# Tyre pressures again



## teal (Feb 23, 2009)

Had our Cheyenne weighed this week and it came out front axle 1500 kg and rear 1600kg that was with my Wife inside but not me (80kg) so with few more things inside total weight came to 3250 kg.We went for a 70 mile run today which was our first in this and at slow speeds of around 30 mph and when turning there is what i call shimmering /wobble but nothing felt on the steering wheel, just the unit was doing it , it does not last long because of moving faster, any idea's the tyre pressure is 5 bar as it say's on the cab doors.


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## MikeCo (Jan 26, 2008)

It's a wonder you can keep it on the road, most vehicles will have a similar weight on the front and I have tyres set at 55lbs which is around 3.8 Bar.
This is according to Michelin.


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## teal (Feb 23, 2009)

Hi MikeCo, so why does my cab doors say 5 bar front and back? but will look into what you say, thanks.


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## MikeCo (Jan 26, 2008)

teal said:


> Hi MikeCo, so why does my cab doors say 5 bar front and back? but will look into what you say, thanks.


I don't know the techical reason why or in fact any other reason but I follow the guide lines offered by the tyre manufacturer who have given me the pressures based upon the axle loads I gave them after visiting the weighbridge. This was with the van fully laded including enough Weetabix to last 6 weeks.


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## pete4x4 (Dec 20, 2006)

Also check what the max tyre pressure is. my tyres are 5 bar which is the same as the recommended pressure inside the door. I run mine at 4.3 bar tyres stay cool and I'm no where near max allowed pressure. Don't always believe what's on the door as that is for a goods van with van tyres.


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## 106559 (Aug 19, 2007)

Mercedes recommended pressures "on the door" are one heck of a lot less. O.K. RWD but these 5 bar front and rear do seem extraordinarily high. :?


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## 113016 (Jun 5, 2008)

Just remember that under inflated tyres get hot and blow out easier.
Most motorhomes are running at around the maximum permitted gross weight


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## MikeCo (Jan 26, 2008)

Grath said:


> Just remember that under inflated tyres get hot and blow out easier.
> Most motorhomes are running at around the maximum permitted gross weight


This is why my van was fully laden when I weighed it so that I could give the correct loads to Michelin.

Front 1600kg and pressures at 55 lbs

Rear 2400kg and pressures at 70 lbs


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## 106559 (Aug 19, 2007)

Now that sounds a lot more sensible.


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## 113016 (Jun 5, 2008)

MikeCo said:


> Grath said:
> 
> 
> > Just remember that under inflated tyres get hot and blow out easier.
> ...


Is not 70lbs about 5 bar
from memory I think that 72 lbs is 5 bar


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## 106559 (Aug 19, 2007)

Sounds about right for an axle at 2,400, not 1,600 as quoted.


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## MikeCo (Jan 26, 2008)

[/quote]
Is not 70lbs about 5 bar
from memory I think that 72 lbs is 5 bar[/quote]

Thats correct but the original post mentioned 1600kg on the rear at 5 bar where I am 2400kg at just under 5 bar.


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## Waggy (Jan 15, 2006)

I phoned Pirelli. They refused to give any guidance on pressures for their tyres. It is not their practice to do so 8O 

The label on the door pillar states 60psi front and 65psi rear. The weights are 1500/1850. Pirelli Chrono 225/70 R 15/ 

Thoughts anyone?


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## MikeCo (Jan 26, 2008)

Waggy said:


> I phoned Pirelli. They refused to give any guidance on pressures for their tyres. It is not their practice to do so 8O
> 
> The label on the door pillar states 60psi front and 65psi rear. The weights are 1500/1850. Pirelli Chrono 225/70 R 15/
> 
> Thoughts anyone?


My first thought is that I cannot understand why Pirelli will not offer advise and my second one is to knock 5 off each one.


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## rupert1 (Feb 13, 2009)

teal said:


> Had our Cheyenne weighed this week and it came out front axle 1500 kg and rear 1600kg that was with my Wife inside but not me (80kg) so with few more things inside total weight came to 3250 kg.We went for a 70 mile run today which was our first in this and at slow speeds of around 30 mph and when turning there is what i call shimmering /wobble but nothing felt on the steering wheel, just the unit was doing it , it does not last long because of moving faster, any idea's the tyre pressure is 5 bar as it say's on the cab doors.


You can ignore the plate on van door it is for the base vehicle. You must get the van weighed, fully loaded, then email the tyre supplier with all details, tyre sizes axle weights, and they will send you their recommended tyre pressures.


