New tyre blowout

[Borderer]

Thanks everyone.

 

I have had a look again at the tyre. Although the photo appears to show a straight line, the rubber appears broken/torn rather than have a sharp cut edge. The "straight" line appears to follow the line of the inner cord, one of which has separated from the rest yet is still attached at both ends, both at the tread side and the rim edge, as if the tyre has split along the line of the cord.

 

I am not excluding the vandalism theory, but as yet we have heard of nothing like that yet in the cul de sac where we live. The van has stood on my drive since return from the garage, so if such a thing had occurred it could only have happened prior to fitting (if that were to be the case then that could possibly have happened at any point in the supply chain) or on my drive. I will check my other tyres as carefully as I can.

 

I have taken lots of photos of the tyre before I return it to to the fitters tomorrow. I will see what they can tell from studying the damage.

 

Thanks again.

 

 

[Colin Leake]

Brian Kirby - 2014-01-26 12:52 PM

 

Borderer - 2014-01-26 10:56 AM

 

Just out of interest here is a picture of the damaged inside wall

On the evidence of that, I agree with George, take as many, detailed, close up, photos as possible. Also, check the manufacturing date mark on the tyre. It is just possible it was older than should have been fitted. It is clear the sidewall has blown out, but there seems to be quite a chunk of tread missing as well, which might indicate you ran over something on the road on that edge of the tyre. Is this at all possible?

 

Many years ago we had a similar tyre failure on a caravan on the first trip out after the tyres had been fitted. Turned out the date on the tyres showed they were much older than the tyres we had had removed. Company that fitted them were very good replacing the Dunlop's they had fitted with more expensive Avon's. They were very concerned that Dunlop had supplied new tyres that we already out of,date.

[spospe]

Now that I have seen a photograph of the damaged tyre, I can say that it reminds me of a blow-out that I had some years ago. The cause was a small rectangular piece of metal, about 4 inches by 3 inches which was flipped up by a front wheel and sliced through the sidewall of the rear tyre.

 

From what I can see in the photograph, this tyre blowout is a damage case, caused by road debris.

 

Edited to correct a spelling mistake.

[Will86]

Like the Concord that caught fire and crashed in France perhaps.

[Archiesgrandad]

I'm sorry but I suspect that the most likely explanation is that you've run over something. I've seen lots of punctures over a very long career, and that looks like damage from debris.

If you've ever tried to cut up an old tyre you will know how hard it is, and something has cut through the banding and the tread in one quick cut. You ain't gonna do that kneeling down by a van and reaching in and cutting with knife. I don't think it looks like damage from kerbing either as there is no damage to the rim.

AGD

[euroserv]

It looks like a manufacturing defect to me. I think the casing has separated suddenly and torn the cording apart.

The damage and debris that you can see would easily have been as a result of running while deflated. The casing could have even folded over itself while running flat, and that will tear the tread off quite easily.

 

The manufacturer will not own up to a manufacturing fault and the fitting firm will be unlikely to help beyond that.

Unfortunately you now have a good example of why not to waste money on expensive tyres.

[Derek Uzzell]

My experience is that a tyre manufacturer will admit to a manufacturing fault when the diagnosis is irrefutable.

 

Some years ago, having removed a wheel from one of my cars I discovered that the tyre's inner side-wall had cracked deeply right round the circumference close to the wheel-rim. The crack wasn't noticeable with the wheel in place and the car had passed its MOT test a few weeks before. As the reason I had removed the wheel was because I was giving the vehicle a check-over before selling it in the near future, I wasn't best pleased.

 

I bought a replacement tyre from the local tyre-fitting depot that had originally fitted the now-defective tyre and asked the proprietor to seek compensation from the tyre manufacturer (Semperit if I remember correctly). The defective tyre had done quite a few thousand miles and I eventually received £25 (about half the cost of the replacement).

 

It may be difficult in Borderer's case to be certain whether his tyre failed spontaneously or as a result of damage. Like spospe, I once had a car tyre 'blow out' explosively when it was penetrated by a small rectangular piece of metal. There was no doubt what happened in that instance as the metal rectangle cut straight through the tyre's tread and ended up inside the tyre.

