weldted Posted February 23, 2018 Share Posted February 23, 2018 Hi, I have a 2012 Elddis Aspire 255 on the Boxer 130. I have uprated the van to 3850 kgs MAM the gross train weight remains the same at 6000 kg. this is the first trip with the uprate. The van has been fitted with rear semi air and 225/70/15 tyres. So far on this trip we have covered just over 5,000 miles. I have noticed in the last couple of thousand the van has a tendency when cornering at a reasonable speed it feels as it a rear tyre was soft as the van back of the van feels like it's going to swing around. It is the same right or left. Have re checked the tyre pressures 5.5 bar as per Michelin spec. Have tried thr air suspension at .5 bar 1 bar 1.5 bar etc up to 3 bar. No difference to handling. Removed all water etc, nine weeks into trip so not a lot of payload. Moved payload around to try different loading no effect. Have had this van from new never had this before. Did wonder about shock absorbers but the van still over steers on a long bend by which time the absorber would have been fully compressed. It's not a gentle swing if not controlled will drift really bad. Ideas please. Link to comment Share on other sites More sharing options...
Keithl Posted February 23, 2018 Share Posted February 23, 2018 Ted, A question while I'm getting my head around your situation, have you just replaced the rear tyres or have you replaced all four? Keith. Link to comment Share on other sites More sharing options...
weldted Posted February 23, 2018 Author Share Posted February 23, 2018 Hi, thank you for your reply, only the rear tyres were replaced 225 against 215. Have gone to the extreme of stopping front and rear over to see if that made any difference. The problem was not really noticeable at the start of the trip. The front 215,s had good tread when we left Plymouth but have worn down very quickly evenly across the tread. I normaly reckone on getting more mileage out of then. The van has done 31,000 at the mot before we left I had the tracking checked. So to say I am puzzled is an understatement. Link to comment Share on other sites More sharing options...
Tracker Posted February 23, 2018 Share Posted February 23, 2018 When we uprated an Autotrail Cheyenne to 3850kg several years ago we were advised to replace all four tyres with uprated 225 section tyres to help with stability and make it easier to carry a spare that matched all four tyres, which we did and in conjunction with Dunlop air assistance on the rear that was all we did. I too experimented with tyre pressures and air suspension - well inflatable bumpstops in reality - and altering the suspension pressure up or down fron the recommended pressure made no discernable difference to ride or handling whereas altering tyre pressures made a huge difference. We found the Autotrail and Fiat recommended tyre pressures far too hard all round and eventually settled on much lower tyre pressures to improve the ride but with the rears always 5 - 8 psi higher than the fronts to avoid wallowing and understeer, and we had no problems with handling at all. I am not suggesting anyone else reduces their tyre pressures as it can have all manner of legal implications. Are you able to discern a more noticeable body lean on bends or does it just feel wrong? I have heard in the past of the bolts that secure the body to the chassis becoming loose over time but I am a bit clutching at straws there. Although you have tried switching wheels I kinda suspect that different tyres front to back might have something to do with it, but that your van was OK when you left home does suggest that maybe something else is having an influence? Not only are the tyres different sizes but the sidewalls may be different with the 225s stiffer than the 215s? Being an experienced motorhomer competent with the mucky bits, I expect you have checked the security of the rear, and front, springs, dampers, steering, roll bar, flexible joints etc? Don't mean to insult your intelligence there, more grasping at anything? Link to comment Share on other sites More sharing options...
747 Posted February 23, 2018 Share Posted February 23, 2018 I used to have a 2006 Elddis Autoquest and found that too much pressure in the front tyres gave an impression of oversteer. Another point to consider might be that the rear suspension is now too rigid. This could cause the whole vehicle to lean on bends (where you are having the problem) and give a feeling of oversteer. Try it without any pressure in the system. Link to comment Share on other sites More sharing options...
