# Tyre pressure



## Fisherman (Aug 25, 2021)

Apologies for bringing up a subject discussed many times on here.
I have mitchelin agilis tyres which I run at 65psi.
My van is a 3.5T ducato a class.
But once warmed up after a few miles they rise to around 72psi.
Reading some posts on here I may be running a bit under pressure.
Any opinions on this.

Thanks in advance.


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## trevskoda (Aug 25, 2021)

I run my 6.3 ton bus at 65psi and tyres wear even, any harder and the edges wear and it is a hard ride on bumpy roads, but i have double wheel r axle, fronts fine at 65 to.


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## RichardHelen262 (Aug 25, 2021)

On our sprinter based motorhome rated 3850kg i run the rears at 65 and fronts at 55 psi


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## Scotia (Aug 25, 2021)

I run the front at 65 and rear at 67 on a 5 ton double axle. When I came back from getting 4 new rear tyres fitted last month I found the mh was wandering on checking the pressure they had only put in 45psi.


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## izwozral (Aug 25, 2021)

Was told by my mechanic and someone who had a tyre company, that one of the causes of tyres perishing is running them under inflated, as well as exposure to the sun.
Just to complicate matters, the tyre pressures should be adjusted according to load.

I've been running mine at 79psi as stipulated as I am always fully loaded.


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## Scotia (Aug 25, 2021)

izwozral said:


> Was told by my mechanic and someone who had a tyre company, that one of the causes of tyres perishing is running them under inflated, as well as exposure to the sun.
> Just to complicate matters, the tyre pressures should be adjusted according to load.
> 
> I've been running mine at 79psi as stipulated as I am always fully loaded.


Go on a diet then!


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## maingate (Aug 25, 2021)

Scotia said:


> I run the front at 65 and rear at 67 on a 5 ton double axle. When I came back from getting 4 new rear tyres fitted last month I found the mh was wandering on checking the pressure they had only put in 45psi.


The rears seem a bit high to me. I had the old 747 with 5 Ton MAM and I ran them at 50 psi but on mine most of the weight was on the front axle (I had to be careful with the front axle loading).

My current van is on the same Alko chassis as yours and I run at 50 psi. Anything more and the rattles get louder.  If your 2 rear axles are rated at 1500 Kg each and you are not overloaded then try dropping them a bit. You could also feed in your weight info on the Tyresafe website. They give figures properly for tag axle vans, anything with only 2 axles automatically give 80 psi for some reason.


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## trevskoda (Aug 25, 2021)

My ex library bus is light loaded by miles, hence at 65psi rather than the 80/85 rated on the sidewall.


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## colinm (Aug 25, 2021)

Fisherman said:


> Apologies for bringing up a subject discussed many times on here.
> I have mitchelin agilis tyres which I run at 65psi.
> My van is a 3.5T ducato a class.
> But once warmed up after a few miles they rise to around 72psi.
> ...


Anyway to get back to OP.
All tyre pressures rise when used as they heat up, so that in itself is not a problem. What you need to consider is the size and load index compared to the axle loads, anything else is just random figures which are meaningless.


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## Scotia (Aug 25, 2021)

maingate said:


> The rears seem a bit high to me. I had the old 747 with 5 Ton MAM and I ran them at 50 psi but on mine most of the weight was on the front axle (I had to be careful with the front axle loading).
> 
> My current van is on the same Alko chassis as yours and I run at 50 psi. Anything more and the rattles get louder.  If your 2 rear axles are rated at 1500 Kg each and you are not overloaded then try dropping them a bit. You could also feed in your weight info on the Tyresafe website. They give figures properly for tag axle vans, anything with only 2 axles automatically give 80 psi for some reason.


It us loud when hitting bumps, but looking at the tyre wear on the old tyres and it was even.


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## mark61 (Aug 25, 2021)

Yes, weigh bridge, axle weights, load index and do the calculations. Would be the best way. That doesn't mean knowing the temp increase is of no help though.

Those that go completely off piste with their choice of tyres have only two ways off working out a tyre pressure. The above and the temp increase after say 30 mins driving. You'll have to do a search because I can't remember exactly what it is,   anyway it's surprisingly accurate.