 

The likely candidates for the blow-out are a manufacturing fault or damage caused when the motorhome was being driven, with the latter probably the prime suspect. I would have thought Borderer's tyre failure was caused by an external object rather than as a result of a manufacturing flaw.

 

Obviously there are other possibilities, such as the tyre having been accidentally weakened post-manufacture and before Borderer drove his motorhome after the tyre had been fitted to it. If the tyre had been deliberately harmed, the damage could have been caused within the tyre (where it's unlikely a carefully positioned cut would be noticed) and anywhere from Continental's factory in the Czech Republic until it arrived at the firm that fitted the tyre in the UK. I wouldn't rule out deliberate damage having caused the blow-out, but I'd have to put my paranoia hat on before seriously considering that option.

[Brian Kirby]

I've tried blowing the image up, but it is too pixellated to see any more detail. There is a lot of damage, and it seems beyond doubt that it was an explosive deflation. Other than that, between defect and striking some kind of bebris, even something launched by another tyre of another vehicle, I think it impossible to say just from pics - and I would think far from easy even with the tyre to examine. The clincher would be if there is something still inside the tyre, as Derek experienced. My impression is that the area that first failed is near the tread band, but either cause could as easily have caused that. The rest, as they say, is conjecture. Be interested to hear what Conti make of it, in due course. Very annoying for Borderer if they all decide it was debris, and a bit worrying for those of us with Continental tyres if they decide it was probably a defect! Lets hope he gets the benefit of the doubt - they are pricey tyres.

 

Our last van did not come with "Camping" tyres, though others of the same make and model did. Our present one did. The motorhome market is competetive, and the CP tyres, even, I would think if bought in bulk, are quite a bit more expensive than their white van, C designated, equivalents. If the van manufacturers and converters thought they need not bear that extra cost, presumably they would fit C tyres in lieu of CP? Something convinces them that the cost is desirable, and it can't be the demands of the buying public, as few seem to pay any attention to the tyres on a van until replacements are needed. The declared load carrying capability of the CP tyres is, in the cases I have investigated, no greater than that of the equivalent C tyre, with some slightly less. It is only the recommended pressure to carry that load which increases.

 

I was told a few years back, when Michelin XC Camping tyres were about the only CP tyre available, that they were basically 10 ply rated tyres sold and labelled as 8 ply rated, to give a greater factor of safety against overload. This was stated to have been due to a number of failures caused through overload on vans in France, and Michelin wishing to protect their (sacred in France) reputation. It made sense, but it was verbal so, although it came from a "man at Michelin", albeit a technical man, it may just have been company myth. Who knows?

 

Come to that, who knows the actual technical difference between an 8PR and a 10PR tyre? Ply ratings are strictly meaningless when applied to radial tyres, as the term refers to cross ply technology, so it is presumably a performance equivalence formula that must be applied by engineers. I can't imagine every size and type of tyre is submitted to ETRTO (or the US DOT!) for assessment, so presumably the manufacturers' engineers apply a code of practice in arriving at the applicable designation. Would be interesting to know if anyone is privy to the details of how it works, but it seems each manufacturer is free within reason to adopt different methods in constructing tyres to meet the required standard.

[Derek Uzzell]

Brian

 

Michelin's "XC Camping" tyre was not "CP"-marked (this began - in Michelin's case - with "Agilis Camping"), but it did specifically target the motorhome market and it did initiate the high inflation-pressure recommendations that continue today.

 

Michelin produces a Tyre Safety Guide that includes a section on CP-marked tyres. This is part of the relevant text:

 

"Motorhomes:

 

Motorhomes require tyres are that are adapted to their conditions of use. Apparenty, in 2003, the ETRTO (European Tyre and Rim Technical Organisation) changed the standard, as well as its recommendations relating to motorhome tyres, and now says "CP-type tyres have been designed to cater for the higher loads imposed by motor-caravans”, and that "it is strongly recommended that motorcaravans are only fitted with CP-tyres”.

 

At replacement, Michelin strongly recommends the fitting of CP tyres to vehicles originally homologated and fitted with CP tyres. The load on the tyre must not exceed its maximum limit for any reason, i.e. the load rating must be respected. The ETRTO also states that where CP tyres are used on the rear axle (single fitment), they must be inflated to a pressure of 5.5 bar instead of the normal pressure of 4.75 bar for example.

