Fiat ducatto 2.3

[bigjohnthecat]

Burstner sovereign 2015 3.5 Tons what is the correct tyre pressures please?

[Keithl]

What are your individual axle weights when fully loaded ready for a trip and what make and size of tyres do you have fitted?

 

Keith.

[bigjohnthecat]

Hi Keith they are Michelin agilis but no idea of the axel weights.

Cheers john

[Keithl]

The best you can do without true axle weights is to set the pressures for the maximum allowable axle weights as stated on your VIN plate.

 

Find the size of your tyres and their load rating from the tyre sidewalls and the maximum axle weights from lines 3 and 4 of your VIN plate and then we should be able to help with suitable pressures.

 

Keith.

[bigjohnthecat]

Hi Keith many thanks for that I will check tomorrow.

Cheers John

[Keithl]

John,

 

Once you have the figures look up your tyre size on page 5 of the TyreSafe MH leaflet here (note the difference between C, commercial and CP, camping tyres)...

 

http://www.tyresafe.org/wp-content/uploads/2015/12/motorhome-leaflet.pdf

 

and then against your max axle loads read up to the recommended pressures.

 

This should give you suitable pressures until you can get your MH weighed and calculate more exact pressures.

 

Keith.

[Dickybeau]

What version of the Sovereign do you have? I have a Viseo Sovereign 700i. According to the manual recommended tyre pressures are Front : (215/70 R15 CP) 5.0 bar. Rear: 5.5 bar. The Sovereign version came fully loaded with extras and we found we were constantly on the limit when on holiday and have upgraded the weight capacity on our van to 4000kg. I’m still on 15inch wheels but with 225/70 R15 tyres which carry a heavier loading. The sidewall tells you that the loading value (112) is only reached when the tyre is at a certain pressure (think it’s 5.5bar but can’t remember right now).

 

Worth looking at the Bürstner website to see if you can download the manual for your van.

[Keithl]

Dickybeau - 2019-04-17 10:32 PM

 

... I’m still on 15inch wheels but with 225/70 R15 tyres which carry a heavier loading. The sidewall tells you that the loading value (112) is only reached when the tyre is at a certain pressure (think it’s 5.5bar but can’t remember right now).

 

 

Dickybeau,

 

According to the TyreSafe MH leaflet the 5.5 bar pressure ONLY applies to rear tyres when the vehicle is rear wheel drive! (see Note 1 against Single Rear)

 

For FWD vehicles ALL tyres should have the same pressure and for the maximum axle loading of 2,240 kg on your 225/70 R15 CP tyres this is at a pressure of 4.75 bar or 69 psi.

 

All data is from the TyreSafe MH leaflet linked to above.

 

Keith.

[Dickybeau]

Keithl - 2019-04-17 10:43 PM

 

Dickybeau - 2019-04-17 10:32 PM

 

... I’m still on 15inch wheels but with 225/70 R15 tyres which carry a heavier loading. The sidewall tells you that the loading value (112) is only reached when the tyre is at a certain pressure (think it’s 5.5bar but can’t remember right now).

 

 

Dickybeau,

 

According to the TyreSafe MH leaflet the 5.5 bar pressure ONLY applies to rear tyres when the vehicle is rear wheel drive! (see Note 1 against Single Rear)

 

For FWD vehicles ALL tyres should have the same pressure and for the maximum axle loading of 2,240 kg on your 225/70 R15 CP tyres this is at a pressure of 4.75 bar or 69 psi.

 

All data is from the TyreSafe MH leaflet linked to above.

 

Keith.

 

Keith,

The tyre sidewall says that it is only rated at 112 with tyre pressure at 5.5 Bar. Despite what Tyresafe recommend, I’m going to continue to follow the advice on the tyre sidewall. My Bürstner manual has a table of tyre pressures that are TUV approved (otherwise they couldn’t appear in the manual) which give different tyre pressures front and rear except where 16 inch wheels are used. In that case tyre pressures are equal on the van if there is no tandem axle.