I'll stick my neck out and guess if your pressure is going up over 10% cold to hot, your under inflated. Mainly cause I like sticking my neck out


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## Fisherman (Aug 25, 2021)

mark61 said:


> I'll stick my neck out and guess if your pressure is going up over 10% cold to hot, your under inflated. Mainly cause I like sticking my neck out


Well being made from brass, your quite safe mark


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## wildebus (Aug 25, 2021)

mark61 said:


> Yes, weigh bridge, axle weights, load index and do the calculations. Would be the best way. That doesn't mean knowing the temp increase is of no help though.
> 
> Those that go completely off piste with their choice of tyres have only two ways off working out a tyre pressure. The above and the temp increase after say 30 mins driving. You'll have to do a search because I can't remember exactly what it is,   anyway it's surprisingly accurate.
> 
> *I'll stick my neck out and guess if your pressure is going up over 10% cold to hot, your under inflated*. Mainly cause I like sticking my neck out


It depends on the time of year for one thing. 
I have found after using aftermarket TPMS systems for over 15 years on various vehicles the starting pressures vary significantly when "cold" - as "cold" in the UK can be anywhere from below -0C to over 25C, but the end "hot" temp if there is not a fault is consistant as the tyres get to an operating temp in around 20 minutes.
That is my take on the changing temps.
As far as 65 PSI goes, sounds about right to me for a 3.5t van.


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## argoose (Aug 25, 2021)

Read a good article a while back and it mentioned the rule of 4&6.
Car tyres should rise 4psi cold to hot.
Van tyres should rise 6psi cold to hot.
Any more your under inflated.
Any less your over inflated.
Not gospel, but old mechanic thinking.
It struck a chord that tyres do increase, so why not quantify it. The values seem reasonable in my head, but also I feel the side walls after a run to check temp.


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## Fisherman (Aug 25, 2021)

argoose said:


> Read a good article a while back and it mentioned the rule of 4&6.
> Car tyres should rise 4psi cold to hot.
> Van tyres should rise 6psi cold to hot.
> Any more your under inflated.
> ...


Well that’s just about right, they normally rise from 65psi to 72-73psi.


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## barge1914 (Aug 25, 2021)

Same van as yours Bill, except a little heavier on the front axle with automatic and 140 engine.

 I spoke to Michelin for confirmation of pressures as Roller Team recommend 80psi for both front and rear. Michelin we’re unrelenting in affirming 80psi on rear on all motorhomes with these tyres ‘for stability’. They did however say for my normal loaded axle weights 1800kg front and 1600kg back I could go down to 65 on the front for a more comfortable ride, with an absolute minimum of 55psi. 

I had been running them like you at 65psi all round which gave a much more comfortable and adequately stable ride. At 80kg all round it was like driving on concrete wheels, bang bang rattle bang, and very poor traction soft ground.

I’ve since gone back up to 75kg on the back, staying at 65 on the front, but I’m not at all happy with the amount of noise that produces, or with having much harder tyres and what must be poorer grip on the lightly loaded and now more skittish rear. I had always understood it was better to have the better grip on the rears to avoid the back end ‘overtaking’ and skidding on wet roads when braking.

My previous van had also originally CP tyres, but Continental. That was heavy on the rear and light on the front. They were quite happy to recommend lower pressures more in keeping with the actual loading.

I can understand higher pressure on the more heavily loaded wheels to maintain tyre profile and avoid wear from too much tyre on the road. But still haven’t really had a satisfactory explanation of why it should be the converse on this van.


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## mark61 (Aug 25, 2021)

Fisherman said:


> Well that’s just about right, they normally rise from 65psi to 72-73psi.


Much the same as the 10% then.


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## Fisherman (Aug 25, 2021)

mark61 said:


> Much the same as the 10% then.


They only teach fractions up here


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## wildebus (Aug 25, 2021)

barge1914 said:


> Same van as yours Bill, except a little heavier on the front axle with automatic and 140 engine.
> 
> I spoke to Michelin for confirmation of pressures as Roller Team recommend 80psi for both front and rear. Michelin we’re unrelenting in affirming 80psi on rear on all motorhomes with these tyres ‘for stability’. They did however say for my normal loaded axle weights 1800kg front and 1600kg back I could go down to 65 on the front for a more comfortable ride, with an absolute minimum of 55psi.
> 
> ...


When you say "these tyres", which tyres are you referring to?
It is well known that michelin go on about 80PSI on the Aglis Camping Tyres, but what about the other Aglis tyres  (as far as I know, "Aglis" is their term for van tyres - be they camping or any other type.  I have Michelin 'Aglis' tyres on my Motorhome but they are not Camping ones)


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## trevskoda (Aug 25, 2021)

I put anything on if cheap, just bought 5 of ebay with over 9mm tread, got them this morning and they are like new, and at a fraction of what tyre shops wanted here, 3 are winter mud and snow.


