Tyre pressure

It's what suits your vehicle.

80 is very high for your size of Motorhome I would think, you'll know, it'll be as hard as a rock and noisy. It should say in a Hymer manual.

The problem with the manual is its all in German

Tyre pressures depend on the weight imposed on that axle and the manufacturer. I run on Michelin Agilis camping. They have extra reinforced walls and are made for standing for long periods thus the 79.5 psi. Your 65psi sounds about right but if you weigh your axles by driving your front wheels on to a weighing machine and then both ,by subtraction you separate and email the results to your tyre manufacturer ,they will give you the correct running pressures

Did the tpms not start giving low pressure warnings

NO low pressure warnings so far.

Augharan, You dont say Tyre manufacturer or type , you may be getting a smoother ride ,but at a lower pressure you will have more tyre in contact with the road surface resulting in a higher fuel usage and shorter tyre life life. You have seen how travel by rail on the bullet trains has slashed time taken but they still use iron wheels on iron rails as they did from the start of railways, because least resistance to move the load. It is better to check the tyre manufacturers recomended chart, As you will find in Bounders chart 80psi is perfectly normal in new type tyres and most importantly cut down on the roll of a caravan body when cornering.

I always wonder why the manufacturer puts the cold max psi on the side wall. Not many folk pay any heed to it, including ModernTyres.

My tyres increase by up to 10 psi on a run. This year in France the rears, which are set at the recommended 80 psi rose to 90 psi with the fronts (60 psi) doing a similar increase. The temperatures also rose but the tiny figures on the monitor are hard to read so I can’t say off the top of my head what the increase was.

Davy

Had a look at the tyres they are Vanco Camper 215 70R 15.
I have found in my 30 years of caravanning my tyres were always changed because of age not wear so at 5000 a year there will be only 25000 mls on them in 5 years. Hopefully they will last till then.
My first van an 06 Swift Kontiki was a lot more comfortable and steady on the road than the new Bailey which was a little disappointing but the lower tyre pressure has put that right, now a dream to drive.
As for fuel consumption it never changed on the lower pressure. 27 - 28 MPG.

BUT what I have found did make a difference on MPG is the diesel.
I read in some mag that you should treat your engine to a fill of Premium diesel now and again, so I decided to do that.
Almost empty I filled with the expensive stuff and didn't think anything more about it until I noticed the MPG starting to creep up.
Keeping an eye on it until the end of the fill it finished at 31.3 MPG. ( on the low Tyre pressure )
After a couple of fills with the normal diesel it's back to 27.3 again.
I suppose another fill would be interesting, so I will try it again soon .

Anybody else use the Premium stuff ??