tyre pressure reassurance

[naittaw]

I have just been in touch with Continental re Vanco2 Tyre Pressures. They have told me that, for front axle - 1560Kg : rear axle - 1740Kg, the pressures should be 47psi and 54psi. The tyres are 215/70/R15C/109R. These pressure are much lower than anything I've used before and make me suspicious. I'd be grateful for reassurance (or otherwise) from others.

[Brambles]

Hi, Yep! look about right. Have checked my tyre pressure chart and for the weights you have given they look correct.

Michelin (I know you are conti) usually add 10% to front pressures to allow for weight shift forward when braking, as Motorhomes tend to be top heavy.

I would suggest if you are top heavy(over head cab and lots of load high up) you add 10% all round because of side sway of vehicle, but sounds like with your weights you are a low profile or even a van conversion so pressures are then correct.

 

If you are ever likely to have additional weight, or are in dount as to max weight your are better to have a sligtly higher pressure than be too low.

 

I assume you asked for pressures for your vehicle normally laden and not unladen, otherwise you will have to load it up as you normally do and go get it weighed and ask again.

[naittaw]

Thanks Brambles. That's reassuring. The weights quoted are fully laden with passenger and driver. I have been on Michelin Campers with a front pressure of 55psi and rear of 60psi. Hence my request for confirmation. Thanks again.

[spospe]

naittaw

 

I used to have a Duetto built on the Transit with the 2.5DI engine. This vehicle had a max weight of 3500Kg and used Continental Vanco tyres. The quoted pressures were 41 psi front and 54 psi rear for the non-turbo version and 45 psi front, 54 psi rear for the turbo.

 

I ran the 'van for just on 80,000 miles over 6 years and had no problems at all, the average tyre life was 32,000 miles.

 

Hope that this is of some help ........... Michael

[rupert123]

naittaw - 2009-02-27 11:09 AM

 

I have just been in touch with Continental re Vanco2 Tyre Pressures. They have told me that, for front axle - 1560Kg : rear axle - 1740Kg, the pressures should be 47psi and 54psi. The tyres are 215/70/R15C/109R. These pressure are much lower than anything I've used before and make me suspicious. I'd be grateful for reassurance (or otherwise) from others.

 

I run same tyre, make and size, and for 1250kg front 1750kg rear they gave me 44psi and 68psi.

[Brambles]

I think 68psi is the absolute max fully laen pressure for the Vanco 15 inch, so I a bit high I think. It sis also above what the max weight is teh axles wil take. So a misnoamer there.

 

Might be worth asking again with your unladed weight and say 10% over max laden and seeing what figures they come up with, if you feel concerned. You can then plot more or less a straight line graph so any intermediate weights you can approximate.

[mick noe]

continental vanco on my van [compass drifter 410 fiat ducato 1997] recommended pressures from continental front up to 1685kg 51psi rear up to1780kg 54psi

[Brian Kirby]

It is agood idea to get advice from the tyre manufacturer on the correct tyre pressures for you axle loads.

However, do bear in mind that you are departing from the handbook recommended pressures, often confirmed in a manufacturer's sticker on your vehicle.  Do also bear in mind that the load in the vehicle varies as you travel, and so the axle loads, so it is wise to add an upwards margin.

Having made the necessary allowance for load fluctuations, send the axle loads to the tyre manufacturer in writing, and ask for his written response.  Do not accept, and proceed on, verbal advice.  Should you be challenged by the police, or should your tyre pressures be checked after an accident, and the pressures be found to be lower than the vehicle manufacturer's recommended pressures, you may be at a considerable disadvantage when blame is apportioned.  You may also have insurance trouble as, without evidence that you acted responsibly and on expert advice, you may be held not to have manitained your vehicle properly, which is a basic requirement of your insurance.

This is not intended to put anyone off: I have done the same and have written confirmation from Continental for the pressures at which I run our van.  The vehicle is more stable, and more comfortable, at these lower pressures but, above all, I can show why I am using them if I have to.