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## mark61 (Aug 25, 2021)

Fisherman said:


> They only teach fractions up here


Anyway, joking aside, your tyres are pretty close to both the 4 & 6 Rule mentioned by argoose and the 10%.

Heres an article by Cooper tyres mentioning the 4 & 6 rule.

https://www.coopertires.com.au/media/118192/2017-Dec_Cooper-Tyre-Tips-guide_LR.pdf

Only thing, what’s a light truck/van/4x4.   2800KG, 3200KG, 3500KG, 5500KG? 

Can I make a new rule, the rule of 7 for 3500 KG, owzthat, your spot on.


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## molly 2 (Aug 26, 2021)

The op dose not state Agilis or Agilis camping ? Presume he means camping


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## trevskoda (Aug 26, 2021)

Whats the difference in camping tyres, do they come with a silly hat boots and a walking stick.


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## RoadTrek Boy (Aug 26, 2021)

trevskoda said:


> Whats the difference in camping tyres, do they come with a silly hat boots and a walking stick.


No, just a silly price...


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## mark61 (Aug 26, 2021)

trevskoda said:


> Whats the difference in camping tyres, do they come with a silly hat boots and a walking stick.


Nooooooo!, don't go there.


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## barge1914 (Aug 26, 2021)

wildebus said:


> When you say "these tyres", which tyres are you referring to?
> It is well known that michelin go on about 80PSI on the Aglis Camping Tyres, but what about the other Aglis tyres  (as far as I know, "Aglis" is their term for van tyres - be they camping or any other type.  I have Michelin 'Aglis' tyres on my Motorhome but they are not Camping ones)


Michelin Agilis CP tyres.


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## trevskoda (Aug 27, 2021)

Any tyre thats not flat at the bottom is a good one.


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## Big Chief (Aug 27, 2021)

Fisherman said:


> Apologies for bringing up a subject discussed many times on here.
> I have mitchelin agilis tyres which I run at 65psi.
> My van is a 3.5T ducato a class.
> But once warmed up after a few miles they rise to around 72psi.
> ...


If you want to know what tyre pressures to run then take a look at this website https://www.tyresafe.org/motorhome-tyre-pressure/ 
My vehicle is a 4.5 ton Autotrail Chieftain and the tyre pressures are 3.9  Bar (57psi) on the front axle which is rated at 1.8 tons, and 3.5  Bar (53psi) on the rear tag axles which are rated at 1.5 tons. A much better ride and best minimal tyre wear has been achieved since consulting "Tyre Safe"


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## barge1914 (Aug 27, 2021)

Big Chief said:


> If you want to know what tyre pressures to run then take a look at this website https://www.tyresafe.org/motorhome-tyre-pressure/
> My vehicle is a 4.5 ton Autotrail Chieftain and the tyre pressures are 3.9  Bar (57psi) on the front axle which is rated at 1.8 tons, and 3.5  Bar (53psi) on the rear tag axles which are rated at 1.5 tons. A much better ride and best minimal tyre wear has been achieved since consulting "Tyre Safe"


That tells me 53psi front and 80psi rear but for full plated loads. But actual rear is 1600, and for gross vehicle weight I can only put 1700kg on rears….so still unsure.


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## RV2MAX (Aug 27, 2021)

The 4&6 rule is well known in Australia  , as due to conditions people are generally very tyre conscious, they also wear out quicker .  I found it to be pretty sound rule, on several types of  vehicles .  It is important to  adjust at different axle loads tho .  Whereas Manufacturer pressures are usually for max load scenario .


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## wildebus (Aug 27, 2021)

Big Chief said:


> If you want to know what tyre pressures to run then take a look at this website https://www.tyresafe.org/motorhome-tyre-pressure/
> My vehicle is a 4.5 ton Autotrail Chieftain and the tyre pressures are 3.9  Bar (57psi) on the front axle which is rated at 1.8 tons, and 3.5  Bar (53psi) on the rear tag axles which are rated at 1.5 tons. A much better ride and best minimal tyre wear has been achieved since consulting "Tyre Safe"


Interesting Site. 
I have been running around 65PSI all round on my Michelin Aglis (non-Camping) shod 3850kg MH and thought I should up it a little since I did the weight uprate from 3500 to the new 3850  - but Tyresafe.org is saying I am actually spot on at the rear and a bit high at the front.


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## maingate (Aug 27, 2021)

barge1914 said:


> That tells me 53psi front and 80psi rear but for full plated loads. But actual rear is 1600, and for gross vehicle weight I can only put 1700kg on rears….so still unsure.


