jagmanx
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Tyre Pressures
- Thread starter Iain55
- Start date
Chris crofter
Free Member
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- 4
Motorhome pressures are often much higher than you expect. Do not inflate lower than the door sticker says! If tyres have been replaced and quote a max pressure lower then the van stickers say, you need to upgrade the tyres to proper van tyres rather than car tyres. Do not travel with over your plated max weight at any time! We were pulled and weighed by the police in Switzerland last year and only just made weight via a degree of small excess they allow! Penalties ares high!
Chris
snapster
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When we had our Autosleeper a few years ago, I went by the pressures on the door pillar and the handbook. I think they were 5 bar front and 5.5 bar rear.
We also had tyre pressure monitors.
After lots of discussions on Forums about pressures and people not being happy with the high pressures stated, I lowered mine and noticed immediately the tyres ran hotter ( tpms showed pressure and temps) so I went back to the recommended pressures.
Our new van runs at the recommended ( door pillar) pressures now, they were set at this from the dealer.
We also had tyre pressure monitors.
After lots of discussions on Forums about pressures and people not being happy with the high pressures stated, I lowered mine and noticed immediately the tyres ran hotter ( tpms showed pressure and temps) so I went back to the recommended pressures.
Our new van runs at the recommended ( door pillar) pressures now, they were set at this from the dealer.
Deleted member 3511
Guest
Deleted member 3511
Guest
Hi. This site has a cackuufor motorhome. Just enter your axle weights and tyre size and it will calculate the correct pressure I set mine on this and my tyre pressure and temperature monitor shows tyres not overheating or building pressure
https://www.tyresafe.org/check-your-pressures/motorhomes/
andyjanet
Full Member
- Messages
- 1,202
Just a thought but does anyone else find it shocking that Iain55 waited six months to check his tyre pressures, he says he’s new to motorhoming but his avatar picture doesn’t look as though he’s only just passed his test.
It’s not something I do daily but once every three weeks and always before a longish journey, tin hat strapped on running for the hills now?
It’s not something I do daily but once every three weeks and always before a longish journey, tin hat strapped on running for the hills now?
jadatis
Guest
The 5,5 bar behind is often realy needed to cover overloading on rear axle , wich is forbidden but happens verry often.
Then mostly the motorhome then is delivered with CP tires ( Camping Pneu ) , and most of them are 8PR/D-load tyres wich are allowed to carry the maximum load AT 65 or 69 psi. Michelin once answered me on my question by mail, that the 5,5bar 80psi is to cover "peakloads" , wich I translate as the always existing overloading of axles and tires for Motorhomes.
A normal C( omercial)-tyre was in earlyer days also allowed higher pressure then behind AT, but nowadays not anymore.
So only when the tyremaker puts it on the tyre , you are allowed now.
The Continental-Group often puts 2 pressures on sidewall .
1. behind the service descriptions the Pressure behind AT but without AT in front of it ( fi 195/70R16 109/107R 69 psi.
2. further behind the maxload information "maximum inflation pressure "of 10 psi higher ( in example then 79 psi) .
The first is the pressure at wich the maximum load can be carried upto 160km/99m/h without overheating any part of tyre.
The second is simply the maximum cold pressure the tyremaker allows to use.
The tyremaker does not support higher then maximum load at higher pressure then behind AT, but secretly they do that higher pressure for it.
They yust cant say it officially.
Front thoug can mostly do with lower pressure then the 4.5 bar, because MPAW is lower front and not totally used for motorhomes.
Sometimes even 3 bar/44psi or 3.5bar/51 psi is enaugh with comfortable savety margin even. This then gives better gripp and comfort.
But only do this after weighing the motorhome fully loaded as you go on trip ( so all persons and lugage, water , battery's, animal) .
then at least weigh per axle, better per axle-end.
Then give the data to me , and I trow it in my made extra save motorhome tyrepressure-calculator.
Greatings from a "Pigheaded Dutch sefdeclared tyrepressure-specialist".
Peter
Then mostly the motorhome then is delivered with CP tires ( Camping Pneu ) , and most of them are 8PR/D-load tyres wich are allowed to carry the maximum load AT 65 or 69 psi. Michelin once answered me on my question by mail, that the 5,5bar 80psi is to cover "peakloads" , wich I translate as the always existing overloading of axles and tires for Motorhomes.
A normal C( omercial)-tyre was in earlyer days also allowed higher pressure then behind AT, but nowadays not anymore.
So only when the tyremaker puts it on the tyre , you are allowed now.
The Continental-Group often puts 2 pressures on sidewall .
1. behind the service descriptions the Pressure behind AT but without AT in front of it ( fi 195/70R16 109/107R 69 psi.
2. further behind the maxload information "maximum inflation pressure "of 10 psi higher ( in example then 79 psi) .
The first is the pressure at wich the maximum load can be carried upto 160km/99m/h without overheating any part of tyre.
The second is simply the maximum cold pressure the tyremaker allows to use.
The tyremaker does not support higher then maximum load at higher pressure then behind AT, but secretly they do that higher pressure for it.
They yust cant say it officially.
Front thoug can mostly do with lower pressure then the 4.5 bar, because MPAW is lower front and not totally used for motorhomes.
Sometimes even 3 bar/44psi or 3.5bar/51 psi is enaugh with comfortable savety margin even. This then gives better gripp and comfort.
