This problem could affect all Motorhomers as the maximum pressure for rubber valves is 65 to 69 psi. Below is an extract from Michelin which should be self explanatory. The problem however is not restricted to Michelin or Swift but anyone with rubber tyre valves.
According to Michelin, I quote: "Product 'XC Camping' is able to run at inflation pressure levels up to 5.5 bars (80 psi). The pressure limit for a rubber stemmed valve design is listed at 4.5 bars (65 psi) to 4.75 bars (69 psi) depending upon the precise dimensions of the valve stem concerned (diameter, length etc.) When using tubeless tyre fitments with a potential working pressure in excess of 4.5 bars (65 psi) to 4.75 bars (69 psi), therefore, metal clamp-in type tubeless valve stems must be employed. The above limitations, regarding rubber stemmed valve designs, are listed within the ETRTO (European Tyre & Rim Technical Organisation) 'Standards Manual': ETRTO (European Tyre & rim Technical Organisation) Tel: (Belgium) 322 344 4059 Fax: (Belgium) 322 344 1234 Web: http://www.etrto.org/ Email: info@etrto.org" Yours sincerely Michelin Tyre Public Limited Company
With reference to Whistling Gypsy's comment that the pressure given on the B doorpillar being ok for commercial vehicles but not necessarily for motorcaravans of the same GVW, the tyre pressures recommended by the tyre manufacturers are based solely on the weight carried by the tyre. The pressure is the same irrespective of the use to which the vehicle is put. The only variations are that Michelin recommend an extra 5psi for the driven wheels and also a small variation for extremes of temperature. The recommended pressures are based on an ambient temperature of 17ºC. At 0ºC the pressure should be 5psi less, for example.
BrianR, i am not quite sure if your remarks are exactly right or if the info Swift gave me is right, the reason i question it is that Swift recommended 4bar front/4.5bar rear and as the van is front wheel drive it does not match your info from Michelin.
When i asked for info on the camping car tyres from my tyre dealer i was told the walls of the CCTs are strengthened to compensate for the body roll of a m/h which i assume is inherent of the design of such vehicles.
These are facts supplied by other people so i cannot vouch for the validity of their comments
My statement was did not contain any specific recommendaed tyre pressures, so I am confused as to why you say it is contrary to the Swift recommendation specific to your vehicle. The B pillar tyre pressures are those recommended by the manufacturer for the vehicle when loaded to the maximum permitted weight for each axle and with the tyres they have fitted. Normally the rear axle has a higher permitted weight than the front, hence the difference. The Swift recommendation would be based on the tyres fitted to the conversion, which may be the same or different. The recommended tyre pressures for a "Camper" type tyre are only correct for that tyre and take into account its construction. They are correct whatever type of vehicle it is used on. If you contact Michelin with the details of your tyres, they will tell you the correct pressures for a couple of typical weights at the high and low end of the scale and suggest that you interpolate from these the pressures correct for your vehicle. They will also recommend that you add 5psi to these weights for the driven axle. To know what these weights are you need to load up your 'van with everything you take on a trip, including fuel and water, and get it weighed at a weighbridge, each axle separately. then you will know that your 'van is safe with regard to tyre pressures. I hope this helps - for historic reasons I am a bit obssesed with getting tyre pressures right.
My new valves arrived yesterday, as promised by Swift. Looking at them gives me a lot more confidence, they are substantial bit of kit compared to the rubber ones.
Just have to contact an ATS fitter now, they do the 'bis', fill in a from and I return form and old rubber valves to Tyre Line Ltd (for evaluation).
so confusing , we have not long had our first motor home, on the door lable it recommends 5.5 bar 78psi for front and back i have just tested the pressures and all 4 wheels are 69psi i must say that i have not tested them since we picked it up in nov we have a bessacarr e725 upgrade to 4000kg can anyone recommend what pressure i should put in the tyers
thanks martin
I have had the same problem. A tyre went flat on the M6 with no obvious reason. A week or two later a had a flat on the drive - ATS diagnosed rubber valve leakage and replaced it with a plastic one for £3.95. I suggested at the time that all the others should be looked at, but the young fitter said they were OK. Two weeks later another different tyre went down - this had a rubber valve also - you could see the valve was swollen. This was again replaced for £3.95 (this time a high pressure version). All tyres are now OK - its worth checking. Andy
Vehicle Details
Reference : R/2007/150
Manufacturer Ref :
Make: FIAT
Model : Ducato (250) with steel wheels
Launch Date : 23/11/2007
Numbers Involved : 368
Build Start Date : 01/08/2007
Build End Date : 30/09/2007
Recall Details
Concern : TYRE VALVE MAY BREAK CAUSING RAPID DEFLATION (STEEL WHEELS)
Description : It has been identified that due to manufacture from an incorrect material, the tyre inflation valve may break. Should this occur, rapid deflation of the tyre, and possible vehicle instability would occur.
Remedial Action : Recalled vehicles will have the tyre inflation valve replaced on all steel wheels including the spare.
Vehicle Id : ZFA25000001268314 to ZFA25000001292389
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