[naittaw]

Brian, the trouble is that the manufacturer's hanbook and stickers refer to the base vehicle (and presumably its intended original use), in my case Peugeot Boxer, and don't seem to be immediately relevant to the Motorhome conversion. In addition the converters don't seem to want to take responsibility, in my case Autosleeper. This is why we get repeated advice on this forum to send actual axle weights from a weigh bridge to the manufacturer. I started this thread to get some reassurance that the advice I got was correct. The doubt arose for 2 reasons. First because the previous advice from Michelin for their tyres which I have been using up to now, asked for a higher pressure and second because I did get wrong figures from Michelin on first contact with them, and they had to correct it when queried. So like everything else the advice you get is subject to human error, and if it looks dodgy query it.

[rupert123]

Brian your advice re tyre manufacturer seems good but if you read posts above you will see both myself and Alfred did just that and despite having nearly the same load on rear axle got very differant recommendations. I have just emailed them again as this is all a little worrying.

[naittaw]

Rupert, let us know the result of your further enquiry. I presume you have a single rear axle. Pressures are different for single and double, though whether higher or lower I wouldn't know. Alf.

[rupert123]

naittaw - 2009-02-28 11:41 AM

 

Rupert, let us know the result of your further enquiry. I presume you have a single rear axle. Pressures are different for single and double, though whether higher or lower I wouldn't know. Alf.

 

OK Alf, they took about ten days to reply last time. Mine is single axle.

[alf]

In November I was sent these tyre pressures bi Michelin for Agilis 81

215 / 70R15C

 

 

"As a guideline from the axle weights that you have supplied the pressures for those weights are as follows:-

 

Actual Weights

Front axle load of 1560kg the pressure should be – 55psi (pounds per square inch)

Rear axle load of 1565kg the pressure should be – 50psi (pounds per square inch)

 

Plated Weights

Front axle load of 1750kg the pressure should be – 60psi (pounds per square inch)

Rear axle load of 1850kg the pressure should be – 60psi (pounds per square inch)

 

 

We have allocated your message the reference number indicated above. If you need to contact us again regarding your message, we would be grateful if you could include the reference number.

 

Once again thank you for your interest in Michelin."

Regards Alf

 

 

[Uncle Bulgaria]

I received similar advice from Michelin regarding my XC Camping tyres in the form of a letter attached to an email. I carry a photocopy of the email and letter in the vehicle. I run at 58 front (which includes Michelin's 10% suggestion) and 64 rear. These two values correspond to Michelin's advice for the plated maximum axle wieghts of 1850Kg and 2060Kg. These also correspond to the figures given in the Knaus users manual with the vehicle for the motorhome when fully laden. I actually run at around 1680Kg front and 1750 Kg rear, so I have about 170Kg spare weight capacity on the front axle and 310Kg on the rear. I find dropping the pressures to match the actual axle weights (weighbridge measured) makes negligible inprovement in the ride. The spare weight capacity more than covers for variations in l oading, especially putting the usual 100Kg of wine in the garage (part compensated by emptying the fresh water tank) for the trip home from Calais!

 

Richard.

[Chudders]

Have alook at this web site www.tyresafe.co.uk this is the tyre councils website with loads of useful info including a section specifically for motorhomes. Gives generalisations on tyre pressures for given axle loads as well as other info.

Regards, dave

 

[Brian Kirby]

naittaw - 2009-02-28 10:11 AM Brian, the trouble is that the manufacturer's hanbook and stickers refer to the base vehicle (and presumably its intended original use), in my case Peugeot Boxer, and don't seem to be immediately relevant to the Motorhome conversion. In addition the converters don't seem to want to take responsibility, in my case Autosleeper. This is why we get repeated advice on this forum to send actual axle weights from a weigh bridge to the manufacturer..........

If Autosleepers have re-plated your van to a higher figure than was permitted by Peugeot, then Autosleepers should have removed, or replaced with accurate ones, the original Peugeot tyre pressure stickers.  Similarly, if Autosleepers have increased either the individual axle limits, or the overall MAM, the new limits, and the corresponding tyre pressures, should be stated the their handbook, with an instruction to disregard the pressures stated in the Peugeot owners handbook.  If they have done neither, shame on Autosleepers! 

Since the UK does has not (I believe still) adopted European type approval procedures, I guess Autosleepers can try to sidestep its obligations.  Under the European procedure, Autosleepers, were they to alter the axle, or overall, loadings of the vehicle, would be obliged to take responsibility for their actions by issuing the correct information to the vehicle owner.  They would then become legally responsible for the consequences of so doing.  Unless I am misunderstanding you, Autosleepers do seem to have been rather irresponsible in what they have done with your van.

