Brambles Posted October 4, 2012 Share Posted October 4, 2012 George, it works by having a tube embedded in the side wall of the tyre next to the bead. When the tyre rolls along the road the tube is compressed and as this compression moves around the tyre, and hence the tube, it pumps air into the tyre controlled by a preset pressure sensor and valve. Good Year are plannng an extensive fleet proving trial on HGVs in 2013. Link to comment Share on other sites More sharing options...
Tracker Posted October 4, 2012 Author Share Posted October 4, 2012 Brambles - 2012-10-04 7:02 PM George, it works by having a tube embedded in the side wall of the tyre next to the bead. When the tyre rolls along the road the tube is compressed and as this compression moves around the tyre, and hence the tube, it pumps air into the tyre controlled by a preset pressure sensor and valve. Good Year are plannng an extensive fleet proving trial on HGVs in 2013. As there is only so much air in a tyre at any given time, that sounds suspiciously like perpetual motion - wish I'd thought of it!!! Link to comment Share on other sites More sharing options...
George Collings Posted October 4, 2012 Share Posted October 4, 2012 Thanks Brambles, One end open to the atmosphere and a system of one way valves in the bead. Neat. Its rather like the sort of pumps you see used to circulate blood in open heart surgery and other medical applications. That type are usually in the form of a coiled hose with a roller inside the coil compressing the hose and driving the fluid in front of the roller. My guess is the flow is free of the pulsations delivered by many pumps. Now Goodyear need toto refine the system so inflation pressure varies according to tyre loading eliminating repetitive threads on the subject on this forum. Link to comment Share on other sites More sharing options...
Brambles Posted October 5, 2012 Share Posted October 5, 2012 Yes, exactly the same principle as using a peristaltic pump. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 5, 2012 Share Posted October 5, 2012 To avoid motorcaravanners having to agonise over the inflation-pressures they should use for their tyres, Michelin is developing a "SN" (Sans Air) tyre specifically aimed at the camping-car market. This YouTube video-clip demonstrates the concept and the motorhome version is currently being tested on US military vehicles. The motorhome tyre (provisionally called "Agilis Camping SN" by Michelin) will have an aggressive tread-pattern offering high levels of off-road grip (especially on wet grass) and, because the tyre acts rather like a tank's tracks when faced with an obstruction, ascending levelling-ramps should be a piece of cake in future. The expectation is that Agilis Camping SN will begin to be manufactutred in limited quantities in late-2013 at the massive Shanghai Michelin Warrior Tire factory. I understand that Fiat is particularly interested in the SN, with a view to including it as part of the motorhome package that will be made available when the X256 Ducato arrives next year. Link to comment Share on other sites More sharing options...
Tracker Posted October 5, 2012 Author Share Posted October 5, 2012 Maybe it is time for a radical rethink on tyres? Perhaps a rubber wheel to absorb noise vibration and shock, with a steel tyre to avoid bursting and punctures? Certainly it is perhaps time to move on from Mr Dunlop's excellent (at the time) idea of pneumatics and inflation? Link to comment Share on other sites More sharing options...
Brambles Posted October 5, 2012 Share Posted October 5, 2012 Brilliant idea Tracker, we could call it the 'steel belted radial tyre'. ;-) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 5, 2012 Share Posted October 5, 2012 Tracker - 2012-10-05 9:52 AM Maybe it is time for a radical rethink on tyres? Perhaps a rubber wheel to absorb noise vibration and shock, with a steel tyre to avoid bursting and punctures? Certainly it is perhaps time to move on from Mr Dunlop's excellent (at the time) idea of pneumatics and inflation? You'll see from the first video-clip that this is exactly what Michelin has been exploring - the practicality of a flexible non-metallic wheel with an air-less 'tyre' fused to it., with the wheel/tyre possibly even becoming a suspension component. Link to comment Share on other sites More sharing options...
