Steve928 Posted April 1, 2015 Share Posted April 1, 2015 A week or so ago I found this faulty or damaged area of tread on my NSF Agilis Camping (less than 1000 miles old). I took it to a Michelin dealer who helpfully suggested that I'd been driving with the wheel locked, which would be difficult with a front wheel and anyway the area is much shorter than the contact patch with the road. Michelin themselves were more helpful and sent me a form and instructions on how to return the tyre for inspection. I was convinced that it was a moulding fault, particularly if you look at the areas of missing rubber on the tyre's shoulder in the right of the picture. So today I went out to the garage to put the wheel in the boot, found the damaged area and then realised I was holding not the NSF wheel but the OSF wheel..? So it transpires that both front wheels have the same or similar fault, or damage as it now seems it must be. So, any ideas how this could have been caused, because frankly I'm stumped? What about on the transporter either to or from the MH manufacturer - anyone know how they are loaded and on what surface they sit? I realise that I'll have no chance of holding anyone responsible for this and will have to take it on the chin, but I would like to get an idea of what could have caused it anyway. P.S. the 'feathering' that you see is on the leading edge of the tread blocks. Link to comment Share on other sites More sharing options...
Keithl Posted April 1, 2015 Share Posted April 1, 2015 Steve, When a vehicle is loaded on a transporter it is quite normal practice to drive it up to a 'Bar' located on the deck of the transporter and then secure it with ratchet straps. Something like the picture below... It looks very much to me like this 'Bar' has fretted the tread of the tyre. Have you approached the selling dealer to comment on the damage to your tyres? If not this would be my next port of call. Keith. Link to comment Share on other sites More sharing options...
Steve928 Posted April 1, 2015 Author Share Posted April 1, 2015 Thanks Keith, that is exactly what I was beginning to suspect and your picture is really useful. It does indeed appear to be consistent with damage caused by a narrow bar of some sort. As you say, looks like the dealer will be my next port of call (wish me luck..!). Link to comment Share on other sites More sharing options...
StuartO Posted April 1, 2015 Share Posted April 1, 2015 On the face of it damage to a short section of the circumference of a tyre like this, on both front tyres, has to be due to fairly violent contact with some feature of the road surface or something lying on it. It's difficult to imagine how it could happen without the driver being aware so if you can't remeber any incident, has anyone else driven your MH who might? Maybe an experienced tyre fitter could speculate, based on tyre damage he's seem on other vehicles. If Michelin have been helpful why not let them see the tyres - except of course that will mean you taking them off and needing to fit two replacement tyres while they are away. Link to comment Share on other sites More sharing options...
Steve928 Posted April 1, 2015 Author Share Posted April 1, 2015 P.S. Do you have a link to a larger version of your chock picture please? Link to comment Share on other sites More sharing options...
Steve928 Posted April 1, 2015 Author Share Posted April 1, 2015 Other than delivery mileage (8 miles IIRC) and any other mileage done by the dealer then no, Stuart, nobody else has driven it. I really can't see it being on-road damge due to the limited area that is affected and the fact that the rubber has featherred forwards in relation to the road surface. Yes I suppose I could send both tyres to Michelin to get their opinion but you've already mentioned the problem in doing that. Then there's the fact that you effectively have to sign away ownership of the tyre as Michelin warn that the testing process may itself damage the tyre and you ay not get it back. Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted April 1, 2015 Share Posted April 1, 2015 Chaffing against or being lashed against a chock support(possibly even a rough timber skid?)would be my thoughts also.... :-S Link to comment Share on other sites More sharing options...
Steve928 Posted April 1, 2015 Author Share Posted April 1, 2015 For the sake of completeness here are both front tyres together. Link to comment Share on other sites More sharing options...
Muswell Posted April 1, 2015 Share Posted April 1, 2015 A serious question. Do you think it matters since it is such a small area? Link to comment Share on other sites More sharing options...
Keithl Posted April 1, 2015 Share Posted April 1, 2015 Steve928 - 2015-04-01 2:11 PM P.S. Do you have a link to a larger version of your chock picture please? Sorry Steve but no, it took quite a while on Google to find that one. Muswell - 2015-04-01 3:02 PM A serious question. Do you think it matters since it is such a small area? And yes my personal thoughts would be that it did matter. You do not know what damage has been caused to the carcase of the tyre below that surface damage. And this is just my opinion from experience working with prototype cars and tyres over the last 25 or so years. Keith. Link to comment Share on other sites More sharing options...
