Ridgewoodwoody Posted March 4, 2022 Share Posted March 4, 2022 We have a 2019 Elddis Majestic 120. It's been suggested that adjusting the tyre pressures from those recommended by Peugeot for the basic Boxer vehicle could improve the ride. I gather that if you supply the tyre manufacturer, in my case Continental, with the two axle weights they would tell you the optimum tyre pressures. So yesterday I took it to the local weigh bridge yesterday,. According to the Elddis the unladen weight of the Majestic is 2593 kg. The reading from the weigh bridge with the two of us in the cab and our usual great on board was 1970 kg. I asked the chap if he would give me separate readings for the front and rear axles which gave readings of 980kg for the front and 290 kg for the rear. These readings have left me wondering how accurate the weighbridge was and I'm no nearer my objective. Any thoughts? Link to comment Share on other sites More sharing options...
Keithl Posted March 4, 2022 Share Posted March 4, 2022 Those weights are so inaccurate they are a joke! And they don't even add up! Find another weighbridge then go back to the first and ask for your money back. Keith. Link to comment Share on other sites More sharing options...
mtravel Posted March 4, 2022 Share Posted March 4, 2022 What do you mean by "improve the ride" ? Comfort or something else ? In all the campers that I owned, the manufacturer affixed a label with the recommended pressures. Most of the time they coincided or were very similar to those suggested by the manufacturer of the base vehicle for the fully laden mass. Because in the vast majority of cases a camper travels close to it. Does yours not have this label ? Link to comment Share on other sites More sharing options...
Tracker Posted March 4, 2022 Share Posted March 4, 2022 Back in the day when we were all, including van and tyre makers, less obsessed with legalities and 'recommendations', it was common for many of us to experiment with tyre pressures to get a more comfortable ride. At that time Michelin in particular were very helpful with their technical findings, always with the caveat that whatever the owner did was the owner's responsibilty if he deviated from the 'reccommended' pressures and tyre sizes. On that basis I made many of my own experiments over a set test route encompassing all sorts of roads and surfaces to decide my own tyre pressures and that worked for me for a lot of years and a lot of miles on many vans under many road and weather conditions, with minor alterations according to weight and body overhang. The greater the body size the harder the rear tyres needed to be to counteract inertia on changing direction swiftly when required. These days it is a different world with rules and regulations and manufacturing tolerances seemingly less generous so be very careful before you do anything to offend your insurers or any police or DVLA roadside spot checks you might encounter either random or post crash. There used to be websites that showed weight : tyre pressure : tyre sizes, including some tyre makers websites, but I have not looked for many years to discover what, if any, still exist. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 4, 2022 Share Posted March 4, 2022 This link provides relevant specification details for "Majestic" motorhomes including the 120 model https://nz.marquisleisure.co.uk/motorhomes/new/elddis-majestic-accordo/specification MAJESTIC 120 Maximum Technically Permissible Laden Mass (MTPLM) =- 3300kg Mass in running order (MIRO) = 2607kg Maximum front axle weight = 1750kg Maximum rear axle weight = 1900kg The tyre specification is 215/70 R15 CP and - as is the norm when CP-marked ('camping pneu') tyres are fitted - the advised tyre pressures are 72psi (front tyres) and 79psi (rear tyres). The Majestic 120 is a small 2-berth coachbuilt model and the likelihood is minimal that it will be operated anywhere near its 3300kg MTPLM or axle-load maxima. Consequently, using the 72psi/79psi pressures will undoubtedly result in a firm ride quality (probably a VERY firm ride quality). Axle load to tyre pressure data for Continental tyres is readily available online, so Alistair would not necessarily need to contact Continental himself. https://blobs.continental-tires.com/www8/servlet/blob/376746/e7bc88056a2e824d499c056ec3266193/download-technical-databook-data.pdf But the first thing to do is to get accurate (and credible) weight measurements for the motorhome and the weighbridge values he was given are (as Keith has said) clearly wrong. There's plenty of online advice on motorhome weights, payload and having the vehicle weighed. (example