Tracker Posted October 6, 2012 Author Share Posted October 6, 2012 Given that vehicle makers put stickers on each new vehicle to denote what they consider the optimum tyre pressures should be, it seems odd to me that when you ask different tyre makers to advise on specific pressures for specific weights and applications they not only differ greatly from what the manufacturer (Fiat/Peugeot) advise - even when at maximum load - they also tend to come up with different answers to each other. Over many years I have long believed that many car and van tyres are far too hard to give a decent ride when at the quoted figures, although this is not helped by vehicle makers pursuing 'sports' car handing and alleged economy at the expense of ride comfort with their suspension settings. In order for tyre makes to be able to be mixed within their specific types you would expect that tyres of each specific type and size would be made to a standardised format to ensure safe and predictable handing and braking when mixed with other makes of the same size which is legal, if not advisable. In which case should they all be singing from the same hymn sheet and referring to a standardised tyre pressure to weight chart? Link to comment Share on other sites More sharing options...
Brian Kirby Posted October 7, 2012 Share Posted October 7, 2012 Derek Uzzell - 2012-10-04 2:23 PM Brian Kirby has fitted VancoFourSeasons to the front wheels of his Hobby Van to help address concerns about the vehicle's grip-level, so he may be able to advise on their effectiveness. In principle, on a tread-pattern basis, VancoFourSeasons should be more suitable for motorhome usage than, say, Vanco, but I've no idea if it would be better than Michelin's Agilis....................... Yes. Got them from Camskill, who had stock at the time. Wet tarmac grip is better than the std Vancos, and for tyre size/spec inflation pressures identical. Very slight increase in noise on road, but hardly noticeable on most surfaces. Very pleased with overall performance, seem to have better traction on most surfaces, ride unchanged, handling in wet improved,and M+S rating means legal in Germany all year. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 8, 2012 Share Posted October 8, 2012 Brian Kirby - 2012-10-07 12:03 PM Derek Uzzell - 2012-10-04 2:23 PM Brian Kirby has fitted VancoFourSeasons to the front wheels of his Hobby Van to help address concerns about the vehicle's grip-level, so he may be able to advise on their effectiveness. In principle, on a tread-pattern basis, VancoFourSeasons should be more suitable for motorhome usage than, say, Vanco, but I've no idea if it would be better than Michelin's Agilis....................... Yes. Got them from Camskill, who had stock at the time. Wet tarmac grip is better than the std Vancos, and for tyre size/spec inflation pressures identical. Very slight increase in noise on road, but hardly noticeable on most surfaces. Very pleased with overall performance, seem to have better traction on most surfaces, ride unchanged, handling in wet improved,and M+S rating means legal in Germany all year. It would be worth knowing whether Continental would have recommended the Four Season tyre to Tracker if VancoCamper had been available in 225/70 R15 size. The results of a "Pro Mobil" comparative tyre-test are shown here http://www.motorcaravanning.com/vehicles/tyre_test.htm VancoFourSeason scored well, though It's perhaps worth pointing out that all the tyres being compared with Micheln's elderly XC Camping pattern were 10-ply-rated to provide the 'overload' capacity XC Camping was advertised as having. Although the Pro Mobil data are said to be from 2006, the original test was in 2002, so the VancoFourSeason pattern is now more than 10 years old. Continental's 2011/2012 Technical Databook suggests that (as with the Vanco and Vanco-2 patterns) VancoFourSeasons will continue to be made despite there now being a VancoFourSeason-2. However, the latter is offered in 16" wheel-diameter sizes only. Although VancoFourSeason - with its M+S marking - may be more appropriate for motorhome use than Vanco, there's no particular reason to believe it will be superior to Michelin's "Agilis Camping", as the latter is also M+S marked. Link to comment Share on other sites More sharing options...
goldi Posted October 11, 2012 Share Posted October 11, 2012 Morning all, I always thought that the reason to fit camper tyres was because of the height and thus, sway at roundabouts etc on coachbuilts and a. class that stiffer walls was required. I intend fitting toyo ho9 to my van which a pvc adria twin x250. I do share Trackers concern for the hard ride that you get these days, it is such ajoy to get on French tarmac. I believe road surface technology has alot of catching up to do in UK Link to comment Share on other sites More sharing options...
