paddiesdad Posted July 7, 2011 Share Posted July 7, 2011 Hello all, I have a 1999 Hymer van on a Fiat 2.8td base. All's well except the ride, which is most uncomfortable especially for my wife who suffers from arthritis. I fitted Dunlop air suspension on the rear axle last year without much improvement to the ride. I contacted the suspension supplier, Marcle Leisure (who I've had excellent service from) and they said either reduce the pressure in the air ride to 20psi or lower, or take out one of the 2 leaf springs in the rear set up. I'm worried that if I reduce the air pressure, we'll be rolling round the bends and roundabouts again as we used to, and I'm not too sure about removing a leaf spring. Can anyone advise on the way forward? If you have a motorhome that glides over the pot holes, speed bumps or lumps that plague us on our roads, can you let me know. I'd consider changing the van if there was a perfect solution! Cheers, Peter. :-| Link to comment Share on other sites More sharing options...
Robinhood Posted July 7, 2011 Share Posted July 7, 2011 Welcome. The Ducato isn't renowned for its compliant ride, but the first question usually asked in these circumstances is "what tyre pressures are you running at?". Converters/manufacturers habitually quote tyre pressures that are at the absolute maximum of the range, and if you haven't adjusted them to your normal running axle weights, this can contribute greatly to the bumpiness of the ride. On tyre-manufacturer's advice, on a number of Ducatos, I have (by quite an amount) reduced pressures to those recommended by them against the actual in-use axle weights, with a significant improvement in ride. Have you taken any steps in relation to tyre pressures, or are you running at the vehicle manufacturers quoted pressures? Link to comment Share on other sites More sharing options...
Guest pelmetman Posted July 7, 2011 Share Posted July 7, 2011 Just a thought:D......How old are your tyres?.......I ask as last year I replaced our 10 year old Hankooks due to age, with the same make and I was surprised just how much the ride had improved, maybe the rubber goes stiff with age;-) Link to comment Share on other sites More sharing options...
Guest Tracker Posted July 7, 2011 Share Posted July 7, 2011 Hi Peter and welcome to the madhouse. I suspect that your tyre pressures may be needlessly high? If you can tell us what tyre pressures the door frame label suggets and what you run the tyres at together with the tyre ratings and size plus the van's front and rear axle weights and maximum gross weight someone will probably have some experience of your situation. The Boxer / Ducato base vehicles never were the best riding of vans but the trade off is allegedly better stability - but I'm not convinced! Some tyre manufacturers - but not all - will also be able to advise you on suggested tyre pressures if you supply them with the above information. If you want a smoother riding van either a Merc or VW are alleged to be the softest riding although a Boxer / Ducato with the Alko chassis runs them close and costs less. If all else fails you can get seats with their own suspension which might help although I have no personal experience of these. Link to comment Share on other sites More sharing options...
thebishbus Posted July 7, 2011 Share Posted July 7, 2011 Hi . You mention that you had rolling and a hard ride before you had air suspension fitted. Air suspension should give you the adjustment between hard and soft ride, depending on air pressure , I think not a good idea to remove a spring leaf. All I can think of is perhaps a spring shackle seized ( unlikely) or the the tyre pressures to high for the load you are carrying, or the tyres hardened with age. Brian B. Link to comment Share on other sites More sharing options...
