I'm so confused... My first motorhome, 1994 Ducato 14, Knaus traveller 630. I must have read thirty different forum threads, practical whatever, this and that user groups and I still cannot get close to being able to confidently take my van to an air line.... There are warnings about rubber valve stems, sidewall failure, prosecution and general catastrophe...
Where can I go to get a realistic practical answer?
I don't have an original owners handbook for the Motorhome converter or for the Ducato.
Now I'm being warned about MAM or MTPLM, people saying I need to only carry one passenger, empty water tanks, and don't carry food...
What's the point if it causes all this anxiety?

A Knaus owners manual would be a great help (cash waiting). Advice from a seasoned owner would be invaluable.
Instructions to go to a weighbridge and contact tyre manufactures I have plenty of, but it all seems a bit extreme for something which should be a pleasure.

Hi trakhat. Welcome to the forum. It can be very confusing with the tyre pressures and you will get lots of different answers as you have found out.

The reason for weighing the van in loaded ready to holiday mode is two fold, this should be by weighing each axle separately then the whole van.

1 To see what you axle loadings are and how much payload you have left.

2 The axle loadings will give you the figure to ask the tyre manufacture what their recommended pressures should be for that axle weight.

Some people like to use only camping car tyres as they supposedly have thicker sidewalls to withstand long parked up times. Some countries have rules on tyres in winter for example.

Motor home tyres are usually run at higher pressures then is recommended for rubber valves and bolt in metal ones might be needed.

I think there are some manuals for the Ducato base on here, perhaps someone else can help with that.

Most of the manuals for the habitation side for fridges, heaters and toilets ect can be obtained from the individual items manufactures web sites.


Hope this Helps. Just keep asking questions. Mike

Thanks Mike, I suppose I am trying to avoid chasing tyre manufacturers etc. I have most of habitation type manuals it's the chassis cab and stuff I don't have - and of course anything specific which needs to be changed due to motorhome builder.
Bob.

Hi, Don't waste your time looking for a workshop manual. I've been looking for 8+ years. As for tyre pressures, weighbridge is the only answer. I did mine and then adjusted the pressures from what was recommended to what was comfortable to drive. +/- a couple of psi. Any questions you have in the future, just post on the forum and someone will know the answer or tell you where to search. All the Best, Ian.

Best method for deciding on pressure.
Weigh front and rear axles in vehicle loaded state. Divide by 2 for individual tyre loading.
Check sidewall on tyres and find the specs. You will find something like MAX load 990kg @ 75psi.
Use your loading weights from the weighbridge as a percentage of the maximum weight allowed. ie. If your weight per front wheel was 750kg, you would do the sum - 750/990X75 = 56.8psi Do the same for rear.
That will give you pressures as recommended by Michelin and others.

Ian.

Hi Trakhat,
I've always run my tyres at 10psi lower than maximum stated tyre pressure and had no issues at all. (60 psi on Michelin Agilis ,max ix 70,with 3.5t GVM, 2005 Sunliner motorhome)
Hope this helps

That's just guesswork Pedro with no knowledge of loads being carried. The way I posted above is the only CORRECT method.

Ian.

Maybe not the correct or scientific method but I use the "seat of the pants" method. Started off with 80psi, as recommended on the tyre plate. The ride was very hard and bouncy. Dropped both ends by 5psi then another 5 psi to 70psi and my seat felt good. Used that pressure for the last 28,000 klms with no issues. Cheers,

55 to 60 psi for a 3.5 ton van with vanco camping tyres ???