If, however, you mean that the original Peugeot weights and pressures are higher than you think necessary for your van, why should Autosleepers reduce these?  All they would achieve is to limit their market by removing potential payload.  To reduce the pressures below recommended has to be the owner's decision: the manufacturer will set limits to ensure that tyres, wheels, suspensions, brakes etc are all capable of surviving occasional overload, which is not that uncommon, without catastrophic failure. 

The owner who knows, within reasonable limits, what his actual axle loads will be, can then reduce the tyre pressures - on advice from the tyre manufacturer - to appropriate values, and benefit from improved ride comfort, and sometimes improved directional stability, braking, and traction.  The others can just continue shaking their stoppings out!  :-)

However, if you take this route, do be sure your loads don't creep up, leaving your tyres under-inflated.

[Brian Kirby]

rupert123 - 2009-02-28 10:53 AM Brian your advice re tyre manufacturer seems good but if you read posts above you will see both myself and Alfred did just that and despite having nearly the same load on rear axle got very differant recommendations. I have just emailed them again as this is all a little worrying.

You are wise to have done so, Rupert.  It does seem there is a error, or a misunderstanding, over your rear axle load and/or the appropriate pressure.  I think they have quoted you the maximum permissible, rather than the load appropriate, pressure.  However, whereas that may result in a harsh ride, it will not affect safety.

Not directed at your query, but while posting, there is a danger in reeling off, on this forum, individual axle loads and the pressures quoted against them for various base vehicle, conversions, tyre/rim sizes, and tyre makes.  It is not safe to assume that because one owner's vehicle has axle loads of given values, and has been recommended pressures to suit, that those pressures will necessarily be appropriate for someone else's van, however similar it may seem. 

There is quite a disparity between the pressures quoted by Michelin and Continental, for example, for similar sized tyres and loads.  Added to this, many people do not read carefully, and may not spot that the wheel, or rim, type/size is not as theirs.  Many more people read these threads than post, and it is possible that, however foolish it may be, one of the "silent ones" will take the data quoted on here as a recommendation appropriate to them, and proceed without making the proper checks.  If the result were under-inflated tyres, the consequence could be disastrous. 

The only safe advice is to consult the tyre manufacturer, quoting the actual weighbridge values from weighing the fully laden van, but also to quote the maximum permissible axle loads from the VIN plate.  The tyre manufacturer should give the pressures appropriate to both sets of loads, so enabling the maximum comfortable pressures to be established, as well as the pressures appropriate to actual load.  In my (limited) experience, Michelin are better at this than Continental, seeming to have much subtler load/pressure tables.

[naittaw]

Brian,

I agree with much of what you say, especially the bit about not taking what you read on the forum to be specific to you especially if you have different vehicle or different tyres. However, the Autosleeper handbook refers the owner to the base vehicle handbook for tyre pressures. The base vehicle handbook does not specify pressures but only warns about under-inflation. The door pillar sticker says 79.5psi both front and rear.

The base vehicle tyres would not be Michelin Campers, and I now propose to change to Continental Vanco2. So for both the previous Michelins and the pending Continentals I have consulted each of the Tyre Manufacturers having passed over a weighbridge, fully laden for a continental holiday. The discrepancy between Michelin and Continental prompted me to check with others who might also be on the same Vanco2 Tyre. I did not really intend to open a great can of worms on a subject which has been well covered on the forum before. So apologies to those who are bored by it, or confused by it, but thanks for your interest. Alf W.

[Brian Kirby]

I have no grounds to question what you say, but I'm amazed if the Boxer handbook says nothing about the pressures.  Is there nothing at the back of the book, in a bit about tyre sizes?  Our previous Ducato, and our present Transit, both gave/give details of tyre sizes and the appropriate pressures, even quoting the Michelin Camping tyre pressures.  Your 79.5psi sounds like a Camping tyre pressure to me, so I would assume the Peugeot sticker is relevant to a Camper chassis and the original tyres.