Brian Kirby Posted July 8, 2011 Share Posted July 8, 2011 You may have the air rides a bit hard. There is no harm in experimenting within the pressure range suggested by the manufacturer. They seem to stipulate a minimum pressure below which the vehicle should not be run. What they mainly do is keep the tail taught on roundabouts etc. If inflated so that they lift the rear to the same level (relative to the ground) when fully laden, as it sits when unladen, it seems to give the best compromise (on ours) between ride comfort and ride control. However, bearing in mind that the original springs are still there, the ride improvement is inevitably limited. As others have said, tyres over-inflated relative to load give what many find a harsh ride. First step is to fully load the van as for a trip, with all passengers etc aboard, and take it to a weighbridge. Explain you want the all up load, plus the loads on each axle, and want the printed ticket. Usually, this will involve first weighing the whole van (A), then advancing so that the front wheels are just off the platform and weighing again (B). B is the load on the rear axle, and A-B is the load on the front axle. Check these against the VIN plate, to be sure both axles, and the van itself, are within their permitted limits. Then contact the technical advisory department of the manufacturer of your tyres, give them the full details of the make and model of the vehicle chassis, and of the tyres (type, size, section, speed and load ratings) and ask them what actual pressures they would advise. Then ask if they will confirm that in writing, if you e-mail them with the weighbridge data. An alternative, which will help to explain what is required, is to go here: http://tinyurl.com/ygj67lm and download the booklet about motorhome tyres. In it you will find information about the pressures relative to load for quite a few commonly fitted motorhome tyre sizes. It is worth getting, and keeping, the weighbridge ticket, and either the tyre manufacturer's recommended pressures, or the TyreSafe booklet, in the van, in case you are ever stopped at a VOSA (or other) roadside weight check, and the tyre pressures are queried. You will then have the evidence that you are using appropriate pressures. You should find this improves the ride, and you may find the handling improves as well. Hope this helps. Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted July 8, 2011 Share Posted July 8, 2011 ..unfortunately,you may find that the tyre manufacture covers their backside and just issues the max pressures anyway.. That's all that Michelin did,when we provided them with weights/axle loadings(..they stated 79psi for the rear!) ..I think other members have recently posted similar experiences after contacting tyre manufacturers.. (..Sorry,don't mean to derail this and turn it into just another "tyre pressure" thread! (lol) ) Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 8, 2011 Share Posted July 8, 2011 My experience with my last four vans came down to the wheelbase, our present van a LWB Ducato is like riding in a Rolls Royce compared to all previous three, none of which were LWB base versions. Our first of the four was a SWB coachbuilt with a ridiculous amount of rear overhang that was so uncomfortable to ride in we quickly sold it. In addition having recently changed the tyres from "camping" tyres to Kumho van tyres with obviously the same load and speed rating the ride improved further running at 60/65 psi, and saved me quite a few bob into the process. :-) Link to comment Share on other sites More sharing options...
Guest Peter James Posted July 8, 2011 Share Posted July 8, 2011 Michelin habitually quote 80psi for the rear of motorhomes - yes really. Apparently some study found many motorhomes overweight on the rear axle, so since then Michelin have always quoted maximum pressure. Their email to me states 50psi front 80psi rear, despite axle loadings about the same. I replied to them that their tyres have 76psi max marked on the side! Then they replied again 50psi all round Link to comment Share on other sites More sharing options...
Guest Peter James Posted July 8, 2011 Share Posted July 8, 2011 ........ Link to comment Share on other sites More sharing options...
Brian Kirby Posted July 8, 2011 Share Posted July 8, 2011 Brian Kirby - 2011-07-08 12:17 AM.............................An alternative, which will help to explain what is required, is to go here: http://tinyurl.com/ygj67lm and download the booklet about motorhome tyres. In it you will find information about the pressures relative to load for quite a few commonly fitted motorhome tyre sizes. .............................. Apologies for quoting me, but quicker than re-typing! :-D The booklet linked above is published under the name TyreSafe. The data in it comes from The British Tyre Manufacturer's Association (BTMA, use to be British Tyre and Rubber Manufacturer's Association). All the major tyre manufacturers on the UK market are BTMA members, and all subscribe to the published data. If you need information relative to a tyre size that is not listed in the booklet, quoting the data for the nearest equivalent when phoning for information, should bring them back on track. They are nervous about becoming liable for information they provide, where they know so few motorhomers actually get their vans, and the individual axles, weighed. That is why I suggest an exchange of e-mails rather than just a phone call. Even, if necessary (though no-one has yet reported this being requested), a copy of a weighbridge ticked. They can then, if they have to, prove what they were told, and what they said in response. Not, IMO, unreasonable. There is also a downloadable version of the Continental Technical Data Book on Continental.com. It is far more detailed, covers a much wider range of tyres and, among other things, also gives pressure for load tables. However, that data, obviously, is relevant only to Continental's specified tyre ranges. Similar information is doubtless available from other manufacturers in respect of their ranges. I have heard that the Pirelli Chrono van tyres tend to run smoother than others, but they seem little used in UK, no doubt to their generally higher cost, so little actual confirmation can be gained. Link to comment Share on other sites More sharing options...