 

MICHELIN CP marked tyres are therefore specially designed to be driven at an inflation pressure of 5.5 bar (550 kPa). This higher pressure improves road holding and increases resistance to the challenging driving and usage conditions encountered by motorhomes, especially with regard to loads (occasional static and/or dynamic overload associated with this type of vehicle; considerable rear overhang, load imbalance, high centre of gravity due to highly positioned loads) and long-term periods of disuse."

 

It's evident that there's a view within the UK motorcaravanning community that 'camping-car' tyres (like Agilis Camping or Vanco-Camper) are a waste of money and one might as well buy cheaper "C"-marked 'white van' tyres. There's some justification in this view - after all (as discussed in another thread) why should one pay more for a "CP"-marked Vanco-Camper tyre when one could pay less for a "C"-marked Hankook RA18 equivalent that has a higher Load Index?

 

At the end of last week I e-mailed Continental, Michelin and the ETRTO and asked if they could provide me with details of the ETRTO standard that applies to "CP"-marked tyres.

 

Michelin has just told me that the 2013 ETRTO standards manual merely defines the "CP" suffix as an indicator of a commercial vehicle tyre for service on motor caravans. There are no special ETRTO technical 'rules' relating to "CP"-marked tyres: the suffix is just a marking that identifies a tyre as a motorhome-specific tyre designed to be capable of taking the higher loads often found on motorhomes. The "CP" marking enables a tyre to be identified as a motorhome tyre as opposed to a "C" marked van tyre or even a car tyre of the same size.

 

(I've yet to hear from Continental or the ETRTO, but I've no reason to doubt Michelin's information.)

 

What this apparently means is that there is no independent body overseeing "CP" tyre production and marketing and (rather like the "M+S" marking) it's up to the tyre manufacturer to decide whether a tyre qualifies for the "CP" suffix.

 

There may be a bit more to this, as Continental says that the ETRTO's standard relating to the "CP" suffix applies only to 8-ply-rated tyres. Nevertheless, it now seems that the "CP" suffix is purely an identifier, and does not prove that a tyre has defined technical attributes or that it has been tested differently from a tyre with a "C" suffix.

 

 

[George Collings]

The damage is too localised to have been caused by underinflation. The blowouts I have seen have usually involved underinflation that involves disintegration over over a wider area. In one in particular all the radial plies were intact but a great patch of sidewall rubber had let go and the sidewall looked like an anti fly screen.

 

It would have been a particularly devious offendor that bothered to weaken an inside sidewall just enough to ensure a blowout but not cause instant deflation.

 

Most tyre slashers use a pointed blade in a stabbing motion. Its a lot less effort than even dragging a Stanley blade sideways across the sidewall. Rubber grips, its why we dont all fall off the road.

 

That leaves us with a manufacturing defect or impact damage. Driving a short distance post deflation has undoubtedly caused a lot of the scrubbing type damage to the shoulder. I would have expected the sort of grinding/cutting of the sidewall between rim and road to be around the wall rather than radial radial but its not possible decide on the evidence of one pic if its impact damage.

 

Most punctures on fast roads are to the nearside rear tyre as debris gets thrown towards the nearside due to road camber and is flicked up off the road by the front wheel just in time to catch the rear.

 

 

[Borderer]

Hi George,

 

The tyre that blew was the rear offside. I was doing less than 30mph.

 

I've just got back from the tyre fitters. New tyre put on FOC, not question of any charge. Good service.

The pressures were rechecked too. They said that there was no indication of any malicious damage to the tyre, and there was no foreign body inside the tyre which could have caused the blow. They say that they cannot see what caused it. They will get back in touch with me when they hear from Continental.

 

I also emailed Continental on Sunday, but as yet no response.

 

So I now have my new rear tyre, and "fingers crossed" all will now be well.

[Brian Kirby]

Derek Uzzell - 2014-01-28 9:55 AM...............There may be a bit more to this, as Continental says that the ETRTO's standard relating to the "CP" suffix applies only to 8-ply-rated tyres. Nevertheless, it now seems that the "CP" suffix is purely an identifier, and does not prove that a tyre has defined technical attributes or that it has been tested differently from a tyre with a "C" suffix.

Thanks for this Derek. I'd forgotten that the XC Camping tyres pre-dated the CP designation.