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## Waggy (Jan 15, 2006)

rupert1 said:


> teal said:
> 
> 
> > Had our Cheyenne weighed this week and it came out front axle 1500 kg and rear 1600kg that was with my Wife inside but not me (80kg) so with few more things inside total weight came to 3250 kg.We went for a 70 mile run today which was our first in this and at slow speeds of around 30 mph and when turning there is what i call shimmering /wobble but nothing felt on the steering wheel, just the unit was doing it , it does not last long because of moving faster, any idea's the tyre pressure is 5 bar as it say's on the cab doors.
> ...


Pirelli won't :evil:


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## ingram (May 12, 2005)

All this 'getting your 'van weighed' is ok, but my 'van does not always travel in the same loaded condition. It will depend on how long I am away for, if I take the generator with me or not, and probably several other factors. I also use it in an 'unloaded' condition for a day out. So, when I contacted Michelin I asked them for a recommendation for the pressures assuming maximum permissible axle loads and I used that as a guide. Their suggested pressures were far below those on the door post.

I don't disagree about weighing your motorhome to ensure that it is not overweight but I really don't think it necessary to stablish tyre pressures.

I don't alter my car tyre pressures according to how many people I am carrying....................

There was a website someone pointed to which gives recommendations for pressures according to tyre size / axle weights but forget where it is. Something to do with 'Motorhome Tyres', anyone else know?

Harvey


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## nedsez (May 1, 2005)

Hi all
Motorhome tyre safety info can be downloaded from here www.tyresafe.org/tyre-safety/
I think this will help, with facts rather than opinion.


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## ingram (May 12, 2005)

nedsez said:


> Hi all
> Motorhome tyre safety info can be downloaded from here www.tyresafe.org/tyre-safety/
> I think this will help, with facts rather than opinion.


Thanks nedsez that's the site I was mentioning.......... and now I have found I'd already downloaded the PDF, just forgot where I put it.

Harvey


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## teal (Feb 23, 2009)

So it looks like i will have to reduce mine to front 4.0 bar and rear 4.16 bar or 58-60 psi. Tomorrow we are off to Pickering so hoping for softer ride , thanks for your replies.
Robert


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## teal (Feb 23, 2009)

*Tyr pressures*

Well have now done our first 1000 mile trip up North via Pickering and whilst the tyres were at 5Bar i had also left a message to Michelin to contact me with what they should reccomend for our Cheyenne 634L. What we were experiencing was a wobble at 30/40 mph which then dissapered afterwards but as you know the 30/40 mph is what we are often at ie roundabouts etc , so we called into a tyre fitting place and had all four wheels checked and balanced. For the first hour or so we found the difference but later the wobble came back and as we were on our way back i left it until home. The firm up North said our wheels were out of balance quite a bit . In the South the firm said the front wheels were out but have not had a decent run to find out whether its cured. Michelin replied that our front should be 65 lb and rear 80 lbs. Which brings me to another subject .


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## normasand1 (Oct 4, 2006)

I contacted michelin early this year and was told VOSA have been involved, tyre pressures should be as recommended by manufacturer

Alan


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## loughrigg (Nov 10, 2008)

normasand1 said:


> I contacted michelin early this year and was told VOSA have been involved, tyre pressures should be as recommended by manufacturer
> 
> Alan


Is that the manufacturer of the tyre, the base vehicle or the MH?

Mike


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## normasand1 (Oct 4, 2006)

Base vehicle as on ns door pillar

Alan


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## teal (Feb 23, 2009)

*Tyre pressures*

As i said that it was Michelin camping tyre they gave me the pressure for that ,not the base vehicle which has ordinary tyres.


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## Jean-Luc (Jul 21, 2005)

How can any organisation insist on the singular pressures noted on the door pillar when at the time of attachment there is no information available as to the loading conditions and type of use to which the tyres will be subjected to when the vehicle eventually gets on the road as a converted unit.
On my Subaru THREE different sets of pressures are suggested depending on load and type of use.
Surely, only when actual axle loads and conditions of use have been defined can pressures be recommended, and then only by the company who manufactured the tyre in the first instance.

Colin


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## loughrigg (Nov 10, 2008)

normasand1 said:


> Base vehicle as on ns door pillar
> 
> Alan


According to my base vehicle manual, the door pillar pressures are based on the vehicle being fitted with Michelin tyres (I think it specified Agilis, but without digging out the the manual, I couldn't swear to that). My MH is currently fittted with a different model of tyre (Vredestein - which are of the correct grade and weight capacity) but which have a maximum pressure well below that of an Agilis or similar Michelin.

If I tried to inflate my current tyres to the door pillar pressure, the vehicle would be undriveable and there would probably be a very loud bang before too long (either from the tyre exploding or me hitting something).

Mike


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