flyboyprowler Posted January 25, 2014 Share Posted January 25, 2014 I noted the "new tyre blowout" post and have a variation question on this theme. The owners manual for my Voyageur recommends tyre pressures significantly different to the Continental tyre recommended pressures when related to axle loadings. Even at max axle loadings, the Conti pressures are lower than the manufacturers recommendation. Can anyone tell me why? Continental have been really helpful, but don't have an answer to the problem. I have also contacted the manufacturer (Pilote) but have had no reply. Any thoughts much appreciated, as this could be a safety issue. *-) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 26, 2014 Share Posted January 26, 2014 If you want useful feedback, you'll need to provide more information. 1: Exact details of the Continental tyres (eg. Vanco-Camper 225/75 R16CP 116R) 2: The tyre-pressures recommended in your Le Voyageur's Owners Manual. 3: Your Le Voyageur's maximum permissible axle-loadings (front & rear). It would also be helpful to know your motorhome's Le Voyageur model and year of manufacture. Link to comment Share on other sites More sharing options...
flyboyprowler Posted January 26, 2014 Author Share Posted January 26, 2014 Thanks for the reply, I will pass the figures when I can get to the van. However, I was just interested to know if there is a reason why seemingly all van recommended pressures seem to be higher than the tyre manufacturers recommendation for equivalent weight. (?) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 27, 2014 Share Posted January 27, 2014 Ordinary 'white van' tyres have a "C" letter after their wheel-diameter indicator to indicate the type of vehicle to which the tyres are designed to be fitted ("C"=Camionette=light truck.) For example - Continental Vanco-2 215/70 R 15 C 109/107S. When a motorhome is fitted from new with this type of tyre, the recommended tyre inflation-pressures given in the motorhome manufacturer's handbook will usually (but not always) match the pressures necessary for the maximum axle-loadings defined by the maker of the base-vehicle on which the motorhome has been built. However, many motorhomes are fitted from new with 'campervan' tyres, identified by "CP" after their wheel-diameter indicator. ("CP"=Camping Pneu=camping-car tyre.) For example - Continental Vanco-Camper 215/70 R 15 CP 109R. In such cases it's commonplace (though not universal) for the recommended tyre inflation-pressures given in the motorhome manufacturer's handbook to pretty much ignore the vehicle's maximum axle-loadings defined by the maker of the base-vehicle on which the motorhome has been built, and for much higher pressures (eg. 80psi for front and rear tyres) to be specified. There's a long and involved history to this policy, but it boils down to the contention (based on roaside inspections) that a significant percentage of motorhomes are driven with their axle-loadings at (and often beyond) their maxima. This has resulted in certain tyre manufacturers (currently Continental, Michelin and Pirelli) marketing 'ruggedised' "CP" tyres (Vanco-Camper, Agilis Camping, Chrono-Camper) and, to cope with the potentially high axle-loadings, these tyres need to be inflated to significantly higher pressures than equivalent size "C"-marked tyres. Tyre pressures recommended in a motorhome's handbook will usually repeat the pressures recommended by the manufacturer of the base-vehicle on which the motorhome has been built. In turn, the manufacturer of the base-vehicle will recommend tyre pressures based on information provided by the manufacturer of the tyres. If a tyre manufacturer provides high 'one pressure fits all' recommendations (as tends to happen with "CP"-type tyres) those pressure data are likely to end up in a motorhome's handbook. Provided that the tyre pressures recommended in a new motorhome's handbook are not too low for the vehicle's maximum axle-loadings, nor too high for the type of tyre fitted to the vehicle, they must be considered 'safe'. There have been instances where incorrect tyre pressures have been recommended (by Ford in the case of my Hobby motorhome) and I know that Michelin's Technical Data guide has contained inaccuracies in the past, but it's often difficult to spot questionable data. Without all the information I suggested you provide, it's impossible to guess whether your LeVoyageur handbook's advice on tyre pressures is actually wrong or just follows common practice. Link to comment Share on other sites More sharing options...
flyboyprowler Posted January 27, 2014 Author Share Posted January 27, 2014 Thank you so much Derek, for the comprehensive reply, which does answer my question. I will confirm the figures, but I am sure your explanation gives the answer. Many thanks. Link to comment Share on other sites More sharing options...
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