The advice in the leaflet confirms that the tyre pressure affects the load of the tyre. The tyre advice from the tyre manufacturer advises 5.5 Bar for the required tyre loading. The advice from the professional engineer who advised on my weight upgrade was a tyre loading of 112. Given all that information I wonder if Tyresafe needs to change its advice or if the tyre manufacturer needs to alter its warning on the tyre sidewall?

[thebishbus]

Run them too low and the sidewalls will craze prematurely . I would run them at 70/75 psi.

Brian B.

[Billggski]

Don't guess. Some of the advice you can be given is just opinion. Check.

Take it to a weighbridge, my local haulier charges £7 for both axles and total weight.

It's the rear axle that gets overloaded, even with front wheel drive.

The 5.5 bar, 80psi, guide is for camping car tyres only. Marked CP, and will be what manufacturers recommend for the rear to cover themselves.

When you know what the axle loads are in full camping trim, full fuel, water, clothes, pots and pans, then you can look up the tyre pressures needed for your make and spec of tyre.

Don't guess, it's your only contact with the road.

[Brock]

Bigjohn I doubt anyone can give you a definitive answer to your question. For example, Hymer gave me front and rear tyre pressures which are different to those Alko gave me which are different to the ones Michelin gave me which are different to the ones I received when I keyed the axle loadings into:

 

https://www.tyresafe.org/check-your-pressures/motorhomes/

 

I can use a rolling roadaxle weighing machine at a firm that makes and calibrates weighbridges for the DVSA and others. I can then get the tyre pressures for the readings from Michelin. In March 2017, the DVSA advised me [the advice is somewhere in a post of mine around that time],

 

"... the vehicle should be weighed with a full tank of fuel full tank of water and all that you would normally carry but we would recommend that a tolerance is used to allow for the items you may pick up on route the different foods you may carry etc. If stopped by any enforcement agency consideration would be taken especially if you have a recent weigh bridge ticket that shows you have done everything to comply. We are aware of the variations between weigh bridges but we will not tolerate people that have checked the weight but continued even though the weight was clearly over the maximum permitted weight for that vehicle."

 

I do not know whether that advice is still DVSA's approach but it strikes me as being reasonable.

[Dickybeau]

Hopefully I can load this picture that shows the relationship between tyre pressure and loading on my CP tyres 80psi is 5.5 Bar I think

[Dickybeau]

Can’t get a picture small enough to load but the tyre wall on my CP tyre (Michelin Agilis 225/70 15) says “112Q AT 80PSI”

[weldted]

Boxer 2.2 Elddis Aspire, uprated from 3700 kg to 3850, required semi air suspension and replaced 215/70 r15 with 225/70 r15 Michelin Agilis CP. MAX REAR AXLE 2240. Advice from Michelin 5.5 bar all round. Although front axle is not carring the same weight when braking downhill or heavy braking on level the weight transferred to the front axle can temporarily exceed its permitted rating, hence the recommendation to have 5.5 all round.

[Derek Uzzell]

Keithl - 2019-04-17 10:43 PM

 

Dickybeau - 2019-04-17 10:32 PM

 

... I’m still on 15inch wheels but with 225/70 R15 tyres which carry a heavier loading. The sidewall tells you that the loading value (112) is only reached when the tyre is at a certain pressure (think it’s 5.5bar but can’t remember right now).

 

 

Dickybeau,

 

According to the TyreSafe MH leaflet the 5.5 bar pressure ONLY applies to rear tyres when the vehicle is rear wheel drive! (see Note 1 against Single Rear)

 

For FWD vehicles ALL tyres should have the same pressure and for the maximum axle loading of 2,240 kg on your 225/70 R15 CP tyres this is at a pressure of 4.75 bar or 69 psi.

 

All data is from the TyreSafe MH leaflet linked to above.

 

Keith.

 

15 years or so ago it used to be suggested in Michelin’s Technical Handbook that, for motorhomes fitted with Michelin "XC Camping” tyres and operated in Continental Europe, just the rear tyres should be inflated to a 5.5bar/80psi pressure.