here) https://www.outandaboutlive.co.uk/motorhomes/articles/practical-advice/motorhome-weight-and-payload-a-beginners-guide and a GOOGLE-search on "weighing motorhome" will retrieve lots more stuff. I'm guessing that Alistair's Peugeot Boxer-based motorhome has a Tyre Pressure Monitoring System (TPMS). If that's the case, it's likely that the TPMS will have been matched to the 72psi/79psi front/rear tyre pressures mentioned above and - if those pressures are reduced significantly - the TPMS will issue warning alarms. Reducing high TPMS-set pressures has been discussed many times on motorhome forums, and will probably continue to do so now that Fiat Ducatos have TPMS as standard. These forum threads may be worth reading https://www.motorhomefun.co.uk/forum/threads/peugeot-boxer-tyre-pressure-monitoring-system.211938/ https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Tyre-pressure-monitors-again/46926/ Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 8, 2022 Share Posted March 8, 2022 Ridgewoodwoody - 2022-03-04 9:08 AM We have a 2019 Elddis Majestic 120. It's been suggested that adjusting the tyre pressures from those recommended by Peugeot for the basic Boxer vehicle could improve the ride. I gather that if you supply the tyre manufacturer, in my case Continental, with the two axle weights they would tell you the optimum tyre pressures. So yesterday I took it to the local weigh bridge yesterday,. According to the Elddis the unladen weight of the Majestic is 2593 kg. The reading from the weigh bridge with the two of us in the cab and our usual great on board was 1970 kg. I asked the chap if he would give me separate readings for the front and rear axles which gave readings of 980kg for the front and 290 kg for the rear. These readings have left me wondering how accurate the weighbridge was and I'm no nearer my objective. Any thoughts? Apart from the above comments, I would add that there is little point in going to a weighbridge unless you know exactly the load state of the van. For tyre pressures to reduce an overly firm ride when inflated to the standard, recommended, pressures for the van, it is essential to take the van, fully laden (meaning with everything, including food, clothing, fresh water, camping gear, electrical hook up, books, toys, pets, all occupants etc. etc.) so that the van is at the maximum weight it would be likely to reach when in use on the road. To get the individual axle loads the best approach (bearing in mine weighbridges are primarily intended to weigh commercial HGVs) is to first place the van on the platform and get its laden weight, and then run just the front wheels slightly off the platform (to leave rear wheels as close as possible to the centre of the platform), and then get the axle load for the rear. Front axle then = all up laden weight - rear axle laden weight. Bearing in mind the permissible tolerances of the weighbridge, you'd be very lucky to get a figure for the all up laden weight to equal the individual axle weights. You'd probably be better off going to a so-called "heavyside" builders merchant (i.e. one which handles bulk goods *(sand, gravel, etc), or scrap yards, since their weighbridges are used for calculating the value of loose materials delivered/collected in bulk and charged by the tonne. These machines are periodically subjected to accuracy tests by local Weights and Measures inspectors, who should hold the record of when the weighbridge was last tested. Electronic weighbridges tend to be more accurate with light loads, such as motorhome axles, that mechanical weighbridges. The one you used was either in the hands of an incompetent operator, or is in urgent need of a W&M test visit! I'd be inclined to contact W&M, report your experience, and see if they can direct you to a recently calibrated local machine. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 8, 2022 Share Posted March 8, 2022 Just out of interest I looked at Continental load-to-pressure data for their 215/70 R15CP tyre. Based on the Majestic 120 maximum axle load information I gave in my posting above, the inflation pressure for a front-axle loading of 1750kg would be around 56psi and for a rear-axle loading of 1900kg around 72psi. The Elddis advised pressures are apparently 72psi (front axle) and 79psi (rear axle) - the pressures usually advised by a motorhome manufacturer for vehicles factory-fitted with 215/70 R15CP tyres. While reducing the rear tyre pressures from 79psi to 72psi might be tolerated by a TPMS system (and should help a bit regarding a harsh ride quality), it's probable that reducing the front tyre pressures from 72psi to 56psi would provoke a TPMS system into issuing warning alarms. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.