Various claims have been made for the Vancos but, in all honesty, although I have not tried both on the same van, (previous van on Michelin Camping, present on Continental Vancos) I don't think they are that different on the road to the Michelins.  Both are harsh at max pressure, but much better when at "correct" pressure, both tend to "tramline" at max pressure, but not at "correct" pressures, both are compounded for mileage and toughness over grip and comfort, and neither gives much grip on wet grass!  Either Vanco Camping, or Agilis Camping would, I think, be equally satisfactory and, in retrospect, I think I would just buy on price and availability.

[naittaw]

Thanks Brian, I'm equally surprised but having checked again there is no mention of tyre sizes or pressures in the Boxer handbook. The index refers the owner to two pages, both of which warn about under inflation, damage from kerb collision and inflating when cold, but there is a great lack of technical detail. The technical tables contain details of dimensions, weights and loads but not tyre sizes or pressures. It's also interesting that the Motorhome section of the Tyresafe website does not quote a tyre size of 215/70/15 in the Light Commercial Pressures table, and in the Camper tyres table it quotes the size but axle weights begin at 1795Kg for front and 1597Kg for rear ! I think I'll start with Continental advice + 10% and see how it feels. Thanks to everyone for their contributions.

[alf]

As a matter of interest what type and make is your motorcaravan

Regards

Alf

[naittaw]

Autosleeper Ravenna - on Boxer 330 LX MWB : year 2003 : 2.8 tdi

[Derek Uzzell]

naittaw

 

Tyres intended for similar purposes and having the same size, load-carrying capability and 'ply-rating' will normally require a similar inflation pressure to support safely the same axle-load.

 

Hence, if a Continental Vanco-2 215/70 R15C 109/107R tyre requires 47psi or 54psi for axle-loads of 1560kg or 1740kg respectively, then a Michelin XC Camping 215/70 R15C 109/107Q tyre will require those pressures too. (This is confirmed from my 2004 Michelin Technical Handbook.) Logic dictates this shall be so, otherwise alternative makes of tyres factory-fitted as original equipment by vehicle manufacturers would require their own manufacturer-specific inflation pressures to be quoted in vehicle handbooks.

 

Although Michelin's specialised XC Camping tyre has a design capability to be operated beyond its sidewall-marked load limit (in this case 109=1030kg maximum load per tyre), when an inflation pressure up to 80psi will be essential, up to 1030kg tyre-load (ie. 2060kg single-wheel-axle load) XC Camping's inflation-pressure-to-load 'graph' is near enough the same as that of Michelin's general purpose, light commercial vehicle Agilis 81 215/70 R15C 109/107R tyre. Vanco-2 is just another 'van' tyre and there is no good reason to suppose that its pressure-to-load graph will differ significantly from that of Michelin's Agilis product.

 

In this instance, although Continental's advice may be correct for your Ravenna's weighed axle-loads, the motorhome may well feel a mite 'soggy' as higher pressures have been employed previously. Should that prove to be so, then, as Brambles suggests, increasing the pressures somewhat (I'd suggest remaining at 55psi(F)/60psi®) could make driving more pleasant. The important thing is always to err on the high side of 'correct', never on the low side.

 

Agonising over the odd PSI is unprofitable. According to Continental, the European benchmark for a 'cold' tyre is 20°C, so, if you inflated a motorhome tyre to 55psi on a frosty February day and it lost absolutely no pressure over the next 3 months, on a warm May afternoon you'd find the pressure would be at least 60psi.

 

(As Brian emphasises, there is a very real danger of confusion if tyre inflation-pressure comparison/advice is offered and differences in the vehicle, tyre size/specification, axle-loadings, etc. are not taken into account.)

[naittaw]

Derek, thank you very much indeed for that. Having read your previous responses to posts on this subject I'm glad to have your input which I find very helpful indeed. Many thanks.

[rupert123]

Derek while I would agree with the first half of your post I cannot with the second. If any tyre manufacturer sends you a letter or email with the tyre pressures they recommend then you have to go with that not apply your own interpretation on it. I also see no confusion, why would anyone take the figures given to someone else as a reason to copy them. This is simple, weigh your van give the tyre people the figures, they give you the answer, not complicated at all. Now when the question was first asked it happened that my rear axle loading and tyre size was the same as Alfs but the pressures given were very differant. Because of this I have asked again, everyone makes mistakes. If Conti come up with same figures then would suggest Alf asks again. If in doubt ask the tyre people again do not take any figures quoted on a forum as the right ones, your insurance company and the police certainly will not.