 

As to what Michelin say in reply to your question, I find it difficut to know what to think! It may become clearer when/if the others reply. It seems strange that ETRTO should introduce a new tyre designation that, on Michelin's understanding, has no engineering definition. I accept that it would be a foolish manufacturer who added CP to any old tyre, but for now it remains difficult to understand what specific properties a "CP" tyre would have in addition to those of a "C" tyre. My present impression of what Michelin say is that it is more redolent of marketing than of engineering. How very odd!

[Derek Uzzell]

The ETRTO 'standard' business is a semantic misunderstanding.

 

There is no ETRTO technical standard for C-marked tyres, but there are ETRTO standards for the technical data shown on a C-marked tyre's side-wall.

 

The ETRTO has decreed that putting a "C" suffix on a tyre will indicate that a tyre has been designed for use on on a light-commercial vehicle (“C” = “camionnette)” and all the European tyre manufactuers conform to this when making 'white van' tyres.

 

All the ETRTO did in 2003 was define another suffix - “CP” (“CP” = “Camping Pneu”) but this has no direct effect on a CP-marked tyre's construction/performance characteristics.

[Brian Kirby]

I appreciate that ETRTO have (presumably) yet to respond to your question, but their website gives the impression that there are technical standards for C rated tyres as distinct from car tyres.

 

Purely rhetorical question, but how could a tyre be assessed as suitable to carry the CP rating, if there is no standard against which it may be judged? I'd expect there to be some statement of minimum qualifying characteristics. It'll be interesting to see what they have to say in due course.

[Derek Uzzell]

I'm pretty sure this (apparent) confusion could be resolved if the ETRTO's standards manual were freely available. Michelin(UK) plainly has a copy as they quoted the page number in the manual that refes to the "CP" marking, but the complete manual is not in the public domain.

 

There will be laid down procedures regarding how tyres should be tested (eg. how their Load Index and Speed Symbol data are obtained) and how their sizing and construction is described (eg. with "R" indicating a radial-construction tyre.)

 

However, there is no ETRTO standard that defines how a "C"-marked tyre must be constructed, how it must perform, etc. That's not how the system works.

 

Let's take a "215/70 R15" tyre, This descriptor indicates a radial-construction tyre for a 15"-diameter wheel and with a 215/70 profile. But it could be an SUV/car tyre, or a 'white van' tyre or a 'motorhome' tyre. It's the suffix that indicates the tyre's design-purpose - "C" = 'white van', "CP" = 'motorhome', no suffix = SUV/car, and it's the tyre manufacturer that decides that purpose not the ETRTO.

 

It's as simple as that - a "CP tyre" just means a commercial vehicle tyre for service on motor caravans and it's completely up to the tyre manufacturer as to what compound or construction are involved. ETRTO does not regulate how a tyre manufacturer should make a "CP"-marked tyre, it just defines the meaning of the "CP' suffix and standardises that meaning.

 

(It's not mandatory for tyre manufacturers marketing 'motorhome' tyres to "CP" mark them. Pirelli's "Chrono-Camper" range is just "C"-marked.)

[Brian Kirby]

It's intriguing! I wonder how many CP designated tyres are actually sold each year, compared the the number of plain vanilla C tyres? A very small proportion, I would guess. Repeated supply problems point to batch production rather than continual production, and it is clear that the tyre moulds differ - because the sidewall markings, and to some extent treads, differ. Stocking is complicated by the CP variation, as turnover relative to C tyres must be substantially lower. So even if, as I suspect, the actual cost of production is more or less equal to a C tyre, it seems the cost of distribution and stocking would be somewhat higher.

 

Playing on Camskill's website to compare Continental's range of 225/75 R16 light commercial/motorhome tyres, I got the following results:

 

Vanco 2 (C, 118R) C-C-2 £120.80. In stock.

VancoFourSeason (C, 121R) E-B-2 £143.00. No stock.

WinterContact 2 (C, 116R) E-C-2 £142.20. No stock.

VancoCamper (CP, 116R) C-B-2 £132.40. In stock.

