# 80 psi in tyres ? is that right ?



## roadwarrior1

when i bought my ducato van a few weeks ago the tyres were 55 psi all round, im sure i read somewhere it should be 60 psi - now i find a sticker on the door by fiat saying 80 psi front ?


----------



## bigcats30

what does it say in the user handbook?


----------



## dovtrams

If you put them to 80 you will take up ice skating. There are lots of threads about this and how to calculate tyre pressures. I went down the weighbridge, continental tech dept and this week when my vehicle was in for its first MOT the garage said the tyres areunder inflated at 50 and 60 psi and recommend another 5psi in each.

dave


----------



## Blizzard

Tyre pressures for my Ducato in the AlKo handbook are 5.5 bar (79.8psi) all round.


----------



## motormouth

bigcats30 said:


> what does it say in the user handbook?


The vehicle handbook will give recommended pressures for the base vehicle in chassis cab form and not for Motorhome use. The same applies for any pressures shown on the plate inside the door frame/under the bonnet. I think I am right in saying that very few Motorhome convertors will give recommended pressures.

The best advice readily given in dozens of similar queries is to take vehicle to weighbridge and get weights for front axle, rear axle and whole vehicle making sure it is fully laden with everything you would normally take away with you including full tanks, gas bottles, generators, bikes, scooters, spouse, kids, dogs etc etc.
Then email these weights along with exact tyre sizes to the tyre manufacturer. Most will respond with exact pressures.


----------



## cronkle

As others have said, load up and go to the weighbridge.

If your tyre manufacturer is unwilling to help (some are and some aren't) consult this:

http://www.tyresafe.org/images/tyre-safety-guide/motorhome-leaflet.pdf


----------



## bigcats30

motormouth said:


> bigcats30 said:
> 
> 
> 
> what does it say in the user handbook?
> 
> 
> 
> The vehicle handbook will give recommended pressures for the base vehicle in chassis cab form and not for Motorhome use. The same applies for any pressures shown on the plate inside the door frame/under the bonnet. I think I am right in saying that very few Motorhome convertors will give recommended pressures.
> 
> The best advice readily given in dozens of similar queries is to take vehicle to weighbridge and get weights for front axle, rear axle and whole vehicle making sure it is fully laden with everything you would normally take away with you including full tanks, gas bottles, generators, bikes, scooters, spouse, kids, dogs etc etc.
> Then email these weights along with exact tyre sizes to the tyre manufacturer. Most will respond with exact pressures.
Click to expand...

he didn't say motorhome he said van


----------



## motormouth

bigcats30 said:


> motormouth said:
> 
> 
> 
> 
> 
> bigcats30 said:
> 
> 
> 
> what does it say in the user handbook?
> 
> 
> 
> The vehicle handbook will give recommended pressures for the base vehicle in chassis cab form and not for Motorhome use. The same applies for any pressures shown on the plate inside the door frame/under the bonnet. I think I am right in saying that very few Motorhome convertors will give recommended pressures.
> 
> The best advice readily given in dozens of similar queries is to take vehicle to weighbridge and get weights for front axle, rear axle and whole vehicle making sure it is fully laden with everything you would normally take away with you including full tanks, gas bottles, generators, bikes, scooters, spouse, kids, dogs etc etc.
> Then email these weights along with exact tyre sizes to the tyre manufacturer. Most will respond with exact pressures.
> 
> Click to expand...
> 
> he didn't say motorhome he said van
Click to expand...

So he did :roll: But I would have thought that as this is a Motorhome forum, and the OP has got a Motorhome, he may have been referring to a Motorhome which some people refer to as vans. :wink: :wink:


----------



## Dougaitken

Hi

Got these figures from Continental Tyres today.

Van (sorry Motorhome) 3500KG Max Fiat Ducati base, Front wheel drive

Tyres 215/70 R 15 CP

Front Axle @ 
Max 1850 kg recommended pressure 4.25 bar 
for a load of 1795 kg = 4.00 bar 

Rear Axle @ 
Max 2000 kg Recommended pressure = 4.75 bar 
for a load of 1885 kg = 4.25 bar 

I believe Mitchelin recommended higher pressures on their tyres.