Steve928 Posted April 1, 2015 Author Share Posted April 1, 2015 I'll ask the supplying dealer to replace both tyres and let you know how I get on. I have other wheels to use in the interim so they can return the tyres to Michelin for their opinion if they so wish. The cab/chassis/motorhome will have had many transporter journeys in between Sevel, AL-KO, Bailey and the dealer in it's short life so who knows where the damage occurred. Having seen the angle at which the push-me-pull-you cab pairs arrive on the transporter though I bet mine was on the bottom of the front pair with almost the weight of two cabs bearing down on the wheel chock. Others must suffer the same damage I guess. Link to comment Share on other sites More sharing options...
Brian Kirby Posted April 1, 2015 Share Posted April 1, 2015 Have you tried measuring the tread depth directly in the area in question, and again immediately on either side of that area? It looks like a tyre that has spun, or locked under braking. I accept that the area in question is smaller than the tyre footprint, so unlikely to be due to a skid, but the way the compound has feathered suggests something like that happened. As it appears, either the tyre was rotating and the van static, or the van moving with the tyre, perhaps only momentarily, not rotating. I should have thought that Keiths "bar" would have been more likely to feather the tyre laterally, not circumferentially. Measuring the tread depth should reveal whether, as seems likely, material has been removed from this area. Possibly a momentary slip, or lock, going over something that gave only a small contact area? Could the delivery driver have tried to drive off over that bar? Even so, how many miles have you driven since delivery? I'd have thought the feathering would have worn away within a few hundred miles of it happening. I'd think it must be quite recent. Link to comment Share on other sites More sharing options...
Keithl Posted April 1, 2015 Share Posted April 1, 2015 Steve, If you go to the dealers try looking at new vehicles in stock and see if any have suffered the same damage, it could help your case! Keith. PS And not all 'Bars' as I have described are plain round bars or tubes, some are folded from perforated steel sheet which is really quite aggressive. Link to comment Share on other sites More sharing options...
Will86 Posted April 1, 2015 Share Posted April 1, 2015 My guess its from the wheel scuffing against whatever it was locked against. I doubt there has ever been any film of how wheels and tyres react when clamped. While the vehicle itself may jump up and down and back and forth, the wheels set on springs will oscillate to suit themselves and the tyres likewise producing a myriad of movements. Will Link to comment Share on other sites More sharing options...
StuartO Posted April 1, 2015 Share Posted April 1, 2015 My car transporter trailer has tubular wheel chock bars similiar to these in the photo and I have had no experience of tyre damage on the car. I find it difficult to see that being strapped against a wheel chock of that type could cause this tye of damage to a tyre no matter how tightly (or slackly) it was strapped down. Motor movers on caravans force a very abraisive drive bar against a tyre and I can't see those doing that sort of harm either. It would surely have to have been a much rougher/sharper contact surface to do that sort of damage - like the ground level spiky devices which are used to prevent access to vehicles. Even a metal kerb edge wouldn't damage a tyre like that. Link to comment Share on other sites More sharing options...
Steve928 Posted April 1, 2015 Author Share Posted April 1, 2015 To respond to some of the points raised, not necessarily in order. I can't see how this would have been caused by any kind of skid with the wheel locked. That would surely produce an oval area of damage, heaviest at its centre and not the kind of even band across the full width of the tyre that we see. Furthermore I think that I mentioned somewhere above that when the damaged area is in contact with the ground, the feathering (as we are calling it) is to the front i.e. the van would need to have been travelling backwards to displace rubber in this direction. About the only (comical) scenario that I could come up with would be the van being dragged backwards repeatedly with its front wheels locked over a very abrasive cattle-grid! Equally I can't see how any damage due to a spinning or skidding wheel would look like this. Then of course I'm pretty confident that no wheel locking, spinning or skidding has taken place. The tread depth is marginally less across the damaged area indicating perhaps that some rubber has been displaced to create that feathering effect. The tyres have done about 600 miles. Personally I think Keith's theory is bang on the money. Imagine this cab being the lower of a pair joined back to back and weighing c. 2 tons loaded at about 45 degrees on the transporter, with the front tyres bearing against a 50mm metal tube and shimmying about while on the road. Could there be enough friction generated to deform the tread? But then, as Brian points out, why is there no lateral feathering of the tread also? Or perhaps that has worn off in those 600 miles.. I'll take up Keith's idea of a look around the showroom for similar damage. There are enough vans there to mean that if this is the cause then there may be others present (although not all will have been back to back cab units - I don't think that complete chassis are carried at such extreme angles.) As to 'does it matter', then perhaps not, but if the tyre has been subjected to enough pressure and heat to effectively melt the tread then I'm not qualified to say what effect that might have had on the carcass. One thing's for sure, it's going to be hard to resolve because (as noted often on here) dealers are very, very unwilling to approve anything that might eat into their own margin and nobody can prove at which point in the vehicle's life, right from it leaving Sevel to now, it happened.. Link to comment Share on other sites More sharing options...
