2009 Nuevo Classic - Tyre Pressures

The 69 max tp is for the american market   not UK .
For  clarification  of tyre pressure  law visit  RoSPA  web site .

Caraman wrote:Well spotted Knick-Knack - thanks - I hadn't seen that.  5.5 BAR is 79.7 psi which is 0.2 psi above the figure shown on the passenger door post for the rear tyres.  There is another AS label on the passenger door post which seems to show the maxm axle loadings which appear to be 1850kg front and 2000kg rear.  I wonder if the tyre pressure figures on the door post relate to these maxm axle loadings.  I am still trying to decipher the Continental table.

what are your axle weights and tyre size?

bolero boy wrote:what are your axle weights and tyre size?

Thanks - no idea what my actual axle weights are as I haven't had them measured and didn't think I needed to as I know the load I carry is always well below the maximum permissible for my 2 berth/seat Nuevo.  I've found the tyres on the Continental table - they are VancoCamper 215/70 R15 CP 109R.  I can now see the axle weight 'v' tyre pressure figures which indicate that the pressures shown on the passenger doorframe are for the maximum permissible axle weights of 1850 kg front 2000 kg rear.  These figures are probably no different to the bigger and heavier AS Broadway whose maximum permissible laden mass of 3500 kg is the same as the Nuevo.

glyne lock wrote:Caraman
1 so how do you set the pressures ? by the load
2 what is the plate for on the door ?
3 can the police find fault with you lowering  the pressures as long as they are at a safe pressure .

Q1 - not by load, by the figures on the plate on the door
Q2 - I thought it was to tell me the tyre pressures I must use.  It now appears they merely indicate the tyre pressures to use if either axle is at its maximum permitted load which mine are no where near although I haven't measured them.
Q3 - Not for me to say

glyne lock wrote:Caraman
you need to please watch the mmmy  ytube motor home tyre pressure as you are clearly out of your depth here as the old saying goes in the trade your never to old to learn

Please can you send me a link to mmmy ytube motor home tyre pressure and then I will decide if I am out of my depth.

I prefer to believe the manufacturer of my tyres recommendations as to suitable pressures.

Someone is being unnecessarily antagonistic.

Are you referring to YouTube?

I watched one YouTube video by mmm on Motorhome tyre pressures and all it showed was how to check pressures with a guage and how to use a compressor to inflate them. I suggest you put a link to the exact video you refer to.

I have just seen a Motorhome Monthly Magazine video which at the start briefly confirms what mikethebike, ploughlin, bolero boy and cymro have been saying which is that the actual axle weights measured on a weighbridge should be used to determine the tyre pressures in accordance with the tyre manufacturer's instructions.  This largely answers the orginator of this thread's question and should be informative for other members of the forum.  It's a shame that neither AS nor the C&MC give this type of advice.  If they do, I haven't seen it.

glyne lock wrote:the first thing he says is to visit a weighbridge to get the axle weight then refer to tyre manufacture settings for the pressure is that what you watched paul

The one I watched also pointed out the max pressure printed on the tyre which we've already established is for US market. I think this thread has said all that needs to be said.

Perhaps this link to Michelin's advice is the best to adhere to....

https://dgaddcospreprod.blob.core.windows.net/b2c-experience-preprod/attachments/cjqg866zh05be0opeu8meuubg-tc-safety-guide-uk.pdf

Paulmold wrote:Perhaps this link to Michelin's advice is the best to adhere to....

https://dgaddcospreprod.blob.core.windows.net/b2c-experience-preprod/attachments/cjqg866zh05be0opeu8meuubg-tc-safety-guide-uk.pdf

I have had a good look at this but I don't think it really helps.  It includes the following "Follow the vehicle manufacturer’s tyre inflation pressure recommendations."  "Ensure that the tyre inflation pressures are readjusted to comply with the vehicle manufacturer’s recommendations."  Well for my Nuveo that can only be the very high figures shown on the tyre pressure plate on the inside of the passenger door.  No other tyre pressures are given by the vehicle manufacturer or at least none that I can find.  It also includes specific advice for motorhomes - "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."  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”.  The important outcome of this ASOF thread and previous similar threads seems to be that the vehicle manufacturer's recommendations on the tyre pressure plate on the inside of the passenger door should be disregarded and instead the loaded axle weights should be measured on a weighbridge and these weights used with the tyre manufacturer's recommendations to determine the tyre pressure.  This is not mentioned in Michelin's advice.

I just adjusted my pressures till I found a compromise between stability and comfort that I was happy with.

Peter Brown wrote:I just adjusted my pressures till I found a compromise between stability and comfort that I was happy with.

Similar to myself. However 165 threads on here about tyres,so this comes up every year.
What members should do is check pressures and tyre condition on a regular basis.
nothing more to add from me.



Micky

Now I have a keyboard again, I should add to my previous post that I did not adjust pressures 'willy nilly'. I was aware that my Mercedes plate stated that for a Motorhome conversion the tyres should be inflated to the maximum of the range given on the plate and that the pressures recommended by Continental for the maximum loading of each axle were considerably less than those, so experimented in the area between those two sets of figures.

Peter Brown wrote:so experimented in the area between those two sets of figures.

Thanks Peter.  If I have understood you correctly, the difference for my Peugeot is that the plated pressure is a single figure of 5.0 Bar front and 5.5 Bar rear.  The only latitude given is +/- 0.05 Bar.  If MMM approach is adopted, which makes no reference to the manufacturer's plated pressure, the plated pressure is being ignored, or, a new one is being used by the owner which for the front tyres might be say 3.0 Bar to 5.0 Bar and the rear tyres say 5.0 Bar to 5.5 Bar.  I am taking advice on this from the design authority (AS) and the tyre manufacturer (Continental) as others who have a concern in this area should do.  If both say that running the motorhome at lower pressures than the plated figures is not posing a risk to the occupants and other road users, I am happy to drop my pressures probably to around 3.25 Bar front and 5.0 Bar rear to reflect the actual axle weights.  This will give a more compliant ride and probably improve front wheel traction on soft ground.

I agree with the exception that front wheel traction is impacted by weight distribution (by accelerating/braking) ground surface condition, throttle and (if fitted) clutch control. Tyre pressure adjustment in the range we are discussing will make no noticeable difference.

Peter Brown wrote:I agree with the exception that front wheel traction is impacted by weight distribution (by accelerating/braking) ground surface condition, throttle and (if fitted) clutch control.  Tyre pressure adjustment in the range we are discussing will make no noticeable difference.

You're probably right but I live in hope.  Dropping the pressure on my tubeless mountain bike makes a big difference to traction on slippery ground.

First estimation of weight and division over the axles, is dangerous, mostly in real more.
Second , you can add 10% to the axleloads, and llok those weights back, ans still have acceptable comfort and gripp, and this gives maximum reserve for things like, pressureloss in time, misreading of pressure, some extra load, etc. 

What are the max permissable axleloads, the motorhomes of these weights often are overloaded on rear axle, but front axle stays below MPAW. 

The tyres on Continental group give often 2 pressures, 1 right behind the service descriptions 109R  69psi , I think for your sise. 
This is called the referencepressure and is in your list( wich I dont see in your post) the highest pressure where the 1030 kg loadcapacity is given.

If this reference is written at 12 o clock, then on 6 o clock after the maxloadstory for CP 80 psi is written, and this is simply the maximum cold pressure the tyremaker allowes. 
This you can use to cover the forbidden overload on rear axle.

My dangerous estimation is that my calculation will come to 80psi/5,5bar rear and 59psi/4bar front. 

Greatings from a " pigheaded Dutch selfdeclared tyrepressure-specialist"