Keithl Posted February 23, 2018 Share Posted February 23, 2018 weldted - 2018-02-23 11:58 AM Hi, thank you for your reply, only the rear tyres were replaced 225 against 215. Have gone to the extreme of swapping front and rear over to see if that made any difference. The problem was not really noticeable at the start of the trip. The front 215,s had good tread when we left Plymouth but have worn down very quickly evenly across the tread. I normally reckon on getting more mileage out of then. The van has done 31,000 at the mot before we left I had the tracking checked. So to say I am puzzled is an understatement. Thanks Ted, Your comment on wearing faster than usual also goes along with my theory, bear with me... I am assuming your MH has ABS/ASR/traction Control whatever? So when you are cornering the front wheels are turning faster than the rears as they have the smaller diameter tyres, the ABS/ASR senses this as they are slipping or spinning and so applies the brakes on the fronts ONLY! You probably aren't even aware of this happening! What then happens is as the fronts are braked they tend to 'tuck in' slightly and hence make the rear feel like it is sliding out of control. I think you need to get new tyres fitted to the fronts to match the rear and then see what happens. And go back to whoever told you to only replace the rears and see what they have to say? This is my thinking on the matter so open to further suggestions, but Please let us know how you get on. Keith. Link to comment Share on other sites More sharing options...
weldted Posted February 23, 2018 Author Share Posted February 23, 2018 That was one of the reasons I swapped the wheels around but it had no effect. The 215s will be changed for 225s on my return to the Uk as they were only 1.5 mill worn I thought I would get one more trip out of them. But it was fine foe 3000 miles now it is scary how it reacts. Having to return to Limoges in one hit other than a short sleep when an artic went by it pulled the van all over the place. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 23, 2018 Share Posted February 23, 2018 Even if Ted’s 2012 Boxer had an ESP system (which I doubt it has) this should only intervene in an extreme situation when a significant loss of tyre grip is detected. The fact that the circumference of the motorhome’s front tyres is slightly smaller than that of its rear tyres should not cause the noticeable ‘oversteering’ that Ted is complaning about. An Aspire 255 has a considerable rear overhang (photo attached) and, if a lot of weight were right at the back, this would certainly not help the vehicle’s behaviour when cornering. In principle (and assuming there’s no excessive rear loading) if the motorhome’s front tyre-pressures are lower than the rear tyres’ and the original rear spring rates have been augmented by fitting air-bellows, the vehicle should tend more towards understeer than oversteer. I can’t see worn dampers being the culprit if (as Ted says) the motorhome oversteers on a long bend. Lift-off oversteer could probably be provoked by deliberately driving hard through a bend and suddenly lifting off the throttle midway round, but I’m sure that’s not what Ted’s doing. The Elddis did not exhibit this behaviour prior to its weight being uprated. Ted has said that, for the first half of his trip things seemed OK and experimenting with the air-bellows’ inflation-pressure and swapping tyres front-to-rear have made no difference. The vehicle also displays the same symptoms on left or right bends. As Tracker mentions, a very careful check needs to be made of the suspension components as Ted’s observation "It's not a gentle swing if not controlled will drift really bad” suggests that there is something mechanically wrong. If my motorhome had a handling problem like this and I could not pin down the cause, and I believed the behaviour was potentially dangerous, I’d ask a motorhome dealer’s technician to drive it and offer a diagnosis. Link to comment Share on other sites More sharing options...
Brian Kirby Posted February 23, 2018 Share Posted February 23, 2018 I'm assuming Ted is now on the return leg of his trip, and that he was not towing his laden trailer when he began to notice the oversteer. If the van behaved alright outward, with laden trailer attached, and was still OK on the remainder of the trip minus the trailer, I think Derek's advice to get the rear end checked is timely. In fact, my suggestion would be to get it looked at a.s.a.p. since what he describes seems to suggest a radical fault that has developed since the rear uprating plus towbar fitting were carried out. Neither should, as far as I know, have involved loosening the rear beam axle clamps or spring attachment points/shackles, but it sounds as though the rear axle is "floating" for some reason. I guess heavily worn bushes at the mounting points, perhaps especially on the shackle, would allow the axle to slop enough to be detectable in driving. The extreme would be if a spring had snapped, but I can't imagine Ted would have failed to notice the impact on the van had that happened. I think a trip to a Fiat dealer at the earliest opportunity would be wise, at least for the peace of mind in knowing that everything mechanical is in good order. Ted says Limoges. There is Groupe Rouyer (Fiat Professional) ZI NORD - 19 AVENUE DES CAMBUSES, 87280 LIMOGES Tel: 0033 5 81 94 36 29, GPS N45.89017 E1.27403, if this helps. It is about 4 miles due north of the centre of Limoges, just off (south side) the N520. Signed: Limoges nord, ZI nord, just south of a big commercial zone. Easy looking access. Suggest checking before visiting, as the address is from the French camper Assistance website, which lists a different Fiat Pro agent at the same address, but Rouyer's own website ( http://tinyurl.com/y7p68tcx ) gives the above as their address. Link to comment Share on other sites More sharing options...