teflon2 Posted April 1, 2015 Share Posted April 1, 2015 Just a thought but have you been on a RORO ferry in the motorhome if so and you've been held at the point where the ramp meets the loading road it could cause similar damage. John Link to comment Share on other sites More sharing options...
rolandrat Posted April 1, 2015 Share Posted April 1, 2015 It seems to me that the motorhome has been subject to a rolling road brake test where the front wheels were locked on and the roller power trying to carry on. What are the rear tyres like? Wouldn't it be a good idea to swop them round? Link to comment Share on other sites More sharing options...
Guest peter Posted April 1, 2015 Share Posted April 1, 2015 Looks to me like someone in the factory was a little too heavy on the brake test rollers. The abrasive roller was left to rotate after the wheel had stopped rotating. Ergo abrasive roller removed rubber from tyre. That's my logical theory and sounds highly plausible. Ha ha Roland rat beat me to it as I was typing. Must be a psychic phenomenon. :D Link to comment Share on other sites More sharing options...
Steve928 Posted April 1, 2015 Author Share Posted April 1, 2015 No, no ferries John. Hmmm, brake test rollers - I hadn't thought of that and it does indeed seem like a plausible explanation. Good thinking. It seems so obvious now that you both have suggested it. Link to comment Share on other sites More sharing options...
Guest peter Posted April 1, 2015 Share Posted April 1, 2015 Warranty job then. Especially with virtually no mileage on them. :D Link to comment Share on other sites More sharing options...
George Collings Posted April 2, 2015 Share Posted April 2, 2015 I have been a round a couple of car factories over the years and it may have been there or perhaps on a documentary film but at the end of the line the vehicle was driven quickly over a set of tubular bars . The device looked like a cattle grid assembled by a drunk as the approx 2" diameter tubes were both angled anything up to 15 to 20 degrees off the horizontal but also at perhaps 3" up and down where they crossed at roughly the width of the vehicles track. The object was to work vigorously shake the suspension bushes prior to checking steering alignment. Its pure conjecture that perhaps an incident occurred on something like that boneshaker. If so its a change from the pre x250 Sevel line where buried in the owners handbook were instructions that track should be checked by a dealer after 150 miles. Failure to do so resulted in scuffed out tires by about 3K . It happened to a friend on his maiden trip half way up Norway en route to North Cape. Why would a brand new vehicle be on brake rollers. Link to comment Share on other sites More sharing options...
George Collings Posted April 2, 2015 Share Posted April 2, 2015 I have been a round a couple of car factories over the years and it may have been there or perhaps on a documentary film but at the end of the line the vehicle was driven quickly over a set of tubular bars . The device looked like a cattle grid assembled by a drunk as the approx 2" diameter tubes were both angled anything up to 15 to 20 degrees off the horizontal but also at perhaps 3" up and down where they crossed at roughly the width of the vehicles track. The object was to vigorously shake the suspension bushes prior to checking steering alignment. Its pure conjecture that perhaps an incident occurred on something like that boneshaker. If so its a change from the pre x250 Sevel line where buried in the owners handbook were instructions that track should be checked by a dealer after 150 miles. Failure to do so resulted in scuffed out tires by about 3K . It happened to a friend on his maiden trip half way up Norway en route to North Cape. Why would a brand new vehicle be on brake rollers. Link to comment Share on other sites More sharing options...
Steve928 Posted April 3, 2015 Author Share Posted April 3, 2015 George Collings - 2015-04-02 11:07 PM Why would a brand new vehicle be on brake rollers. AL-KO build the unit for the motorhome converter using a cab and front axle from Spain and a chassis and rear axle from Germany, so presumably they do a roller test to check out the completed chassis' systems. Link to comment Share on other sites More sharing options...
George Collings Posted April 3, 2015 Share Posted April 3, 2015 I had it in my head that converters bought in the cab units and chassis and assembled them to Al-Ko spec but not sure where I saw it. It could well be the case for some converters while others buy the cab + chassis from Al-Ko. Its strange damage. I remember something about slight transverse carcase thickness variation being due to the way the rubber / fabric layers are laid into the mould. It arrives as a strip and the ends are overlapped during the layup process. The vulcanization process smooths most of it out but I have seen some slight bulging on LCV tyres. Could it be that by coincidence some force among those already mentioned picked up the ends of the strip that perhaps were less than perfectly joined Link to comment Share on other sites More sharing options...
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