Doug


----------



## Sprinta

motormouth said:


> bigcats30 said:
> 
> 
> 
> 
> 
> motormouth said:
> 
> 
> 
> 
> 
> bigcats30 said:
> 
> 
> 
> what does it say in the user handbook?
> 
> 
> 
> The vehicle handbook will give recommended pressures for the base vehicle in chassis cab form and not for Motorhome use. The same applies for any pressures shown on the plate inside the door frame/under the bonnet. I think I am right in saying that very few Motorhome convertors will give recommended pressures.
> 
> The best advice readily given in dozens of similar queries is to take vehicle to weighbridge and get weights for front axle, rear axle and whole vehicle making sure it is fully laden with everything you would normally take away with you including full tanks, gas bottles, generators, bikes, scooters, spouse, kids, dogs etc etc.
> Then email these weights along with exact tyre sizes to the tyre manufacturer. Most will respond with exact pressures.
> 
> Click to expand...
> 
> he didn't say motorhome he said van
> 
> Click to expand...
> 
> So he did :roll: But I would have thought that as this is a Motorhome forum, and the OP has got a Motorhome, he may have been referring to a Motorhome which some people refer to as vans. :wink: :wink:
Click to expand...

my MH is called 'The Truck'


----------



## lesanne

look at the tyre manufacturers recomendations written on the tyres as all makes are different..Les


----------



## bigtwin

Tyre pressures recommended by Michelin for my vehicle :

Front (1726Kg) - 54psi

Rear 1 (1358Kg) - 72psi
Rear 2 (1336Kg) - 72psi

The front is lower than the pressure I was running and the ride has substantionally improved (less jarring over bumps/ripples).


----------



## roadwarrior1

thank you gentlemen - yes indeed i have a ducato based Autotrail Cheyanne 635 MH and i do call it a van :lol: 
anyway, i have ignored fiat's wisdom of 80 psi as i also agree skating might be on the menu as well as very bumpy ride. 
But it makes no sense as a MH is waaaay heavier than a normal fiat van - im basing my 60 psi on the weight of my old caravan - around 1400 kilos (one axle) - so yes i will get it wieghed - but rather assumed with the wealth of knowledge here someone would know for my particular MH

speaking of which ... do we need " special" tyres ? or normal van tyres good enough ? I intend to be using it regularely - and not idle for months and creating square tyres.. :roll:


----------



## TR5

roadwarrior1 said:


> speaking of which ... do we need " special" tyres ? or normal van tyres good enough ? I intend to be using it regularely - and not idle for months and creating square tyres.. :roll:


You'll get various views on that question, i'm sure.
I understand that 'Camping' tyres have extra ply's in the sidewalls to minimise the risk of flat-spotting, due to motorhomes often standing for long periods on one part of the tyre.

Personally, I think any van tyre that is both weight and speed ratings suitable for the vehicle, i.e. adequately exceeds the maximum axle weight per tyre, then these are fine, especially if used / moved regularly.

I am a little confused by the pressures given in the example by 'BigTwin' - the rear tyre pressures appear to be much higher than I would expect for the axle loading, but perhaps that's because there are two axles / tyres together, and the drag on the tyres when cornering may determine thet they run at a higher pressure to reduce road contact and drag - I don't know. Could be a hard ride, though!

A good guide in my opinion is to work out what percentage of the weight limit of the tyre is the maximum axle weight, and use that same percentage to work out the tyre pressure against the maximum working pressure of the tyre.


----------



## jonus

I'm far from knowlegeable but...Isn't the max [email protected] written on the side of the tyre?


----------



## TR5

It certainly is. That's why you can use the percentage calculation to get fairly accurate guide to tyre pressure details.

i.e. If the max pressure/load is 80psi at say 2000kg......
and your axle load per tyre is 1500kg, that is 75% of max load....
so 75% of 80psi is 60psi.


----------



## Wizzo

roadwarrior1 said:


> speaking of which ... do we need " special" tyres ? or normal van tyres good enough ? I intend to be using it regularely - and not idle for months and creating square tyres.. :roll:


I have recently bought a Apache 634L which was fitted with Continental Vanco 'Camper' tyres. I have had to change the tyres to a slightly wider size in order to increase the load index (I am currently uprating the rear axle load). I have now had fitted Toyo H09 all round. The difference in ride quality is amazing. The Toyos, which are a 'commercial' tyre rather than a 'camping' tyre are much more pliable and no longer crash and bang over the bumps and potholes. A much quieter ride, and I am running at similar pressures to the old set (54psi all round at present).

