# Definitive Answer to Tyre Pressure



## WildThingsKev

Look what I found on the tyre industries "TyreSafe" website. A special document giving their recommended pressures and lots of useful info and safety advice for Motorhomes.

http://www.tyresafe.org/data/files/motorhome 08.pdf

It lists Light Commercial and Camper tyres in separate tables as well as twin wheel axles. I note that the Camper pressures given for my Rapido X250, though higher than the Lt Comm, are still much less than those given on my door pillar! (5 and 5.5bar).

Kev


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## Vita

*Difinitive answer to tyre pressure*

Excellent!


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## Wizzo

Well done for bringing this up. It has been highlighted on the forum before but it is a very useful document. Unfortunately it doesn't cover all the tyre sizes used on motorhomes but it should nevertheless provide a useful guide to correct pressures.

The other thing to bear in mind is that to be accurate you need to know the actual axle weights in normal running trim so a visit to a weighbridge is useful.

JohnW


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## loughrigg

Nice to have some confirmation - the pressure suggested on the table is about 2 psi away from the figure I worked out myself.

Mike


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## teemyob

*Info*

All that information, yet no mention of the Popular FWD TAG Axle!

How odd.....


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## Groper

Thank you.Really useful article.

Clive


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## andygrisswell

What if like me you have a tag axle front wheel drive with 215/70/16 tyres


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## RichardnGill

Tags are a bit harder to calculate pressure for and many tyre manufactures will simple advise very high pressures for them due to axel scrub.

With most Tags the rear axels only run at about 1500,Kgs so if you calculated pressures from the chart in the link you would find that 60 Psi is more than enough and will give you a margin for scrub.


One word of caution though is if you travel in the alps or other very hilly areas and spend a lot of time on the steep hills you might need to increase your pressures by 10% as your axel weights will change especially when braking down the long hills. 

Some calculation charts take this into consideration and some dont, this chart does not say anything about braking over loading etc.


Richard...


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## Chudders

Richard, I also have a FWD tag axle and have pondered over the tyre pressures. What is 'scrub' that yo refer to
Dave


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## RichardnGill

If you were to set your tyre pressure using just weight as the calculation for a tag you might find that your pressure calculation could be as little as 40 Psi. This would be find until you were on full lock turning around a tight corner. Then the tyre would scrub and if the pressure was only just sufficient to hold the load you might have problems with the tyre flexing too much. 

The cure to this is to increase the tyre pressure, how much depends on the actual load and how far apart the axels are. That is why you will find that many tyre manufacture will advise very high pressures as they do not know what the axel spacing is etc.

On AlKO chassis tags the axel are very close so the problem is minimal. 


Richard...


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## Pard

Great! Really helpful.

Thanks.


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## peribro

I've got Continental 225/75/R16 CP tyres and e-mailed Continental for their advice. Within a few hours I received the reply below:

"For tyres with the service description: 116/114N(110S) - 116/114R(118/116P)
& 116R

Front:
3 bar - 43psi which carries a maximum load of 1730kg

Rear:
4.5 bar - 65psi which carries a maximum load of 2395kg


For tyres with the service description: 118/116R & 121/120R

Front:
3 bar - 43psi which carries a maximum load of 1685kg

Rear:
4.75 bar - 69psi which carries a maximum load of 2435kg"


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## andygrisswell

front wheel drive tag axle 65 psi all round and never had a problem.


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## ingram

Wizzo said:


> The other thing to bear in mind is that to be accurate you need to know the actual axle weights in normal running trim so a visit to a weighbridge is useful.
> 
> JohnW


I don't change my car tyre pressures according to how many people I carry or how much weight I have in the boot.

I don't with the motorhome either. I sometimes drive it 'empty', lightly loaded for short trips away. more heavily loaded for longer trips.

Just use tyre pressures from this guide or other sources assuming maximum axle loads and you'll be fine: you only need to weigh the damned thing to ensure that you are not *overloaded* when fully loaded................. just of course, my own opinion but all this 'weighbridge' talk worries some people needlessly.

Harvey


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## nicholsong

Thanks for link to Tyresafe but when I either click on link or go direct to URL address and then navigate to MH section I get message that file is damaged and cannot be repaired.

Any help appreciated.

Geoff


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## nicholsong

Thanks for link to Tyresafe but when I either click on link or go direct to URL address and then navigate to MH section I get message that file is damaged and cannot be repaired.

Any help appreciated.

Geoff


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