 

So, for Continental, via Camskill, the premium for the Camper tyre is only £11.60 per tyre compared to the "standard" Vanco 2. (I wouldn't pay too much attention to the prices for tyres with no stock, because I don't think they sharpen their pencils until they have stock!) :-)

 

Perhaps the most interesting feature of the above, though, is how the fuel efficiency, wet grip, and noise ratings (and load ratings) vary for the same size tyre of differing type. Clearly there is more to these differences than simply changing the sidewall markings for marketing reasons. Both FourSeason and Winter are less fuel efficient, whereas the Camper has the same wet grip performance as the FourSeason, for example, while being more fuel efficient. It's just a shame they aren't a bit more forthcoming on the actual differences. Their claim, for their Camper tyre is:

 

For camper vans

- High safety reserves for camper van application.

- Robust construction for improved durability in rough camping environments.

- Reduced stopping distance on wet surfaces.

- Extra driving stability for rear-heavy camper vans.

- Long service intervals, as the tyres’ air pressure is held permanently above the minimum pressure.

 

What they don't say is how these claimed advantages are achieved. The first seems to imply reinforced construction. The second a tougher tread. The third a different compound. The fourth stiffer sidewalls. The fifth, that by specifying higher pressures under-inflation relative to load is less likely.

[Rayjsj]

Nice to hear that Borderers Tyre dealer fitted a new one FOC without any quibble. Thats the time when having a good relationship with your local dealer pays dividends. A bit of a 'lesson' to me, living out in the Retail 'Wilds' I have been tending to use 'the net' to buy things, because of the very low prices 'out there' compared to locally. Seems it is not always the best (or sensible) option. Ray

[Rayjsj]

Double Post, Thought : are Conti Vanco Campers and Michelin XC campers worth the extra costs ??

 

Brian and Derek seem to think so. Ray

[Derek Uzzell]

Brian Kirby - 2014-01-29 12:40 PM

 

It's intriguing! I wonder how many CP designated tyres are actually sold each year, compared the the number of plain vanilla C tyres?...

 

But don't overlook the Europe-wide motor-caravan market dominated by Fiat-based models.

 

Ignoring PVCs (that usually have "C"-marked tyres) a high percentage of new 'coachbuilt' Fiat-based motorhomes will be factory-fitted with "CP" tyres. Historically, those tyres would have carried the Michelin name but (according to a comment in a French motorhome magazine) the contract for supplying Fiat exclusively with "CP" tyres is now in the hands of Continental. Given the number of Fiat-based coachbuilt motorhomes sold annually (and assuming that Continental don't supply Fiat at cost!), this contract will be a nice little earner.

 

I'm not sure what other countries share UK motorcaravanners' preparedness to swap "CP" tyres for "C"-marked equivalents at tyre-replacement time. Certainly, in France, the view is held that a new camping-car SHOULD come with "CP" tyres on its wheels and it seems likely that this attitude would not change when tyre-replacement becomes necessary. Even in the UK, if a motorhome has "CP" tyres from new, there's a good chance that the owner will replace those tyres with "CP" ones. And, if the original "CP" tyres are Continental-made, there's a good chance that Continental-made "CP" tyres will be chosen as replacements.

 

I don't think there is any good reason to doubt the EU-labelling data provided by tyre manufacturers, but this is broad-brush information and (although better than no information) needs to be treated with care when comparisons are made. Exploring whether valid 'real world' comparisons could be made based on EU-labelling data was the objective of pro-mobil's 2013 test.

[Derek Uzzell]

Rayjsj - 2014-01-29 1:08 PM

 

Double Post, Thought : are Conti Vanco Campers and Michelin XC campers worth the extra costs ??

 

Brian and Derek seem to think so. Ray

 

I can't speak for Brian, but that's definitely NOT my view.

 

My 2005 Hobby was factory-fitted with Continental Vanco "C"-marked tyres. This pleased me considerably as 2004 Transit-based Hobbys had Michelin "XC Camping" 'motorhome' tyres that independent tests had shown to provide unspectacular on-road performance.

 

When I had the Hobby's tyres replaced I opted for Continental Vanco-2 "C"-marked tyres. Vanco-2 had succeeded the Vanco pattern and, as I had been satisfied with the original Vancos and could purchase Vanco-2 tyres locally at what I felt was a fair price I decided to stay with Continental products. Having weighed the Hobby and established that its axle loadings (well below a Vanco-2's design maximum) I felt no inclination whatsoever to fit "CP" tyres. If the pro-mobil test results had been available at the time I might well have chosen Hankook RA18, particularly if they had been cheaper than the Continentals. But that's water under the bridge...

