# Tyre pressures



## Lilliput (Oct 26, 2010)

Hi

We have a 2007 Dethleffs Globebus T3 on a Fiat Ducato Chassis, 2.3 TD, maximum payload 3.500Kg. The tyres are Continental Vanco 215/70 R15 CP.

I contacted Continental re recommended tyre pressures and gave the axle weights and load indices as marked on the metal tag on the inside near the door.

The recommendation was:

Front: 4.25bar - 62psi
Rear: 5.5bar - 80psi

This seems a bit excessive.

What are your views?

Thanks


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## andrewball1000 (Oct 16, 2009)

This is worth a read, particularly the 8th post by grizzzyJ

http://www.motorhomefacts.com/ftopict-101081-.html


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## Zebedee (Oct 3, 2007)

Hi Lilliput

Since my suggestion would have been to contact the tyre manufacturers, that more or less states my view. :wink: 

If they don't know - I can't think who will.

I have to agree, it sounds a bit low at the front and high at the back, but I (along with most members) am no expert.

Dave


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## jedi (Nov 22, 2007)

I have an Autotrail Apache 650 weighing just under 3500kg and the recommended tyre pressures are:

Front 72 psi

Rear 80 psi

Jed


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## peribro (Sep 6, 2009)

Lilliput said:


> I contacted Continental re recommended tyre pressures and gave the axle weights and load indices as marked on the metal tag on the inside near the door.


Whose metal tag is that? Fiat's or the van converters? If the former then it is probably not relevant. In any event you should be providing the tyre manufacturer with the weights that you are running at which will mean a trip to a weighbridge. I've looked at the Tyresafe leaflet for recommended pressures and weights for your tyres and 5.5bar is appropriate for up to 2060kgs on driven rear wheels. The maximum recommended pressure for non driven wheels is 4.75 bar with an axle load of 2060kg. The maximum weight for your fronts at 4.25 bar is shown as 1885kgs.


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## camallison (Jul 15, 2009)

My own experience with Continental has been good ....... *providing you state your ACTUAL axle weights*. Go to your local weighbridge and ask them to weigh the van per axle at running weight (packed ready to go and with the driver in the cab). Send those weights to Continental and you should get a meaningful set of tyre pressures.

When they did ours, they were spot on with ride comfort and tyre safety.

Colin

PS - remember to tell them which is the driven axle.


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## UncleNorm (May 1, 2005)

Here's the thread I started on 18 May 2010:

http://www.motorhomefacts.com/ftopict-86250-.html

I'm intrigued as to why Continental would tell me 47/61 psi and yet Lilliput comes in with 62/80.

At the end of the day, tyre pressures of motorhomes have nothing to do with the sticker on the chassis door post, or the metal tag wherever. It has everything to do with ACTUAL AXLE WEIGHTS when the MH is in 'travel trim' with everyone and everything on board.

As Colin suggests, ride quality and comfort will be much improved with the CORRECT pressures.


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## Zebedee (Oct 3, 2007)

UncleNorm said:


> tyre pressures of motorhomes have . . . . have everything to do with ACTUAL AXLE WEIGHTS when the MH is in 'travel trim' with everyone and everything on board.


Hi Uncle

If I read this correctly, assuming one member has asked the tyre people and got the pressures for his van _(*precisely as you mention above*)_ anyone else with the same or *very *similar axle weights would be advised to use the same pressures.

I can see a use for a PURELY ADVISORY database of the advice received by various members, if they were willing to pass on the recommendations they were given.

This question comes up all the time, and we may be able to pool our knowledge and develop a chart of axle weights and the corresponding recommended pressures.

(I stress it could only be advisory though. As always, it would be the sole responsibility of any member who took the advice, and subsequently had any problem.)

Do I see a willing volunteer to see if the data is out there, and to collect it if it is? :wink: 

Dave


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## EJB (Aug 25, 2007)

There is a list somewhere....I can't find it at the moment but somebody else must have it???


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## cronkle (May 1, 2005)

There is this:

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


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## Zebedee (Oct 3, 2007)

Thanks Ted and Mike

That data is a bit fiddly to interpret though.

Having to convert first to "Load Index" is a pest - could a new chart be drawn up with a direct reading from axle load to tyre pressure??

Have only glanced at it, and Mrs Zeb is on the warpath so will have to come back to this.

Dave :roll: :roll:


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## WildThingsKev (Dec 29, 2009)

Zebedee said:


> Thanks Ted and Mike
> 
> That data is a bit fiddly to interpret though.
> 
> ...


It is tyre size v axle load but the load index is listed as some tyre sizes are available in 2 different load indexes. eg 225/70 R 15 C.


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## Zebedee (Oct 3, 2007)

Thanks Kev - only glanced as I said.

Now I really must go and sort out Mrs Zeb's problem or I'm dead!! 8O 8O


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## wakk44 (Jun 15, 2006)

I contacted Continental for advice on tyre pressures and gave them all the details-axle weights,tyre type,size and load index.They replied promptly advising 45psi front and 55psi rear.