 

Later on there was argument over whether that pressure recommendation applied only to RWD vehicules (though, with hindsight, it has to be asked why that should ever have been the case).

 

Michelin’s on-line Tyre Safety Guide now advises as follows:

 

MOTORHOMES:

 

Motorhomes require tyres are that are adapted to their conditions of use.

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.

 

Fitting tyres that are not adapted to this type of use could lead to:

- poor handling (roll, pitch, yaw, difficulties in road holding)

- in difficult or severe conditions, premature deterioration of tyre components,

such as the crown, which could lead to a rapid deflation.

 

In use: check and adjust if necessary tyre inflation pressures monthly and before

any long journey. Under-inflation can be dangerous: for example,

for the tyre size 225/70R15 Camping CP, an under-inflation of 0.5 bar/7.2psi

(11%) is equivalent to an overload of around 100 kg per tyre.

 

Overloading (even temporarily) or poor vehicle load distribution can cause

premature deterioration of vehicle components and/or tyres and thereby cause

damage to persons or property”.

 

If a change of tyre size is foreseen, a tyre of an equivalent overall diameter

should be used and the original load index and speed symbol should be

respected (speed and load ratings must be equal to or greater than the

original tyres). It is recommended that a tyre professional is consulted for this

operation.

 

If the vehicle is parked for a long time, do not leave the tyres under inflated,

and always make sure that the inflation pressures are correct before next

using the vehicle. Protect tyres from UV radiation, e.g. from sunlight, and use

axle stands to avoid tyre contact with cold winter surfaces (concrete, stone ...).

 

Have the condition of the tread and sidewall checked regularly (for impact

damage, cuts, cracking etc...) as well as the condition of the wheels and valves,

by a professional.

 

NOTE: For tyre inflation pressures above 4.5 bar (450 kPa), metal valves appropriate to

the pressures must be used.

 

It will be seen that the ETRTO stricture relating to the 5.5bar rear-tyre pressure does not discriminate between FWD or RWD motorhomes. The stricture does however specify that the rear axle be “single fitment” (ie. has a single wheel on each end of the axle) so it won’t apply to a motorhome that has a ‘twinned-wheel’ rear axle (ie. has a pair of wheels on each end of the axle) and only RWD motorhomes will have a ‘twinned wheel’ rear axle.

 

A tyre with a load-index of 112 indicates that it is capable of supporting a load of 1120kg at a defined pressure (in Dickybeau’s case 80psi/5.5bar), but it stand’s to reason that, if the ACTUAL load on that tyre is WELL BELOW 1120kg, choosing to inflate the tyre to 80psi will be unnecessary (and will result in a harsh ride and quite possibly uneven tread wear).

 

As has been advised here countless times, if you want to know SUITABLE pressures for your motorhome’s tyres, you’ll need to identify the tyres’ EXACT specification (make, tyre-name, size, load/speed identifiers) and then obtain the motorhome’s axle-loadings by weighing each axle when the vehicle is in its normally-loaded condition.

 

 

[Dickybeau]

Thanks for that Derek. The main reason for my changes to tyres have been weight loads on my van. At 3500kgs I was only a few kilos away from that limit when loaded for a continental trip. That didn’t include water in any tank but a full tank of fuel. Since I use French Aires and German equivalent most of the time, I need to carry water for basics like washing up and cleaning behind my ears or whatever the wash facilities in the van are for. It was reasonable to assume that I was, unconsciously overloading my van from time to time in my travels. At the same time I was balancing items like cases of wine v dog food. A fine balance you might agree. I simply want to make sure my van is safe to drive and that my insurance remains valid. While I haven’t yet had my axles weighed in the new form,I fully intend to do so before I go on holiday once I am loaded. I have also added wireless TPM which I find immensely reassuring since I have been accustomed to that feature on motorbikes for many years. my problem right now is finding a weighbridge owner that knows how to weigh the van properly after my normal place closed down on retiral of the proprietor.