 

The type of motorhome I'm interested in for my own use will be relatively compact (under 6.5m long) and no more than 3500kg in weight. If I replace the Hobby and the replacement motorhome comes factory-fitted with "CP" tyres I won't care. And if it comes factory-fitted with "C"-marked tyres, I also won't care. In the former case, if I were to replace the original tyres I might choose "C"-marked ones as replacements. In the latter case I would NOT choose "CP" tyres as replacements.

 

If a motorcaravanner is operating his/her vehicle near, at or beyond its axle-load maxima it would be sensible to have 'tough' tyres on it. In such cases "CP" tyres might be the best choice. If a motorhome has been factory-fitted with "CP" tyres and equivalent-size good quality "C"-marked tyres with a higher Load Index can be obtained as replacements and a financial saving be made, it doesn't seem unreasonable to opt for the "C"-marked tyres. This isn't a black-or-white issue - for absolute certainty become a Jehovah's Witness. ;-)

[Brian Kirby]

Derek Uzzell - 2014-01-29 1:47 PM

 

Brian Kirby - 2014-01-29 12:40 PM

 

It's intriguing! I wonder how many CP designated tyres are actually sold each year, compared the the number of plain vanilla C tyres?...

 

But don't overlook the Europe-wide motor-caravan market dominated by Fiat-based models.......................

I wasn't assuming the demand for CP tyres was negligible, Derek, just that compared to the number of light vans tyres sold they can be but a relatively small proportion of the market. After all, Fiat, Peugeot and Citroen dominate the motorhome market, with a few Mercs, VWs, and Ivecos to add. Then, there is the fact that most motorhomes tyres are changed on age, not mileage, whereas light vans tend to do far higher mileages and I would guess must use about a set of tyres per year. So, although thousands of CP tyres will be supplied per year, there must be many thousands more C tyres supplied per year.

 

Regarding Ray's implied question, I agree, it is horses for courses. Our first van was on Michelin XC Camping, our second on Continental Vancos (the front two replaced with VancoFourSeason, because I found the Vancos lacked traction on wet/greasy roads as they wore), and the present van is on Vanco Campers. I know the axle loads of the laden van, and that they are well within limits. So, when the time comes to change I will decide based upon what is then available, how it rates, and its cost. If I were buying now, I might well consider the Hankooks, as they seem to do at least as well as the others, but at lower cost. However, I never buy tyres on cost alone. I like vehicles that go when I want them to go, stop when I want them to stop, and go where I point them. Tyres have a lot to do with that! :-)

 

My real point was that if one sticks to the Continental range (to compare products from a single manufacturer) their Camper is not that much more costly than their Vanco 2 (10%), has a slightly more aggressive tread, better wet adhesion, and gives the same fuel economy and (approximately) noise level. So on that basis, I think the Vanco Campers are worth the extra £12 each cost for their improved performance. I suspect they would wear more quickly than Vanco 2s, but as wear is not usually the reason for changing motorhome tyres, it wouldn't bother me.

[lennyhb]

It's fine when you can choose the tyres yourself, but when you buy a new van you don't get much choice. With Hymer it's pot luck they will either be Vanco Camper or Michelin Agilis Camper, if they are not what you want it's expensive to change them.

My current van has Vanco Campers on it no complaints at all I would prefer the new van to have Michelin's but only because they have the M&S rating so I can be legal in Germany in the winter. Don't look forward to the harder ride as they run at 15 psi higher on the rear but like everything else in a Motorhome it's a compromise. I have arranged with my dealer if the van comes with Contis he will swap them for Michelin from another van.

[tonyishuk]

Pothole Damage ?

 

Rgds

[George Collings]

After another hard look at the pic and some heavy duty head scratching.

 

We now know the tyres direction of rotation as it the OS. Assuming it is debris on the road that caused damage it occured when the damaged area was virtually stationary relative to the vehicles direction of travel but travelling almost vertcally downwards. Not eveyrone appreciates that the hub of a wheel travels at vehicle speed while the bottom is stationary and the top is travelling at twice the vehicles speed.

Are you with me still.