Tracker Posted October 11, 2012 Author Share Posted October 11, 2012 It has been decided between myself and the dealer that five new Michelin Agilis Camper 225/70R15 LI 112 will be supplied and fitted by themselves together with new valves and balancing. However it seems that their suppliers are awaiting a new batch of tyres from Michelin which will not be here for about 3 - 4 weeks - but at least they will all be identical and factory fresh and I can wait a month. So with air suspension fitted which definitely helps the ride I will be all set to replate to 3850 kg with the aid of SVTech (£288). Now I turn to wonder how many hurdles VOSA or the DVLA will find to place in my path for me to jump over!!?? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 11, 2012 Share Posted October 11, 2012 goldi - 2012-10-11 10:50 AM ...I always thought that the reason to fit camper tyres was because of the height and thus, sway at roundabouts etc on coachbuilts and a. class that stiffer walls was required... The claimed advantages of 'camping-car' tyres for motorhomes and the construction features are highlighted on the Continental website http://tinyurl.com/8s7fzw9 It's unlikely that a motorhome (whatever its design), fitted with similar specification (size and load-index) 'camping-car' or 'white van' tyres inflated to the same appropriate-to-load pressures, will noticeably sway less when cornering with the former tyre type than with the latter. The amount of 'sway' will mostly depend on the particular motorhome's spring stiffness and the height above the ground of its centre of gravity. Although tyres will be a factor in the 'sway' equation, if it reaches the point during cornering where the stiffness of the tyres' sidewall begins to play a significant role, the vehicle will probably be out of control. (You are aware that the Toyo H09 is a 'full-house' winter tyre? http://www.toyo.co.uk/tire/pattern/h09 Link to comment Share on other sites More sharing options...
goldi Posted October 11, 2012 Share Posted October 11, 2012 Hello again, The last picture which states for stronger transverse support is the point I was trying to get across. There are many motorhomers who have rear air suspension fitted to reduce roll at roundabouts. My pvc is fitted with Bridgestone duravis which have done 42000 miles with approx 4mm left on the front drive axle and 7mm on the rear. The tyres were fitted by Fiat when new and are standard fitment to Fiat vans. norm Link to comment Share on other sites More sharing options...
Brian Kirby Posted October 11, 2012 Share Posted October 11, 2012 goldi - 2012-10-11 2:34 PM Hello again, The last picture which states for stronger transverse support is the point I was trying to get across. There are many motorhomers who have rear air suspension fitted to reduce roll at roundabouts.......................... norm Yes Norm, but I think these are two different things. The transverse support referred to on Conti's website is, I'm pretty sure, reference to the tyre alone, meaning it has a stiffer sidewall to resist sidewall "squish" when laterally loaded, for example when cornering. This will not provide significant stiffening across the axle, though it may beneficially reduce some of the "wallow" that some vans suffer. What I think you are after is anti-roll provision, to prevent body roll on bends, roundabouts etc. Providing you fit the kind of air assistance that does not interlink the two inflatable units, this will be achieved. Our van has the simplest, and cheapest, version, with each sac individually inflated via it's own inflation valve. The air volumes involved are quite small, and the pressures generally quite low, so a bicycle pump is all that is required to adjust the pressures. Link to comment Share on other sites More sharing options...
Tracker Posted October 11, 2012 Author Share Posted October 11, 2012 Experience suggests that the best way to reduce body sway and roll is to corner with less gusto as three and a half tonnes of motorhome can hardly be expected to handle like a family hatchback! Each to their own, but I would never buy air suspension to improve handling or reduce body sway as in 40 odd years of motorhoming I have never found these aspects to an issue. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 11, 2012 Share Posted October 11, 2012 Stiffening the springing of a motorhome's rear suspension, whether by uprating the original metal springs or adding spring assistance of one kind or another (or even inflating the tyres to their maximum design pressure), should reduce body-roll but at the risk of ride quality suffering. Adding an anti-roll bar has no continuous effect on ride quality as the bar's action only occurs when the vehicle begins to roll during cornering. An anti-roll bar can be retrofitted to X250 Ducatos though, according to this Fiat webpage, the Ducato camping-car chassis already have them: http://www.fiatcamper.com/extras/en/faq Link to comment Share on other sites More sharing options...
Tracker Posted October 11, 2012 Author Share Posted October 11, 2012 Derek Uzzell - 2012-10-11 6:03 PM An anti-roll bar can be retrofitted to X250 Ducatos though, according to this Fiat webpage, the Ducato camping-car chassis already have them: Having spent some time with my arms entwined around the rear anti roll bar whilst I fitted the air suspension I can safely say the my van on the Fiat Camper ( the one with the wider rear wheelbase than front) does indeed have a rear anti roll bar fitted! Link to comment Share on other sites More sharing options...