 

At the moment my tyres are at 5.5 Bar and will remain at that until I have a more accurate weight measurement. I must confess not to notice if the van has a harsh ride. I can’t tell what is due to crappy roads and what is due to tyres. I’m going to be checking wear rates though and measuring tread depth as we go.

 

[Derek Uzzell]

Once you’ve weighed your Burstner you can seek advice from Michelin about tyre inflation pressures.

 

Michelin strictly follows the ETRTO’s diktat that CP-marked tyres fitted to a motorhome's ‘single fitment’ rear-axle be inflated to 5.5bar irrespective of that axle’s maximum authorised axle-loading or the actual load that the axle carries. So, whatever you tell Michelin about your Burstner’s rear-axle weight-wise, Michelin will only provide a 5.5bar inflation figure.

 

However, as the ETRTO does not stipulate the inflation pressure to be used for CP-marked tyres fitted to a motorhome’s front-axle, Michelin is prepared to offer advice based on a front-axle weight (maximum authorised axle-loading or the actual load that the front axle carries) and provide an inflation pressure suitable for that weight.

 

From what you’ve said, it’s quite possible that you’ll need 5.5bar for your Burstner’s rear tyres, but you shouldn’t need that pressure for the front tyres.

 

My Rapido 640F motorhome is smaller and lighter than yours and I don’t load it heavily. It carries a Rapido data-plate advising that its tyres (215/70 R15CP Michelin “Agilis Camping”) be inflated to 5.0bar (front) and 5.5bar (rear) when the motorhome is FULLY LOADED, though what this actually means is not defined. I briefly tried those pressures, but the ride was harsh and the steering unpleasantly light. Now I use 4.5bar (front) and 5.0bar (rear), which still results in a firm ride but gets rid of some of the steering lightness.

[Dickybeau]

I’ve noticed that the rear is less harsh now I’ve replaced the rubber bump stops with airbags. The air bag pressures are far more problematic than tyre pressures IMO. Minimum is 0.5 bar as recommended by the supplier/ manufacturer. Maximum is 3.0 Bar. My loading is, generally speaking, reasonably even, though I still have some experimentation to be done.

[Laurence]

Derek Uzzell - 2019-04-20 8:51 AM

 

So, whatever you tell Michelin about your Burstner’s rear-axle weight-wise, Michelin will only provide a 5.5bar inflation figure..

 

I didn't even get that from Michelin. My previous MH had Continental tyres and the firm could not have been more helpful I gave them FAW, RAW and AUW (you see my military background there, all I need is a black patch and a space for a Chalk number on the front) and they sent me a wealth of useful information including the exact tyre pressures I should use.

 

The Laika came with Michelin Agilis 225/75 R16 CP 116Q, so after visiting a weighbridge I went through the same exercise with Michelin and I got standard response No 8 after a bit of a wait - consult the Fiat handbook; consult Laika; what does your mother say? All absolutely useless and unhelpful - a corporate exercise in sloping shoulders.

 

So I play it safe, I run both axles at 5.5 bar and so far that seems to have worked. As for the ride, well, I don't expect it to be that comfortable - it's a van chassis running at constant high weight.

 

Regards,

[weldted]

Re your air bag pressures? When I fitted mine I checked the height between the rear jacking points and ground level with the van empty, loaded it to its max 3850 then pumped the airbags up to achieve the same ground clearance. This was achieved at 1.9 bar and gave a comfortable ride.

[Derek Uzzell]

Laurence - 2019-04-20 6:45 PM

 

Derek Uzzell - 2019-04-20 8:51 AM

 

So, whatever you tell Michelin about your Burstner’s rear-axle weight-wise, Michelin will only provide a 5.5bar inflation figure..

 

I didn't even get that from Michelin. My previous MH had Continental tyres and the firm could not have been more helpful I gave them FAW, RAW and AUW (you see my military background there, all I need is a black patch and a space for a Chalk number on the front) and they sent me a wealth of useful information including the exact tyre pressures I should use.

