vehicles. 2006 was the final year for this series of S Class.

 

It is this "Converter" gearbox which I understand from SVTech is listed in Mercedes Benz documentation for the chassis type as capable of towing 2000 kg in addition to full payload, same as the manual gearbiox, which Hymer resticted in its literature to towing only 750kg (or with less payload 1,500 kg). That's the puzzle.

 

Apart from the English translation and the price difference when quoted in GBP, the options for an auto gearbox were unchanged from 2004 and earlier. Presumably "Converter" refers to a torque-converter type gearbox. Torque converters are used for very heavy duty appliations (like passenger buses) so if Mercedes Benz reckoned that this chassis and gearbox could cope with full load plus towing 2,000 kg, why did Hymer decide otherwise?

 

Has anyone heard of automatic gearbox failures in this series of S Class? It's not something that I have ever heard of. The only theory I can come uo with is that Hymer found it necessary to remove some gearbox cooling provision, in order to fit everything into the S Class body, but I doubt if that would be a compelling reason.

513232469_SClassPriceExtract2006.thumb.jpg.7ef8029d7ede555cb2ce8fd420b70f0c.jpg

Link to comment
Share on other sites

I rang a Mercedes commercial dealer today and they put me on to a technical guy at Milton Keynes, presumably Mercedes UK HQ. Very helpful chap. He explained that it could be the particular combination of power train components (which can vary) which limit the towing capacity so I have given him the vehicle's VIN number and he is going to check.

 

It's beginning to sound like Hymer might have opted for a downgraded towing capacity with the auto box for other performance reasons, such as a different final drive ratio, optimised for non-towing reasons. He's going to investigate and let me know.

Link to comment
Share on other sites

The Mercedes Benz 616 CDI chassis/cowl which Hymer used for its bigger S Class motorhomes from 2000 to 2006 was only sold by MB as either a chassis/cab, for use as a pick-up or tipper truck, or chassis/cowl, for buses and motorhomes. It was not sold for use as a van.

 

This is the cab/chassis version, which doesn't immediately grab you as the basis of a motorhome!

616chassis.jpg.53bdf34a83fe166ac6e7c3e898796689.jpg

Link to comment
Share on other sites

  • 3 weeks later...

I bumped this Thread to pass on the final outcome of my enquiries of Hymer and Mercedes to establish why the automatic versions of the Hymer S Class of 2001-2006 were so limited in towing capacity. The manual gearbox version could tow 2000 kg in addition to a GVW of 5990 kg, so a Gross Train Weight of 7990 kg but the automatic is limited to a Gross Train Weight of 6740 kg, so towing anything over 750 kg has to come off the GVW pound for pound.

 

The answer is a drive train limitation and upgrading would require a change of gearbox and back axle. Not economically viable.

 

 

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...