You have put your axle weights in correctly, now reverse the weights (ie front is rear) and see what the readings are. On a 2 axle motorhome 80 psi is *always* quoted for rear axles on tyresafe. That will give you the actual recommended pressure for both axles.


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## barge1914 (Aug 27, 2021)

maingate said:


> You have put your axle weights in correctly, now reverse the weights (ie front is rear) and see what the readings are. On a 2 axle motorhome 80 psi is *always* quoted for rear axles on tyresafe. That will give you the actual recommended pressure for both axles.


Do you know why Tyresafe always quote 80 for rear? Michelin do also, but Continental give pressures according to true axle weight.


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## barge1914 (Aug 27, 2021)

barge1914 said:


> Do you know why Tyresafe always quote 80 for rear? Michelin do also, but Continental give pressures according to true axle weight.


Just done what you say now says 61. I find tyresafes explanation unsatisfactory because surely the ‘special’ circumstances of motorhome loading are relevant to both axles not just the rear.


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## colinm (Aug 27, 2021)

barge1914 said:


> Do you know why Tyresafe always quote 80 for rear? Michelin do also, but Continental give pressures according to true axle weight.


It's some kind of liability problem, the original tyres on my van where supposedly built as CP but they are not allowed to mark them as such, so I fill in the form as C tyres and they give lower pressure, I fill it in as CP and it gives the higher figure.
p.s. my original tyres where Conti 215/75C16, if they where to CP regulations they would not be up to the axle loads.


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## mark61 (Aug 27, 2021)

Shame the tyresafe site just list rubber bands, not decent tyre sizes    
Would be interesting.


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## barge1914 (Aug 27, 2021)

colinm said:


> It's some kind of liability problem, the original tyres on my van where supposedly built as CP but they are not allowed to mark them as such, so I fill in the form as C tyres and they give lower pressure, I fill it in as CP and it gives the higher figure.
> p.s. my original tyres where Conti 215/75C16, if they where to CP regulations they would not be up to the axle loads.


For my Continental CP tyres on previous van Continental were happy to recommend pressures appropriate to axle load on both front and rear, which was a lot less than 80psi.


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## colinm (Aug 27, 2021)

barge1914 said:


> For my Continental CP tyres on previous van Continental were happy to recommend pressures appropriate to axle load on both front and rear, which was a lot less than 80psi.


Yes Conti will still recommend pressures for load, as for Michelin, some years back they did the same, I read that they had become risk adverse due to motorhome users asking for pressures at specific load then subsequently upping load without increasing pressures.


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## barge1914 (Aug 27, 2021)

colinm said:


> Yes Conti will still recommend pressures for load, as for Michelin, some years back they did the same, I read that they had become risk adverse due to motorhome users asking for pressures at specific load then subsequently upping load without increasing pressures.


I can understand that. But on a van like mine that would result in pressure (80 psi) intended for a 2000kg axle, that is not actually permitted to be loaded above 1750kg because for the UK market the total load is down rated to 3500kg from the 3650kg at manufacture. The result is lightly loaded rear wheels inflated to give little contact area and consequently poor braking increasing the risk of rear wheel skid… or am a wrong in that interpretation. I want a real solution, not one that is designed to protect the tyre makers backside.


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## molly 2 (Aug 28, 2021)

Their are 2 great mysteries on WC 1 is what are my tyre pressures 2 why is my battery flat


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## GMJ (Aug 28, 2021)

Big Chief said:


> If you want to know what tyre pressures to run then take a look at this website https://www.tyresafe.org/motorhome-tyre-pressure/



This site has an option for single or twin axles however does anyone know if you put in the weight for 1 axle or the 2 combined (so for me it would be 1600kg or 3200kg as I have a tag axle MH)?

ta


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## maingate (Aug 28, 2021)

GMJ said:


> This site has an option for single or twin axles however does anyone know if you put in the weight for 1 axle or the 2 combined (so for me it would be 1600kg or 3200kg as I have a tag axle MH)?
> 
> ta


For a Tag axle it has front, axle 1 and axle 2. Input each individual axle weight.


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## GMJ (Aug 28, 2021)

Not on mine. Am I doing something wrong?


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## Val54 (Aug 28, 2021)

Don't think so, I get the same page and options. 

I have to say I get confused by this site, they state ....

"CP-type tyre construction enables the use of higher inflation pressures to provide resistance to the difficult conditions of use encountered on motorhomes. Therefore, when CP-type tyres are fitted on the rear axle in a single formation set the inflation pressures to 5.5 bar (80 psi) for all loads."