So my advice is to use commercial tyres and even look at using a M&S rated tyre such as the Toyo H09 which will be much better in 'offroad' 
situations.

I bought my tyres through Tyre-shopper (£101.00 a piece, fitted)

JohnW


----------



## SwampThing

I am also in the process of working out the best pressure for the tyres on our motorhome.
We have an A class Rapido which is running on Vredestein Comtrac All Weather tyres (225/70R15 112R)
I went to our local weighbridge and, all up in holiday trim with SHMBO on board weights were Front axle 1700Kg, Rear Axle 1520Kg
Looking at the tyresafe link provided in an earlier post, this indicates pressures of around 48psi front, 42psi rear
I also contacted Vredestein and gave them the axle weights. They advised 65psi front and rear which is simply the max pressure rating of the tyre.
Somewhat puzzled but I am currently using the 65psi as recommended as that seems safest.
This definitely seems to be an area where general confusion reigns!


----------



## WhiteCheyenneMan

I'm happy to trust my dealer's technician. He really is very knowledgeable and very good. I was running my Ducato/Alko based Cheyenne 740SE with safety bar, tow bar, spare wheel, 2/3 passengers and a not quite full load at the cab label's 80psi.
Tom the technician said "That's too high so I've reduced it to 75psi".
Result, no change in already good grip but a much quieter, smoother ride. And that's just down by 5psi.
I have Tyrepal fitted and it's interesting to see how much the pressures rise on a trip. The rear tyres may start at the same pressure, but the nearside always rises higher than the offside. Possibly because the fridge, freezer and boiler are on that side? Both rear tyres rise more in pressure than the front, presumably because there's way more weight on the rear, especially with its large overhang.


----------



## Rapide561

*Tyres*

Hi

I run at 80 psi all round - Kontiki tag axle.

Russell


----------



## BrianJP

TR5 said:


> It certainly is. That's why you can use the percentage calculation to get fairly accurate guide to tyre pressure details.
> 
> i.e. If the max pressure/load is 80psi at say 2000kg......
> and your axle load per tyre is 1500kg, that is 75% of max load....
> so 75% of 80psi is 60psi.


Sorry but it is not an exact science as you seem to think. It depends on may variables and I have posted many times before regarding this. Only accurate way to ascertain correct pressures is to go to weighbridge fully loaded or use max front and rear axle loads as a guide then ask tyre manufacturer for correct pressures. In case of Conintentals they will freely give info and I have a copy of their Handbook which I will willingly send to enyone else if they give me their mail address via pm. Note Base vehicle tyre pressure label gives max pressures only usually 5.5Bar 80psi only which usually way ton high for most Mh's.,

Note for moderators can I please upload the Conti Tyre handbook to the site as it will be of use to many other members ?


----------



## trevd01

The 109 rated Pirellis on our van say max pressure @ 1030kg = 70psi.

I base my pressures on that, having weighed the fully loaded van (axles separately).

Aren't all tyres marked like this?


----------



## BrianJP

trevd01 said:


> The 109 rated Pirellis on our van say max pressure @ 1030kg = 70psi.
> 
> I base my pressures on that, having weighed the fully loaded van (axles separately).
> 
> Aren't all tyres marked like this?


Yes the tyres are all marked similarly however with camper specific tyres they can be marked differently. eg Continental CP tyres are marked as 69psi for 1030kg with a max inflation of 80psi ( after consulting their tables)whereas the Michelins seem to be marked as 80psi max for 1030kg.


----------



## Easyriders

Our 2.3 Fiat MH has the recommended tyre pressures on a label on the door, and in the Adria handbook. They are 56 front and 60 rear.


----------



## BrianJP

Easyriders said:


> Our 2.3 Fiat MH has the recommended tyre pressures on a label on the door, and in the Adria handbook. They are 56 front and 60 rear.


Well you are lucky.
As many other MH owners have found out including the OP, many Mh's only have a base vehicle manufacturers sticker on the drivers door with max tyre pressures ,typically 80psi.
Also as in my case ( A Rapido) ) when you contact the MH manufacturer for info as there is nothing in the owners handbook , they refer you back to the base vehicle manufacturer.
Full circle eh? thats why so many people are looking for the correct info. Hence my previous post and many other members in other threads on this subject.


----------