weldted Posted February 23, 2018 Author Share Posted February 23, 2018 Many thanks Brian. I've had the Towbar fitted since 2013 and have towed the trailer many times mostly at or near its max. This is the first trip with the semi air kit and 225 tyres. Towed the trailer with van right at its max loading to our cottage near Limoges, max 50 mph. Left trailer at cottage left for Portugal with van around 3800 kgs. Fine all the way down max speed 55. Been away 9 weeks last couple of weeks noticed this problem until then fine. It feels when cornering as if the back of the van is going to slide outwards as if you had a soft tyre. Our dog suffered a severe stroke whilst away, a quick call to a Portugese vet then ran for the cottage. Our vet lives opposite us and is brilliant so 850 miles in 20 hrs happily after an mri scan no brain damage. But the drive back was a nightmare. Going to jack it up in the morning to see if anything is adrift. Link to comment Share on other sites More sharing options...
Tracker Posted February 23, 2018 Share Posted February 23, 2018 weldted - 2018-02-23 8:16 PM Going to jack it up in the morning to see if anything is adrift. Hope the dog is OK as I do know how stressful that can be at home let alone in a different country. I expect you already know that when jacked up, depending where you jack, the suspension is often under even more load and anything amiss is less likely to show up. If you have access to a ramp it might give you a better clue but a decent MOT type garage with a four wheel drive on ramp and a crowbar to lever check loaded joints and bushes might be better, if available, especially if they will let you look with them and point things out? Link to comment Share on other sites More sharing options...
weldted Posted March 1, 2018 Author Share Posted March 1, 2018 Hi Tracker re the steering, van has been examined by Peugeot and an control tech no obvious faults discovered. I have also gone through everything myself, when I fitted the semi air, everything was torqued down van driven for about ten miles torqued again. Just check torque again all correct no sign of any movement have taken everything loose out of van, weighed it 3560 kg still same problem? Have ordered two 225/70 R15 agilis camper car tyres so all four will be the same, but I don't think that is the answer. Not spending too much time on it at the moment dog has taken priority, he seems to be recovering well but still unsteady and head to one side. Still recovering from the 850 mile dash back to Limoges from Lisbon, arrived late last Thursday saw our vet who is brilliant he phoned up late that night and arranged for Roly to have an MRI scan the next morning. Fortunately there is no sign of brain damage just what appears to have been a very small bleed. Thank you for your thoughts. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 2, 2018 Share Posted March 2, 2018 weldted - 2018-03-01 10:59 PM ...Have ordered two 225/70 R15 agilis camper car tyres so all four will be the same, but I don't think that is the answer... You might want to contact SVTech http://www.svtech.co.uk/contact/ about this ‘oversteering’ problem as it seems to be standard practice for them to advise fitting air-bellows to a motohomes rear axle and replacing original 215/70 R15 tyres with 225/70 R15 tyres when uprating the vehicle’s maximum overall weight from 3500kg to 3850kg. If other motorcaravanners have experienced oversteering after weight-uprating SVTech will probably be aware of this. I can’t see why fitting an air-bellows system and upping the rear tyre-size slightly should result in the change in behaviour you are experiencing. I’m guessing that most people advised by SVTech to go from rear 215/70 tyres to the 225/70 size bother to do the same with the front tyres. And, while having all four tyres matching size-wise makes sense, I would have thought that if a motothome oversteers with 215/70 tyres on the front wheels and 225/70 tyres on the rear wheels, it’s going to oversteer more if 225/70 tyres are then fitted to the front wheels. The other thing is that (from what you’ve said) you only began to notice this odd behaviour some 3000 miles after the uprating had been carried out. I note that the motorhome has been inspected by Peugeot and Contrôle Technique people, but was the oversteering behaviour actually demonstrated to them? It’s one thing to go around the vehicle with a torque-wrench and for there to be no obvious faults found during an inspection, but if someone (Peugeot or CT guy) drives the motorhome (or is driven in the motorhome) and the vehicle clearly shows a nasty tendency to wag its tail, they should KNOW that something is wrong. Link to comment Share on other sites More sharing options...