However, I'm not sure what they mean by "difficult conditions of use".  I have CP rated tyres fitted so obviously get a result of 80psi on the rear axle, if I change the rating to "C" with the same tyre size and axle load I can drop the pressure to 59psi.


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## maingate (Aug 28, 2021)

They have updated the website since I last used it but I got a result.

On a tag axle both axles are identical and usually have a rating of around 1500 Kg. I just inputted my front axle weight and the weight of one tag axle and got the correct pressures.


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## trevskoda (Aug 28, 2021)

Well im leaving mine at 65psi as having double back wheels and there will never be 3 ton of lib books in it, anyway the tyres wear even across the tread, just a pity there expensive if you buy new,


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## QFour (Aug 29, 2021)

This is on the diesel door of our Carthago


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## GMJ (Aug 29, 2021)

maingate said:


> They have updated the website since I last used it but I got a result.
> 
> On a tag axle both axles are identical and usually have a rating of around 1500 Kg. I just inputted my front axle weight and the weight of one tag axle and got the correct pressures.



If I do that I get 65psi for the front but only 40Psi for the back...which seems a tad low to my mind

If I add the 2 axles together and put that in I get 65Psi all round!


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## trevskoda (Aug 29, 2021)

QFour said:


> This is on the diesel door of our Carthago View attachment 101451


Can you get petrol doors?


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## Val54 (Aug 29, 2021)

QFour said:


> This is on the diesel door of our Carthago View attachment 101451


That's interesting, clearly Carthago don't have a problem with using "C" rated tyres, is that on an Alko chassis or Fiat?


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## maingate (Aug 29, 2021)

GMJ said:


> If I do that I get 65psi for the front but only 40Psi for the back...which seems a tad low to my mind
> 
> If I add the 2 axles together and put that in I get 65Psi all round!


Look at the photo above your last post of the Cathargo tyre pressures for various loads. Therre are some low pressures on that chart. You have not said what size tyres you have.

Edited to add that when I put 4 new tyres on the back 2 axles, I used Commercial Agilis and not CP tyres.


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## Val54 (Aug 29, 2021)

GMJ said:


> If I do that I get 65psi for the front but only 40Psi for the back...which seems a tad low to my mind
> 
> If I add the 2 axles together and put that in I get 65Psi all round!


That does sound low for the rears, but bearing in mind the rear axles are sharing the load I would expect the rear tyre pressures to be lower than the fronts unless the weight distribution is very uneven.


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## maingate (Aug 29, 2021)

Val54 said:


> That does sound low for the rears, but bearing in mind the rear axles are sharing the load I would expect the rear tyre pressures to be lower than the fronts unless the weight distribution is very uneven.


My tyres are 225/65 R16 CP (C on the back axles). Tyresafe give the pressures as Front 62 psi, Rear 44 psi.

I run at Front 65, Rear 50. I added a few pounds as I have alloy rims which can very slowly bleed off a bit of pressure over time.

At the moment my van is totally empty as I have put it up for sale. With nothing on board it rattles a lot more when I drive it. I am thinking of reducing the tyre pressures as it may put prospective buyers off a bit.


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## GMJ (Aug 29, 2021)

maingate said:


> Look at the photo above your last post of the Cathargo tyre pressures for various loads. Therre are some low pressures on that chart. You have not said what size tyres you have.
> 
> Edited to add that when I put 4 new tyres on the back 2 axles, I used Commercial Agilis and not CP tyres.



225/75R16CP Michelin ones


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## maingate (Aug 29, 2021)

GMJ said:


> 225/75R16CP Michelin ones


If you are happy at that pressure then stick with it.

You could always try an old fashioned test to see what contact you have with the road. Find a bit of new smooth tarmac. Measure the width of tread across the tyre. Put a chalk mark across the tread and roll the wheel forward a revolution, then check the chalk mark on the road. It should be the same length and evenly distributed as the tyre. If the mark is shorter, you are over inflated. If the mark is fainter in the middle, you are under inflated


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## Big Chief (Aug 30, 2021)

barge1914 said:


> That tells me 53psi front and 80psi rear but for full plated loads. But actual rear is 1600, and for gross vehicle weight I can only put 1700kg on rears….so still unsure.


If you contact them then they will calculate the correct pressures for you


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## Val54 (Aug 30, 2021)

Big Chief said:


> If you contact them then they will calculate the correct pressures for you


If they are Michelin CP, tech support will only calculate the front axle and tell you 80psi on the rear.


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## barge1914 (Aug 30, 2021)

Val54 said:


> If they are Michelin CP, tech support will only calculate the front axle and tell you 80psi on the rear.


