# Tyre Pressure



## buttsvanman (Nov 18, 2011)

Can anyone help with the tyre pressure on peugeot starfire van please:dance:


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## Tony Lee (Nov 18, 2011)

Given that most motorhomes are either overloaded or close to it, the best and safest way is to get to a weighbridge and weigh each axle individually so you can work out the correct tyre pressure from the tyre manufacturer's data sheets.

Last person to ask is any employee of a tyre retailer.


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## Techno100 (Nov 18, 2011)

I think Michelin are now recommending maximum pressure in the rear and adjust for comfort in the front.
In a period exceeding a year I have found this works for me and I have 55 front 80 rear in my Michelin Agilis Camping 15"
I would say I could well let some more out of the front if needed.
Autocruise Starspirit.

Andy


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## Bernard Jones (Nov 18, 2011)

There was some survey recently where many motorhomes were found to be overloaded on the back axle, and ever since then Michelin have always advised the maximum pressure in the rear tyres of 80psi irrespective of the vehicle or load. (Yes really! - ask anyone who has contacted them)
The best way is to weigh the vehicle on a weighbridge to work out the weight on each axle, then look the pressures up from this chart; (link) http://www.tyresafe.org/images/tyre-safety-guide/motorhome-leaflet.pdf

Incidentally this site gives a lot of other useful info on tyres (link) British Tyre Manufacturers Association Tyre Guidance Statements


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## Tony Lee (Nov 18, 2011)

> Michelin have always advised the maximum pressure in the rear tyres of 80psi irrespective of the vehicle or load. (Yes really! - ask anyone who has contacted them)



Could we have an authoritative source for this advice please. Perhaps a pointer to the Michelin web site or an official publication. Since they have "always" given this advice, it should be easy to verify.


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## Techno100 (Nov 19, 2011)

To my knowledge this appears to be a recent stance from Michelin as I've read of folk last year being given specific front and rear pressures.
I prefer the latest advice as I doubt that there are motorhomes in abundance that are not up to or over the limit on the rear.
The front is more important as it affects comfort and handling, over inflation loses traction and shakes out your fillings.
Mine handles and feels much better at 55psi than anything higher so far and may even be better with a bit more out


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## just jane (Nov 19, 2011)

Techno100 said:


> To my knowledge this appears to be a recent stance from Michelin as I've read of folk last year being given specific front and rear pressures.
> I prefer the latest advice as I doubt that there are motorhomes in abundance that are not up to or over the limit on the rear.
> The front is more important as it affects comfort and handling, over inflation loses traction and shakes out your fillings.
> Mine handles and feels much better at 55psi than anything higher so far and may even be better with a bit more out



I was advised 55 front and 80 back by Michelin after a trip over the weighbridge about 18 months ago and I was told that motorhomes are easy to overload so they advise maximum pressure in the rear in most cases, even though I was nowhere near overloaded.


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## Techno100 (Nov 19, 2011)

Looking back at my history with our van.
We collected it from the previous owner who had filled all 4 tyres to 79psi as per the door pillar label. It drove like a complete pig and had no traction and was blown about by every passing vehicle.
I reduced the pressures to 60 front 65 rear which made a huge improvement. At this time the vehicle had nothing but a towbar as extra weight.
I have since added a twin bike rack 2 bikes a fixed ladder 4 solar panels a crank up satellite an extra battery etc so the max pressure of 80 rear makes complete sense.
At the same time I have gradually lowered the fronts to 55 which is more than adequate when full of diesel and a full belly of water, so much so that I'd go as low as 50 if doing a lot of rough roads or snow.


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## Bernard Jones (Nov 19, 2011)

Tony Lee said:


> Since they have "always" given this advice.



Thats not quite what I said is it?


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## Techno100 (Nov 19, 2011)

Bernard Jones said:


> Thats not quite what I said is it?


No Bernard it was preceded by EVER SINCE THEN


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## Bernard Jones (Nov 19, 2011)

Tyre pressures are a compromise.  The harder the wheels, the less rolling resistance, the lower the fuel consumption.  But if you take that to its logical conclusion we would be driving on solid steel wheels (with no suspension) which would quickly shake both us and our vehicles to bits.
You have to compromise, even at the expense of fuel consumption, because you have to have some cushioning.