weldted Posted March 2, 2018 Author Share Posted March 2, 2018 I took it hard round a bend fitter turned a bit white !! Link to comment Share on other sites More sharing options...
snowie Posted March 2, 2018 Share Posted March 2, 2018 Have you sought guidance on tyre pressures and front and rear balance? Now that you’ve had the chassis checked and you’ve got the tyre sizes sorted, the only other thing would seem to be the contact patch, Drive safe, Snowie Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 2, 2018 Share Posted March 2, 2018 weldted - 2018-03-02 10:54 AM I took it hard round a bend fitter turned a bit white !! But did the fitter think your motorhome was behaving ‘normally’ when you did this? Link to comment Share on other sites More sharing options...
monique.hubrechtsgm Posted March 2, 2018 Share Posted March 2, 2018 Looks to me a high point of gravity. The convertor is obliged to make this test on the proto type. Air suspension can have a influence on behavior but mostly on the positive site to under and oversteer. That is their core work. Having a sper diff on the rear will correct this. Hope you will find the cause. Link to comment Share on other sites More sharing options...
Tracker Posted March 2, 2018 Share Posted March 2, 2018 I seem to recall that when we uprated our Autotrail Cheyenne it was already well down tight on the rear suspension rubber bumpstops and I had to jack the body up leaving the wheels on the ground to get enough clearance to get the solid bump stops out and the inflatable ones in. On lowering the jack the air bellows were already well compressed without any inflation and as Ted states higher or lower air pressure made no real difference to the ride or handling of his van or to ours either. Grasping at straws, I wonder if Ted's van's rear suspension is less compressed than mine was and possibly the lack of immediate firm bump stop contact has the effect of allowing much more free movement body sway which once started applies the pendulum effect to the whole van? My inclination would be to refit the original bump stops and see what the effect on handling is as whilst it might not be the answer long term it might give clues about what to investigate or try next? I seem to recall reading somewhere that as well as looking like traditional beam axle bump stops the OE rubber 'stops' were part of the suspension compression equation and as such need to be under some compression to be effective? We once had an Autocruise Starspirit which had a huge rear overhang and that too could be pretty wayward especially in a strong wind or when being passed by a large truck at speed. That too (not Al-ko) had rear suspension that was well compressed and although unnerving at times I never felt dangerous. Looking at the overhang on Ted's van there may be a link btween his problem and suspension compression but none of the above answers why it was OK to start with and suddenly got a lot worse. Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 2, 2018 Share Posted March 2, 2018 Ted, in view of your comment about the artic buffeting the van, I assume you hadn't experienced this before the chassis was uprated? I also believe this was the first trip you'd undertaken after the uprating? You clearly kept your speed down while running with the trailer, and seem to have done so after you parked the trailer. But, you say you left Limoges for Lisbon with the van at 3,800kg, so presumably heavier loaded that you had normally driven it before the uprate? If the tyre pressures are AOK, and the rear end has been thoroughly checked, I'm beginning to wonder if the extra load is what is causing the upset? The van is on the "light" chassis, originally plated at 3,500kg. Max front axle load 1,850kg, max rear 2,000kg, so plated up to 3,850kg it is well beyond the original limits of its design. I'm beginning to wonder if the van as now driven is just revealing that to be the case, despite the air assistance at the rear and the larger rear tyres? One other thing that does occur to me, is the nature of the air assistance. Are the bellows permanently cross linked, or are they inflated individually? If they are cross linked, is it possible to separate them, so that there is no pressure transfer from one side to the other? I'm wondering if air is being displaced from the outside bellows on bends to the inside bellows, as the former becomes compressed by roll forces, so accentuating roll, and if that is possibly upsetting the suspension geometry in some way. Greater roll would pull the front wheels further off vertical than normal, so might that induce roll-steer, which might transmit to the driver as oversteer? Edit to say just seen Rich's post above, which is along the same lines, but proposes a different remedy. Unexpected roll on bends can have an oddly quietening affect on passengers, says the one-time Citroen Dyane driver! :-D Might explain the pale-faced technician after Ted's well hard bend! The air assistance I installed on our Hobby was not linked left to right: each bellows had to be inflated individually. This stiffened the rear end resistance to roll, while leaving it agreeably compliant in other conditions. The bellows have little volume, so are easily inflated with a bicycle pump. As to selecting inflation pressure, my suggestion would be to park the van completely unladen on level ground, and measure the ground clearance at the rear bumper. Then re-visit the same location with the van fully laden and inflate the bellows (within their limits :-)) until the unladen rear ground clearance is reinstated. Note that pressure, and then experiment around that if necessary. Link to comment Share on other sites More sharing options...