That’s exactly what they did. For a van with a large rear overhang and all the storage at the back that may make some sense. But with a van heavy at the front and with a low allowable max load at rear I can see no logic in it.


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## Val54 (Aug 30, 2021)

barge1914 said:


> That’s exactly what they did. For a van with a large rear overhang and all the storage at the back that may make some sense. But with a van heavy at the front and with a low allowable max load at rear I can see no logic in it.


The only explanation I could get was that CP rated tyres are reinforced, particularly on the sidewalls,  to help prevent degradation when standing for long periods. To achieve this Michelin say they have to be kept at max pressure i.e. 80psi. I will be switching to Continentals next time as their camper tyres can run at lower (more comfortable) pressures. One option might be to run the Michelins at the equivalent C rating pressure on the road and pump them back up to 80psi when left for long periods ?


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## wildebus (Aug 30, 2021)

Val54 said:


> The only explanation I could get was that CP rated tyres are reinforced, particularly on the sidewalls,  to help prevent degradation when standing for long periods. To achieve this Michelin say they have to be kept at max pressure i.e. 80psi. I will be switching to Continentals next time as their camper tyres can run at lower (more comfortable) pressures. One option might be to run the Michelins at the equivalent C rating pressure on the road and pump them back up to 80psi when left for long periods ?


Michelins approach makes sense for the typical Motorhome user I would say ...

How many people actually check their tyre pressures on a regular basis and/or adjust them for differing loads and circumstances (very few.  Cue the "you should check before each journey and weekly" responses, but we live in the real, failed, world).
And what proportion of Motorhomes spend 90% of their life stationary on a driveway or storage facility - and 90% of the remaining 10% stationary on a Campsite?  (the great majority of them I reckon - just need to look at the mileages of ones for sale ... 10,000 miles on a 10 year old van for example).

For THOSE users, the features of the Michelin 'Camping' spec tyres seem right and maybe the design of these tyres means they should actually be run at 80 PSI in use as well as when parked?
I don't know.  Does anyone other than Michelin?  Why should an individual user know better than the maker of the product?  Michelin will say nothing other than 80PSI.   They presumably have a reason for this stance I would imagine?

FWIW, I use Michelin Aglis Tyres on my Motorhome, but I run the Aglis Cross-Climates as they are (IMO) much more suitable for my location, being all-season tyres.  The Aglis Camping Tyres are designated as 'Summer' Tyres.  Come the Winter - or in Scotland, most of the year (seriously) - when average temps fall below 7C, the use of Winter Tyres is recommended, and this is where the Cross-Climates come into play rather than having to have 2 sets of tyres.  It is not just about ice and snow, but temperature as well.

The Aglis Camping Tyres again are designed for the typical Motorhomer - the ones that only use their vehicles in the summer and usually head to warmer places to boot.   All-year users should (again, IMO) look to fit all-season tyres.


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## trevskoda (Aug 30, 2021)

I have just bought of flea bay 4 mud snow winter tyres as most of the year here is wet cold and roads covered in farmers slurry droppings, I think.


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## Val54 (Aug 30, 2021)

Only guessing, but Michelin probably don't want a lawsuit resulting from an accident involving a heavily overloaded van with their "calculated" rear axle tyre pressure, so they play safe, I don't blame them.
What I still can't understand is if CP rated tyres have to run at 80psi,  why can their normal commercial tyres run at lower pressures with the same axle load despite being "less reinforced" ....... we all use the same "pot holed" roads  Answers on a postcard please!


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## wildebus (Aug 30, 2021)

trevskoda said:


> I have just bought of flea bay 4 mud snow winter tyres as most of the year here is wet cold and roads covered in* farmers slurry droppings*, I think.


I won't be the farmers droppings     unless he is a Motorhomer as well of course, in which case he will be flinging it everywhere (think I read that in the BallyCastle Daily Mail?)


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## forthpilot (Aug 30, 2021)

Rear wheel drive on a Sprinter, 3500 kg. Michelin Agilis CP 225/70/R15C 112, with 55 front and 65 rear, comfortable.
Tried the recommended 82 psi and very uncomfortable and noisy. I use the TyreSafe graph and adjust 
the pressures if any major changes before going away.


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## barge1914 (Aug 30, 2021)

Val54 said:


> Don't think so, I get the same page and options.
> 
> I have to say I get confused by this site, they state ....
> 
> ...