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## Bernard Jones (Nov 19, 2011)

Techno100 said:


> No Bernard it was preceded by EVER SINCE THEN



Thank you Techno.
As you may know a tactic some people use is to mis quote somebody, then use that mis quote to rubbish them.  So its always a good idea to find out for yourself what they said.


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## Tony Lee (Nov 19, 2011)

Bernard, an even more irritating ploy is is to beat around the bush instead of giving authoritative sources for your claims.



 Michelin may have someone (so far unspecified) giving out some tyre-pressure-for-morons advice, but until I see an official source specifying that that is THE rule to be blindly followed from now on, I will be using weight/pressure tables to work out the basic inflation requirements and then modifying them according to my driving habits and road conditions. THAT is what Michelin and every other tyre manufacturer advises.

I suggest anyone with any consideration for their tyres and their safety, would be very smart to do likewise.


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## just jane (Nov 19, 2011)

Tony Lee said:


> Bernard, an even more irritating ploy is is to beat around the bush instead of giving authoritative sources for your claims.
> 
> 
> 
> ...



But Michelin do provide a service to customers where they can email or phone with weighbridge info and be given specific psi for their vehicle, Im sure they work off tables like you suggest but as I have posted in the other tyre thread they told my tyre fitter that they recommend 80psi because it is so easy to overload the back axle of a motorhome.


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## Bernard Jones (Nov 19, 2011)

just jane said:


> But Michelin do provide a service to customers where they can email or phone with weighbridge info and be given specific psi for their vehicle, Im sure they work off tables like you suggest but as I have posted in the other tyre thread they told my tyre fitter that they recommend 80psi because it is so easy to overload the back axle of a motorhome.



Thats what I, and others I know, have found too.
After emailing them with the weights, Michelin replied telling me 80psi for the rear of my X2/50 maxi van too.  Wheras the tyre pressure chart I posted in post 4 suggests around 44 psi all round, so thats what I have been running at for the last 18 months.  Its a noticeably better ride, with no sign of the tyres overheating.  I have done 18,600 miles,  the tyres front are about half worn, and the rear tyres about a third worn. (Front wheel drive) Regarding fuel consumption, my records indicate fuel consumption is slightly lower than when I was running with the tyres at higher pressure, but I think that is a result of the engine bedding in, and nothing to do with tyre pressures. 


This is the reply I received from Michelin (copied and pasted)

_Dear Sir/Madam 

Thank you for your recent e-mail.

We suggest that individual axle weights from weigh scale readings are used, in order to calculate pressure recommendations for each quoted load condition. These would be preferred, due to readings being taken in the actual vehicle 'running' condition - that is to say, with all water/fuel/baggage & passengers etc. onboard - and may result in better comfort if the vehicle is running way below maximum capacity.

The results of roadside surveys indicate that some motor homes have been found to be over laden, especially the rear axle, with potential for subsequent tyre related problems.

The overall tyre industry, therefore, tries to build-in a safety factor by fitting strong tyres, inflated to high pressure, in order to remove the potential for consequences of overloading &/or under-inflating the tyres.

The drawback of this safety factor, at the corresponding high pressure, may be an extremely hard ride. The contents of the motor home may rattle, but the tyres will cope nicely.

One 'overall' weight is of no use in calculating tyre inflation pressure levels, since the vehicle may appear to be within the maximum permitted, but in reality may have the rear axle severely over laden & the front axle very lightly laden.

As a guideline from the axle weights that you have supplied on tyre size 225/75 R16C if being the Michelin Agilis Camping the pressures for those weights should be as follows:-

Front axle load of 1540kg the pressure should be – 50psi (pounds per square inch)
Rear axle load of 1480kg the pressure should be – 80psi (pounds per square inch)

You would be advised to follow the manufacturers recommended pressures, indicated on the fuel cap / door-pillar / vehicle handbook in relation to the tyre size fitted – specifications can change without our knowledge. 


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.

Yours sincerely
Michelin Tyre Public Limited Company_


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