 

The Laika came with Michelin Agilis 225/75 R16 CP 116Q, so after visiting a weighbridge I went through the same exercise with Michelin and I got standard response No 8 after a bit of a wait - consult the Fiat handbook; consult Laika; what does your mother say? All absolutely useless and unhelpful - a corporate exercise in sloping shoulders.

 

So I play it safe, I run both axles at 5.5 bar and so far that seems to have worked. As for the ride, well, I don't expect it to be that comfortable - it's a van chassis running at constant high weight.

 

Regards,

 

Your Fiat Ducato Owner Handbok will specify an inflation pressure of 5.5bar for your motorhome’s front and rear 225/75 R16 CP ‘camping tyres’ and - if the Laika handbook includes a tyre-pressure recommendation - I’d expect it to repeat the Fiat advice.

 

As I said above, Michelin will just echo the ETRTO’s stipulation that their CP-marked tyres fitted to a motorhome’s rear-axle should be inflated to 5.5bar, but my experience has been that Michelin will normally provide a pressure-to-axle-weight datum for their CP-marked tyres when these are fitted to a motorhome’s front-axle.

 

As the pressure-to-axle-weight ‘graph’ for a Michelin 225/75 R16 CP 116 ‘camping tyre’ will closely resemble the graph for a Continental 225/75 R16 CP 116 ‘camping tyre’, if a motorhome owner has FAW and RAW data (either from the motorhome’s VIN-plate(s) or via a weighbridge) usable pressure-to-weight values can be obtained from Continental’s Technical Databook that’s available on-line (2017-2018 version here)

 

https://tinyurl.com/y2d2kdwv

 

and the attached file shows the values for a Continental 225/75 R16 CP 116 tyre.

 

Obviously taking this DIY approach to obtaining tyre inflation-pressure data won’t be the same as asking the tyre manufacturer for information but, if a motorhome owner decides to overlook the advice in the vehicle’s handbook(s), it may be the best way forwards.

 

(Interesting that you mention your military background, as I remember - long ago on the old MMM forum when tyre pressures were being discussed - someone saying something like “I drove tanks in the army and I won’t alter the tyre pressures shown in my motorhome's handbook unless I get a direct order from the tyre manufacturer that it’s OK to do so”.)

[Laurence]

Derek Uzzell - 2019-04-21 8:28 AM

 

Laurence - 2019-04-20 6:45 PM

 

Derek Uzzell - 2019-04-20 8:51 AM

 

So, whatever you tell Michelin about your Burstner’s rear-axle weight-wise, Michelin will only provide a 5.5bar inflation figure..

 

I didn't even get that from Michelin. My previous MH had Continental tyres and the firm could not have been more helpful I gave them FAW, RAW and AUW (you see my military background there, all I need is a black patch and a space for a Chalk number on the front) and they sent me a wealth of useful information including the exact tyre pressures I should use.

 

The Laika came with Michelin Agilis 225/75 R16 CP 116Q, so after visiting a weighbridge I went through the same exercise with Michelin and I got standard response No 8 after a bit of a wait - consult the Fiat handbook; consult Laika; what does your mother say? All absolutely useless and unhelpful - a corporate exercise in sloping shoulders.

 

So I play it safe, I run both axles at 5.5 bar and so far that seems to have worked. As for the ride, well, I don't expect it to be that comfortable - it's a van chassis running at constant high weight.

 

Regards,

 

Your Fiat Ducato Owner Handbok will specify an inflation pressure of 5.5bar for your motorhome’s front and rear 225/75 R16 CP ‘camping tyres’ and - if the Laika handbook includes a tyre-pressure recommendation - I’d expect it to repeat the Fiat advice.

 

As I said above, Michelin will just echo the ETRTO’s stipulation that their CP-marked tyres fitted to a motorhome’s rear-axle should be inflated to 5.5bar, but my experience has been that Michelin will normally provide a pressure-to-axle-weight datum for their CP-marked tyres when these are fitted to a motorhome’s front-axle.