Keithl Posted March 2, 2018 Share Posted March 2, 2018 Ted, You say you are now carrying 300 kg more payload than you have ever run at previously, where is this weight located? If it is behind the rear axle this could be a typical case of the 'Tail wagging the dog'!!! Try re positioning your load further forward and see if that makes any difference. Alternatively if the load is higher than the original CoG try lowering the weight. Keith. Link to comment Share on other sites More sharing options...
weldted Posted March 3, 2018 Author Share Posted March 3, 2018 Many thanks for all your comments, van has been uprated to a max of 2200 rear axle 1850 front axle. One of the requirements to achieve the rear axles 2200 rating was to fit 225/70/15 up from 215/70's Semi air each unit is independent so no cross transfer of air, no leaks. Van is now stripped of all contents that are not permanent fixtures, even removing the Tow-bar. Still have the roll. As said previously the first few weeks of the trip handled fine no problems, stable on motorways when overtaking or being overtaken by arctics. Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 3, 2018 Share Posted March 3, 2018 Ted, how are the bellows inflated (i.e. manually, or via an on board compressor), and are there pressure gauges for each side, or only a single gauge? You hadn't previously mentioned roll, only oversteer. Are/were you getting increased roll as well as the oversteer, or has the roll always been there? Edit to add, has anything been installed onto the roof (satellite dish, solar panels, aircon etc.)? Link to comment Share on other sites More sharing options...
Tracker Posted March 3, 2018 Share Posted March 3, 2018 The handling has obviously changed and it sounds as if the oversteer is being caused by body roll - unless the body roll is being caused by the chronic understeer? If it did not happen for the first 3000 miles logic suggests that the installation was good but that something has suddenly changed to alter the suspension or steering at around 3000 miles. I expect you have tried the air bellows at their maximum pressure just to see if that takes out any potential slack in that area caused by the change? Reinstalling the original solid suspension bump stops might help isolate whether it is air suspension related or not and whilst not dirctly curing the problem might lead you in the right direction? I appreciate that getting any sense from a snow disrupted UK might not be easy right now but maybe the air bellows supplier might be able to help? Similar uprating changes to tyres and suspension made no real difference to the ride and handling of our van except that at higher air pressure the ride was more harsh, but that van was always a handful in a gale even before the uprating and that did not really change although it did not dramatically oversteer without cause. Link to comment Share on other sites More sharing options...
Will86 Posted March 3, 2018 Share Posted March 3, 2018 Reading Welted's first post I believe he may be under the illusion that all M/H's should drive the same, whereas in reality they never do. Its all a matter of adjustment and learning their individual characteristics and driving accordingly. 10 different drivers would take 10 different views. Link to comment Share on other sites More sharing options...
Keithl Posted March 3, 2018 Share Posted March 3, 2018 Ted, I'm guessing your MH has Anti-Roll Bars so has a link broken? This would cause your problem and you seem to be saying the change happened rather quickly. Keith. Link to comment Share on other sites More sharing options...
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