Clive Posted July 8, 2011 Share Posted July 8, 2011 The Fiat chassis corners like it is on rails but a soft ride it is not. For a soft ride you should have bought a Merc. C. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 9, 2011 Share Posted July 9, 2011 paddiesdad - 2011-07-07 8:35 PM Hello all, I have a 1999 Hymer van on a Fiat 2.8td base. All's well except the ride, which is most uncomfortable especially for my wife who suffers from arthritis. I fitted Dunlop air suspension on the rear axle last year without much improvement to the ride. I contacted the suspension supplier, Marcle Leisure (who I've had excellent service from) and they said either reduce the pressure in the air ride to 20psi or lower, or take out one of the 2 leaf springs in the rear set up. I'm worried that if I reduce the air pressure, we'll be rolling round the bends and roundabouts again as we used to, and I'm not too sure about removing a leaf spring. Can anyone advise on the way forward? If you have a motorhome that glides over the pot holes, speed bumps or lumps that plague us on our roads, can you let me know. I'd consider changing the van if there was a perfect solution! Cheers, Peter. :-| If a motorhome rolls excessively when cornering (as many older models did), but its ride, road-holding, 'stance', etc. is otherwise OK, then it makes sense to address the roll characteristic specifically. The usual way of counteracting excessive roll is to fit anti-roll bars to the vehicle's suspension or, if anti-roll bars are already present, to fit beefier versions. See the following links http://www.accessoires-camping-car.net/acc-kit-bleu.html http://www.jsa.fr/produitsjsa However, playing around with anti-roll bars may not be straightforward nor cheap, so there's a tendency to fit 'air-assistance' (in your case Dunlop units) to the motorhome's rear suspension instead. Assuming that the air-assistance units do not replace existing spring-assisters (eg. chassis-to-leaf-spring 'bump-stops'), the motorhome's ride will be harder after air-assistance units have been installed. This is inevitable as, however low the pressure in the air-assistance bellows, it cannot be lower than zero, which was the pressure in the empty space that was originally between leaf-spring and chassis. Air-assistance units counteract roll by stiffening the motorhome's rear springing and a harder-than-before ride is a natural and unavoidable consequence. As has already been advised, if you want to optimise your Hymer's ride quality, you should first ensure that your motorhome's tyres are not over-inflated. You should then experiment with the pressure in the air-assistance bellows, reducing it until the level of roll during cornering becomes unacceptable and then increasing it until the ride becomes uncomfortable. (Marcle Leisure's suggestion that you might benefiit by removing a rear leaf-spring is very questionable and I'd seriously challenge their expertise in this respect.) If your Hymer's ride is still rough, then an inexpensive ploy that you might try to help your wife is to heavily pad her cab seat. I'm thinking in terms of a cut-down thick duvet that would insulate her body from more severe road shocks. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 9, 2011 Share Posted July 9, 2011 The bloke at Marcle leisure is extremely helpful, but I too doubt the wisdom of his suggestion. Perhaps look at the feasibility of a Bostram seat. Link to comment Share on other sites More sharing options...
tonyishuk Posted July 10, 2011 Share Posted July 10, 2011 I was surprised to look under a couple of moderately expensive (£40-50 thousand) X250 british motorhomes on Fiat bases and see leaf springing. For similar cost it seems that a number of continental motorhomes have Alko torsion bar suspension. I would think the latter would ride and handle better. or am I misguided ? Rgds Link to comment Share on other sites More sharing options...
crinklystarfish Posted July 11, 2011 Share Posted July 11, 2011 The old 2.8JTD wasn't a bad ride for a commercial van and you've already explored some decent options.I'm guessing, reading your requirements, that no amount of tyre / suspension fine tuning is going to bring the results you want. Have a look here: http://www.jennings-seats.co.uk/ and talk to the fellows there. There will be a bit of faffing matching base to swivel and it might not even be possible. However, if comfort is your absolute priority, it's probably going to be the only solution that will meet your needs. Link to comment Share on other sites More sharing options...
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