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## barge1914 (Aug 30, 2021)

Once my camper tyres are worn out I’ll be replacing with all-season m+s 3 Peak ones. Unfortunately when I bought it I couldn’t persuade the dealer to supply it with these, and I can’t persuade myself to spend £5-600 on another set and flog the CPs off at a great loss.


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## colinm (Aug 30, 2021)

barge1914 said:


> Once my camper tyres are worn out I’ll be replacing with all-season m+s 3 Peak ones. Unfortunately when I bought it I couldn’t persuade the dealer to supply it with these, and I can’t persuade myself to spend £5-600 on another set and flog the CPs off at a great loss.


And if they are Michelin CrossClimate they will tell you not for use on Motorhomes, been there, done that, phone conversation.


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## mark61 (Aug 30, 2021)

Michelin USA don't have any problem promoting the Agilis CrossClimate for RV's.
It is possible it's not the same tyre of course.
Important to include the model name Agilis. 

https://www.michelinrvtires.com/tir...NlIWZhbHNlIWZhbHNlIXNlbGVjdG9ybmFtZSFaITEwITE


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## Glynno (Aug 30, 2021)

Fisherman said:


> Apologies for bringing up a subject discussed many times on here.
> I have mitchelin agilis tyres which I run at 65psi.
> My van is a 3.5T ducato a class.
> But once warmed up after a few miles they rise to around 72psi.
> ...


Your tyre pressure will rise after a run due to heating of the rubber. I think tyres should be inflated when cool As they are cool when fitted then blown to correct pressure. I keep mine at 65 and check before trip rather than on trip.


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## colinm (Aug 30, 2021)

mark61 said:


> Michelin USA don't have any problem promoting the Agilis CrossClimate for RV's.
> It is possible it's not the same tyre of course.
> Important to include the model name Agilis.
> 
> https://www.michelinrvtires.com/tir...NlIWZhbHNlIWZhbHNlIXNlbGVjdG9ybmFtZSFaITEwITE


This is the specific tyre I asked about.








						Michelin Agilis CrossClimate 215/75 R16 R tyres | Blackcircles.com
					

Buy tyres online and get them fitted locally with Blackcircles. Lifetime Guarantee now on all car, van & SUV tyres. Peace of mind, at no extra cost.



					www.blackcircles.com
				



As with all tyres in this size there is no CP tyre which is up to the job for our van.


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## Harryw (Aug 30, 2021)

Tyresafe also say for CP tyres the rear is 80psi regardless. See their leaflet too;


			https://www.tyresafe.org/wp-content/uploads/2017/08/Motorhome-leaflet-FINAL.pdf?fbclid=IwAR2g_xovoqxggU1Dyr8Od4b5x1te4U8O54rz-BuNKT1p-6NoOjnJH3pvb8I


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## Val54 (Aug 30, 2021)

colinm said:


> This is the specific tyre I asked about.
> 
> 
> 
> ...


Would the rims not take 225 width instead? I seem to remember there is a bit of flexibility in the tyre width fitting from my youthful motoring days ............


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## colinm (Aug 30, 2021)

Val54 said:


> Would the rims not take 225 width instead? I seem to remember there is a bit of flexibility in the tyre width fitting from my youthful motoring days ............


They would, but I was interested as to what Michelin would say, it was obvious that it was a case of "Computor says", as the person answering said I should use CP tyres, when I pointed out these where not rated to the axle load they gave up and said they didn't have a suitable tyre to offer, as it happens the van came from Globecar with Conti's fitted, in this size they are marked as C, but are built as a 10ply CP tyre, there are thousands of PVC's where the base vehicle is supplied by Fiat to large convertors with C tyres.


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## barge1914 (Aug 30, 2021)

colinm said:


> And if they are Michelin CrossClimate they will tell you not for use on Motorhomes, been there, done that, phone conversation.


Used to use Vredestein, they were happy for them to be used on Moho.


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## wildebus (Aug 31, 2021)

Filled 100% with Fresh Water and put bike on rear rack and paid a visit to the local weighbridge so I could then check pressures on the tyresafe site ....


Currently got 2120Kg on the Rear and 1520Kg on the front, giving me 210Kg payload left, so not too bad - except weights don't include any people.  But reckon two people and a full fuel tank (currently half full) would still see us under the limit.   And could easily travel with the fresh tank only half-full if need be.

Put in weight to take to 3850Kg, with the rear axle at the limit as well as adding all the spare payload plus a bit more at the front end up with this:





Surprisingly low on the front and a bit lower than I would have expected at the back

Checked the pressures when I got back home (total distance from home to WB to home again was maybe 8 miles?)