 

A sharp edged object angled slightly against the tyre would have been driven upwards and probably inwards slicing into the sidewall explaining the rather sliced looking plies on what was the uphill side of the gash. I would heve expected the debris to have penetrated the tyre to some extent but might well have been ejected rearwards as the wheel continued turning. A good look at any mudflaps or even rear body skirts might reveal singns of impact or abrasion.from the debris.

 

Rubber is tough as the proverbial but I remember seeing a tractor tyre penetrated clean through the thickest part of a tread lug by the broken off end of the flymo type blade of the mower its was powering.

 

T o my mind the odds are about 4:1 on debris damage.

[Derek Uzzell]

lennyhb - 2014-01-29 5:41 PM

 

It's fine when you can choose the tyres yourself, but when you buy a new van you don't get much choice. With Hymer it's pot luck they will either be Vanco Camper or Michelin Agilis Camper, if they are not what you want it's expensive to change them.

My current van has Vanco Campers on it no complaints at all I would prefer the new van to have Michelin's but only because they have the M&S rating so I can be legal in Germany in the winter. Don't look forward to the harder ride as they run at 15 psi higher on the rear but like everything else in a Motorhome it's a compromise. I have arranged with my dealer if the van comes with Contis he will swap them for Michelin from another van.

 

As I said earlier, my understanding was that, currently, all Ducato 'chassis' leaving the Italian SEVEL factory with "CP" tyres on their wheels would have been fitted with the Continental Vanco-Camper pattern. This may be wrong, but if your new Hymer comes wearing Vanco-Campers and your dealer swaps them for Michelin Agilis Camping tyres at your request, it might be wise for you to check the manufacturing date of the Michelin tyres.

 

As you rightly say, Agilis Camping tyres are M+S marked, but I don't understand your comment that "...they run at 15 psi higher on the rear...".

 

The Vanco-Camper and Agilis Camping tyre-ranges both target the motorhome market and (with one Vanco-Camper size exception) are all "CP" marked. As the ETRTO recommends that "CP" tyres fitted to the rear wheels of motorhomes be inflated to a high pressure, all Vanco-Camper and Agilis Camping tyres should logically be capable of being inflated to 80psi. This is indeed so and the Vanco-Camper exception (215/75 R16 size and "C"-marked not "CP") has a design capability of being inflated to 6.0bar (88psi).

 

A significant difference between Michelin and Continental regarding "CP" tyres is not so much the tyres themselves, or their ultimate inflation-pressure, but how each company views the ETRTO's rear-tyre inflation-pressure recommendation.

 

If an owner of a motorhome fitted with Agilis Camping tyres weighs his/her vehicle and asks Michelin for advice on the inflation-pressures that would be appropriate to the measured axle-loadings, Michelin will advise 80psi for the rear tyres irrespective of the measured rear-axle loading figure. Continental, on the other hand, are prepared to provide advice on a Vanco-Camper rear-tyre pressure appropriate for a stated axle-loading. Nowadays Michelin will ALWAYS recommend 80psi for their Agilis Camping "CP" tyres when fitted to a 'single wheel' rear axle, but Continental may well advise a different pressure.

 

The inflation-pressure to axle-load 'graphs' for Vanco-Camper tyres can be viewed in Continental's Technical Databook (example here)

 

http://www.bushtyres.co.uk/library/pdf/conti-technical-data-book.pdf

 

The Van section begins at page 82 and it should be apparent from the listings that Continental's "CP" tyres can be inflated to 5.5bar (80psi) or (in some cases) higher.

 

Although Promobil's 2013 tyre report did not compare Continental's Vanco-Camper with Vanco-2, it did compare Vanco-Camper with Michelin's Agilis Camping. Out of a maximum overall 'score' of 10, Vanco-Camper was given 7.9 while Agilis Camping got 7.0.

 

Besides Agilis Camping, two other M+S-marked tyre patterns were tested - Hankook's Vantra LT RA18 and a China-manufactured tyre "GT Radial Maxmiler EX". These scored 9.0 and 8.3 respectively. The cost of a tyre was not factored into the scores, but these were quoted as

 

Vanco-Camper & Agilis Camping - €138

Hankook Vanta LT - €95

GT Radial Maxmiler - €76.50

 

An Italy-manufactured tyre "Marangoni E-Comm" was priced at €98 and scored lowest (6.2).