But only do this after weighing the motorhome fully loaded as you go on trip ( so all persons and lugage, water , battery's, animal) .
then at least weigh per axle, better per axle-end.
Then give the data to me , and I trow it in my made extra save motorhome tyrepressure-calculator.
Greatings from a "Pigheaded Dutch sefdeclared tyrepressure-specialist".
Peter
jadatis
Guest
Reply to above.
In this list you see that the referencepressure is that 4.75bar and psi calculated from in the row beneath it.
I checked it to be calculated with the official European formula, for who likes to know C=D* ( A/B) ^0,8 , that is used in Europe for every kind of tyre.
in wich .
A= the actuall pressure( pressure given in the above row in list)
B= The reference-pressure ( here 4.75bar/69psi)
C= The loadcapacity belonging to A.
D= The maximum load of tyre (here 2500kg/2tyres=1250kg)
^0,8 is the thing most wont understand, means to the power like ^2 is squaire and ^0,5 = root. on sciencetific calculators is a button X^y
But the rear axle list, that goes as high as 5,5 bar , they solved the" not saying it is for overloading problem", by using that maximum cold pressure , and calculated from that ,wich Continental-Group also gives on CP tyres.
Other brands in The Continental Group that also give the 2 pressures.
Semperit
Vanco
Viking
Uniroyal
If I would calculate with my made extra safe spreadsheet , I fill in the 4.75bar and add, when only MPAW given, 18 % of that.
Then if that once that rear axleweight is realy exact MPAW and equally devided , then the real weight is 85% of the weight the pressure is calculated for.
I determined by reactions, that then comfort and gripp is still acceptable, and gives as much possible reserve for overloading.
Then I calculate it with a formula that comes to even higher pressure then the pretty safe European official.
The outcome for rear axle might then come to the same as the list for rear axle single.
Only me as individual says what it is done for, and that is the expected overloading.
So if you use this list, for front add 10% to the weighed load and search back in that list at the row for single load front.
For rear do the same but the weighed load + 10% is probably higher then then what is given for 4.75 bar.
Or you let me calculate it.
Give from motorhome
Best weighed loads fully loaded as you go on trip, per axle , but best per axle-end.
But when you dont have that give MPAW's front and rear.
Give maximum speed you use and wont go over for even a minute ( so be hounest).
And the configuration like rear Single or Dual load axle or Tandem-axle.
From tyres:
1 maximum load or loadindex ( single and Dual if needed).
2 reference-pressure ( tricky part but in the list the 4.75 psi and not the maxcold of 5,5 bar/80psi for CP)
3. speedcode, a letter mostly Q or R for Motorhome tyres. Can do without because of always 160kmph/99mph reference speed)
You can also download the spreadsheet from this submap on my public map of One-drive.
Motorhome map but from this you can navigate complete public map
The multi-language part I made together with an Englishman , who had better Excell-skils then me.
In this list you see that the referencepressure is that 4.75bar and psi calculated from in the row beneath it.
I checked it to be calculated with the official European formula, for who likes to know C=D* ( A/B) ^0,8 , that is used in Europe for every kind of tyre.
in wich .
A= the actuall pressure( pressure given in the above row in list)
B= The reference-pressure ( here 4.75bar/69psi)
C= The loadcapacity belonging to A.
D= The maximum load of tyre (here 2500kg/2tyres=1250kg)
^0,8 is the thing most wont understand, means to the power like ^2 is squaire and ^0,5 = root. on sciencetific calculators is a button X^y
But the rear axle list, that goes as high as 5,5 bar , they solved the" not saying it is for overloading problem", by using that maximum cold pressure , and calculated from that ,wich Continental-Group also gives on CP tyres.
Other brands in The Continental Group that also give the 2 pressures.
Semperit
Vanco
Viking
Uniroyal
If I would calculate with my made extra safe spreadsheet , I fill in the 4.75bar and add, when only MPAW given, 18 % of that.
Then if that once that rear axleweight is realy exact MPAW and equally devided , then the real weight is 85% of the weight the pressure is calculated for.
I determined by reactions, that then comfort and gripp is still acceptable, and gives as much possible reserve for overloading.
Then I calculate it with a formula that comes to even higher pressure then the pretty safe European official.
The outcome for rear axle might then come to the same as the list for rear axle single.
Only me as individual says what it is done for, and that is the expected overloading.
So if you use this list, for front add 10% to the weighed load and search back in that list at the row for single load front.
For rear do the same but the weighed load + 10% is probably higher then then what is given for 4.75 bar.
Or you let me calculate it.
Give from motorhome
Best weighed loads fully loaded as you go on trip, per axle , but best per axle-end.
But when you dont have that give MPAW's front and rear.
Give maximum speed you use and wont go over for even a minute ( so be hounest).
And the configuration like rear Single or Dual load axle or Tandem-axle.
From tyres:
1 maximum load or loadindex ( single and Dual if needed).
2 reference-pressure ( tricky part but in the list the 4.75 psi and not the maxcold of 5,5 bar/80psi for CP)
3. speedcode, a letter mostly Q or R for Motorhome tyres. Can do without because of always 160kmph/99mph reference speed)
You can also download the spreadsheet from this submap on my public map of One-drive.
Motorhome map but from this you can navigate complete public map
The multi-language part I made together with an Englishman , who had better Excell-skils then me.