Continental were very good to deal with as well.


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## Lilliput (Oct 26, 2010)

Thank you for all your responses. I will take the MH to a weightbridge!

Cheers

Lilliput


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## bulawayolass (Jul 27, 2010)

Silly Q maybe but can we not assume the max weight and contact the manufacturer with that? 

Failing that (l have this itchy feeling the answer is no but not sure why but know someone will enlighten me)
l understand a weighbridge can do axle weights they will tell us what front and back is.
Tyre type/size l understand
But at the risk of another daft Q what is load index please 

Also the psi would then be max weight but l know l am nowhere near max weight so do l adjust pressures as needed or check with manufactures for partial weight pressures?


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## peribro (Sep 6, 2009)

bulawayolass said:


> Silly Q maybe but can we not assume the max weight and contact the manufacturer with that?


You can do but it is unlikely that you will be running at max weight on both axles. The max weight on my front axle is 2,100kgs whereas the actual weight is around 1,600kgs. At max weight we should inflate the tyres to about 60psi whereas the Continental recommended pressure for the actual weight is 44psi. I usually inflate the fronts to 50psi.



bulawayolass said:


> l understand a weighbridge can do axle weights they will tell us what front and back is.


It is worth doing because it will give you peace of mind (hopefully) and also let you know how much headroom you have - if any.



bulawayolass said:


> Tyre type/size l understand
> But at the risk of another daft Q what is load index please


 The load index, printed on the tyre sidewall, is a numerical code associated with the maximum load the tyre can carry. However your tyres should state the max load that can be carried so you shouldn't have to worry too much about the load index although watch out when replacing tyres that you get the appropriately rated ones.



bulawayolass said:


> Also the psi would then be max weight but l know l am nowhere near max weight so do l adjust pressures as needed or check with manufactures for partial weight pressures?


 As above. Best to check the actual weights and then contact the tyre manufacturer.


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## BillCreer (Jan 23, 2010)

Hi,

I posted this on a similar thread about a week ago:-

_To give you an idea of what you are dealing with I'll give you the body of two replies that I received to my request to Michelin for the correct pressures for my van and the formula they used to calculate them._

*"Based on the laden axle weights you have provided me with, I can confirm that our suggested pressures for your motorhome fitted with 215/70 R15 Agilis 2 Camping are as follows:
Front 1600kg - 53psi 
Rear 1800kg - 80psi (single axle. 72psi if tagged)."

"Unfortunately, the formula for working out the pressures for motorhome tyres is specific to individual cases and is not uniform and therefore would not be practical to give to you.
As a guide, the rear pressure should always be kept at 80psi (cold) whatever the load and it is the front pressures we adjust to help with ride comfort."
*
_It's all a bit crude isn't it? I run 55psi front and 65 rear.

I did ring the man who sent me the info and he said that recently the "Trade" had jointly decided on 80 psi at the rear, for all vehicles of that type, on safety grounds. He didn't seem totally convinced but he was conforming to the "trade" rules._


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## Lilliput (Oct 26, 2010)

*Tyre Pressures Update*

I finally took my motorhome to the public weightbridge ltoday laden for a typical trip. The individual axle weights of the vehicle were as follows:

Front: 1.5 tonnes

Rear: 1.34 tonnes

I emailed Continental and they were as helpful as usual and within hours informed me that the tyre pressures should be:

Front: 3.25bar - 47psi
Rear: 3.0bar - 43psi

Many thanks to you all who posted with your thoughts and helpful advice.

Lillput


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## UncleNorm (May 1, 2005)

Thanks for the update Lilliput. Hopefully, your bus will roll along very quietly and comfortably with those pressures. :roll: :wink:


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## Seldo (Feb 19, 2012)

I was interested in Lilliput's result from the tyre manufacturer.
I recently hired a 7.3m 6 berth Fiat Ducato MH in New Zealand and was advised by the rental company that the correct pressures were 55psi front and rear. After battling with what felt like a wallowing whale for a couple of days I reset the pressures to what I thought were correct (based on 20 years motor sport experience) and the pressures I used of 60/75 just transformed it and made it drive in a much more disciplined way.


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## motormouth (Jul 3, 2010)

It seems that we all get a bit worried about tyre pressures, rightly so.
I wonder what other road users do about pressures. I am thinking about a bus, sets off from the terminal with no passengers, ends up with 40 odd on board, do they stop off at a filling staion to adjust pressures??? Or the car transporter, sets off with 15 tonnes of cars on board, dumps them and returns empty, do they let some air out??

Or are their tyres constructed to cope with widely varying weights???


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## Philippft (Feb 16, 2008)

Please find a link to Continentals Technical Data Book for 2011-2012 below.

This contains all the information you require for correct tyre pressure.

I would have attached a copy of the book but it is too big.

http://www.conti-online.com/generat...l/download-area/download/tech_ratgeber_en.pdf


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