 

As the pressure-to-axle-weight ‘graph’ for a Michelin 225/75 R16 CP 116 ‘camping tyre’ will closely resemble the graph for a Continental 225/75 R16 CP 116 ‘camping tyre’, if a motorhome owner has FAW and RAW data (either from the motorhome’s VIN-plate(s) or via a weighbridge) usable pressure-to-weight values can be obtained from Continental’s Technical Databook

 

As I said above, the return advice from Michelin was non existent, and Laika only refer you to Fiat and your tyre manufacturer. The Laika handbook, for such a good motorhome, leaves a lot to be desired amd tries to cover too many models in one volume.

 

The Continental data you attached was sent to me when i was corresponding with them over my previous van, and in any case, their databook is available online. I have looked at all the weight/pressure ratios they give and pondered over changing my pressures in line with Continental data. However, you cannot guarantee that the design , construction and composition of the tyre is the same, and that the operational properties of the tyre are the same under all conditions as the Continental. Then there are insurance issues to consider in the event of an accident.

 

So, whilst I have considered the Continental data, I think it would be wrong to assume it can easily transfer or be applied to other makes of tyres. You might choose to do this, and maybe I am just more cautious, but for all their faults in communicating, I feel that Michelin must have good reasons to state 5.5 bar.

 

Regards,

[Derek Uzzell]

In the past Michelin (UK) published a hardcopy booklet equivalent to Continental’s softcopy technical data file. I had the 2004 booklet and this included inflation-pressure data for “XC Camping” tyres across a range of axle weights. The entries for the XC Camping pattern had a footnote recommending that for Continental European vehicles the rear-tyre pressure should be 5.5bar.

 

(I’ve several times explained on this forum the historical background that has led to why it’s now advised that CP-marked tyres be inflated to 5.0bar(F) and 5.5bar® when fitted to 15” wheels or 5.5bar (F & R) when fitted to 16” wheels and I’m not going to repeat myself.)

 

I don’t know if Michelin (UK) still produces the hardcopy handbook and, as far as I’m aware, there are no Michelin on-line files containing axle-weight-based pressure recommendations for “Agilis Camping” tyres.

 

Only 3 manufacturers (Continental, Michelin, Pirelli) currently offer CP-marked tyres. The contract for oriiginal equipment (OE) tyres for Fiat chassis destined for motorhome conversion has alternated between Continental and Michelin and, to the best of my knowledge, Fiat has never fitted Pirelli CP-marked tyres as OE.

 

If a Fiat Ducato-based motorhome has OE Continental or Michelin CP-marked tyres, the inflation-pressure advised in the Ducato Owner Handbook will remain the same - and the size, weight or number of axles that the ‘recreational vehicle’ has will also not influence that advice.

 

I’ve never had difficulty obtaining front-axle pressure-to-weight advice from Michilin for “Agilis Camping” tyres and, when I’ve done so, there was little difference between the Michelin advice and what was on Continental’s on-line chart for an equivalent “VancoCamper” tyre. So - if I were contemplating altering the pressures advised in the Ducato handbook for ‘camping tyres’ and those tyres were Michelins - I’d be comfortable using the Continental data for the rear tyres.

 

As you’ve been unable to get from Michelin the type of information available from Continental and you are reluctant to apply the Continental data to your Michelin tyres, there seems no alternative but to stick with the 5.5bar (F & R) recommendation in the Fiat handbook.

[Laurence]

Absolutely. That is what I concluded some time ago.

 

My post yesterday was not about what pressures I should run my tyres at, it was a comment on Michelin. You have obviously been lucky with them in the past, but my experience was not good.

 

Derek, I bow to your experience, but I think it is wrong to suggest - as you have done twice - that Continental data should be used to adjust Michelin tyres. You may choose to do this, but aside from insurance issues, there may be construction and design differences, and you cannot guarantee that under hot/cold/wet/dry/bumpy/ high speed/low speed/severe braking/cornering etc conditions that the tyre will act the same. Sorry, we differ here.

 

Regards,