Will check the pressures from "proper" cold in the morning, but looks like I could reduce the fronts and check (even out at least) the rears  - I don't think ~22C is the tyres warmed up very much so pressure is likely 65PSI (what I originally set in fact).


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## gasgas (Sep 1, 2021)

edit: I thought I was replying to a previous post but the quote didn't come up. So forget it. I just use the pressures on the door post label, I don't see anything wrong with that.
Oh and by the way did you know that if you have a new - ish motorhome with a TPMS then it has to be working properly for the MOT? Reason number two thousand nine hundred and eighty six not to buy a new motorhome.


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## colinm (Sep 2, 2021)

gasgas said:


> I just use the pressures on the door post label, I don't see anything wrong with that.


Our van, like many others, is built on a Maxi chassis but only licenced for 3.5t. The door pillar pressures are for axle loads which add up to 4.5t, considerably higher than we can legally use, let alone those we actually run at.


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## trevskoda (Sep 2, 2021)

If the tyre wears even across the tread then the psi you are running is correct, 5 or so psi either way wont make a blind bit of differance.


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## QFour (Sep 2, 2021)

Val54 said:


> That's interesting, clearly Carthago don't have a problem with using "C" rated tyres, is that on an Alko chassis or Fiat?


Alko chassis.


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## QFour (Sep 2, 2021)

trevskoda said:


> Can you get petrol doors?


Yep they are a bluey colour


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## QFour (Sep 2, 2021)

gasgas said:


> edit: I thought I was replying to a previous post but the quote didn't come up. So forget it. I just use the pressures on the door post label, I don't see anything wrong with that.
> Oh and by the way did you know that if you have a new - ish motorhome with a TPMS then it has to be working properly for the MOT? Reason number two thousand nine hundred and eighty six not to buy a new motorhome.


Ours is newish 2020 and doesn't have TPMS. Think it's an option when ordering Fiat Cabs


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## gasgas (Sep 8, 2021)

I would imagine it comes as a non-option if you want the 'de-luxe' pack of Remis blinds, cab air con, and the seemingly non-optional alloy wheels which look fabadabadozy in the showroom but take an hour each to clean later.


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## colinm (Sep 8, 2021)

After writing my


gasgas said:


> So forget it. I just use the pressures on the door post label, I don't see anything wrong with that.





colinm said:


> Our van, like many others, is built on a Maxi chassis but only licenced for 3.5t. The door pillar pressures are for axle loads which add up to 4.5t, considerably higher than we can legally use, let alone those we actually run at.


After writing my reply something occurred to me, for decades now my cars have had three different pressures on the door pillar label, one for light load, one for maximum load, and one for economy, and yet for vans Michelin only ever consider the tyres should be at maximum pressure which might well be way over that needed.


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## campervanannie (Sep 8, 2021)

On my Rapido weight 3.875 I run my Michelin Agilis 60 at the front and 65 at the rear 
Why?
Because the man that fitted them told me to.


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## Markd (Sep 10, 2021)

Continental do a fantastic tyre data book tha gives tyre pressures for load on many many tyres.
It is best viewed on a computer screen to get double pages lined up.
Obviously manufacturer specific but with Ply Rating and size I would be prepared to use it for other premium brands.

It's very comprehensive and full admit to being too lazy to edit up the most likely sections - have fun browsing


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## QFour (Sep 10, 2021)

Carthago have 5 pages of tyres and tyre pressures to pick from Zw is for tag axle


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## trevskoda (Sep 10, 2021)

One tyre said to the other, im under a lot of pressure today how about you.


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## Markd (Sep 10, 2021)

Pleased that Cathargo have engaged brain - see a page published in another thread recently.


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## QFour (Sep 11, 2021)

Markd said:


> Pleased that Cathargo have engaged brain - see a page published in another thread recently.


Possibly on the Bailey forum I have been trying to educate them but they are a reluctant bunch. Just because it says 80psi on the MH that's what it should be. Then they wrap everything in teatowls and bubble wrap.


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## Pudsey Bear (Sep 11, 2021)

I like my pressures in PSI 0.5 bar = 7.5 PSI so not very accurate.


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## molly 2 (Sep 11, 2021)

I use what it says on the tin  .


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## gasgas (Oct 5, 2021)

If you are going to get too fussy about weight and tyre pressures then you will need to adjust your tyre pressures each time you fill up with diesel, each time you go shopping, each time you fill the water tank / empty the grey tank and each time you empty the cassette. Then of course you will have to set the pressures before you set off in the morning and adjust them at noon after a hundred miles of driving.


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