George Collings Posted October 11, 2012 Share Posted October 11, 2012 Derek. An anti-roll bar in addition to combating roll also stiffens the ride when only one wheel goes over a bump. In roll the stiffness is twice as great as in bump. It is only when a traffic calming type bump is negotiated deflecting both wheels on an axle identically that the roll bar has no effect. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 12, 2012 Share Posted October 12, 2012 George Collings - 2012-10-11 7:33 PM Derek. An anti-roll bar in addition to combating roll also stiffens the ride when only one wheel goes over a bump. In roll the stiffness is twice as great as in bump. It is only when a traffic calming type bump is negotiated deflecting both wheels on an axle identically that the roll bar has no effect. Sure, that's why I wrote "...no CONTINUOUS effect on ride quality..." In Herefordshire, where I live, all the roads are billiard-table smooth, so an anti-roll bar has an effect only when cornering. ;-) Nevertheless, if the objective is to counteract excessive body-roll and minimise the likelihood of screwing up a vehicle's ride quality, adding an anti-roll bar should be preferable to fitting stiffer springs, adding spring assisters, inflating tyres to maximum pressure, or swapping tyres for ones with stiffer sidewalls. Link to comment Share on other sites More sharing options...
goldi Posted October 12, 2012 Share Posted October 12, 2012 Morning all, Thank you for the information on the anti roll bar from fiat Mr Uzzell , I did,nt know they didsupplied them as an after market product. norm Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 12, 2012 Share Posted October 12, 2012 goldi - 2012-10-12 9:31 AM Morning all, Thank you for the information on the anti roll bar from fiat Mr Uzzell , I did,nt know they didsupplied them as an after market product. norm An anti-roll bar is factory-fitted to motorhomes built on an X250 'camping-car' chassis and, presumably, this bar could be retro-fitted to X250 motorhomes built on a non-camping-car 'ladder' chassis-cab base. But I'm not sure if that bar could be fitted to a motorhome based on an X250 panel van. JSA is a French company http://www.jsa.fr/ specialising in suspension-related components that include anti-roll bars that can be retro-fitted. One of these is advertised as being suitable for an X250 chassis http://www.jsa.fr/uploads/anti-roulis-kit-bleu-arriere-x250-phase-iii-037110-n00497-01.pdf but, once again, I don't know if this would go on a panel van. (The drawings suggest not.) Link to comment Share on other sites More sharing options...
Robinhood Posted October 12, 2012 Share Posted October 12, 2012 Goldschmitt in Germany also do an anti-roll bar for the rear of the X250. From the catalog it isn't clear whether this version fits the panel van, BUT, the information for the item for the previous x244 model is clear that that particular item doesn't. That then begs the question as to whether the omission of similar information for the X250 version implies that it does (or doesn't :-S ). Link to comment Share on other sites More sharing options...
Brian Kirby Posted October 12, 2012 Share Posted October 12, 2012 Derek Uzzell - 2012-10-11 6:03 PM Stiffening the springing of a motorhome's rear suspension, whether by uprating the original metal springs or adding spring assistance of one kind or another (or even inflating the tyres to their maximum design pressure), should reduce body-roll but at the risk of ride quality suffering. I have to say this has not quite been my experience. The Driverite units were originally fitted to reduce a tendency for the van to ground its tail. By raising the ride height at the rear, this was successful. The Driverite units replace the plastics composite spring assisters fitted by Ford (Transit base), but appear to behave differently. On short axle movements they appear more compliant, somewhat reducing rear suspension harshness. Not by a huge margin, but a definite improvement over minor irregularities. The air bags are of quite small volume, however, so longer axle movements meet increasing stiffness as the work of compressing the air gets harder. This works well, and also works to reduce body roll since the effect is broadly similar. So,in our case, the tail stays out of trouble, the ride over minor irregularities is marginally better (and over the bigger ones that I can't dodge, subjectively no worse) and body roll is better controlled. Horses for courses, of course, but overall very satisfactory on all counts with our 'van. Link to comment Share on other sites More sharing options...
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