gazz wrote:

"The Natural Philosopher" wrote in message
...
..you may remember I asked about this with reference to an Elddis
camper built on a peugeot 2 liter boxer chassis.

Having more or less eliminated the engine system as it showed up well
in CO2 tests though 4 garages failed to actually be able to access the
EMS using half a dozen different diagnostic boxes and about 50
different possible settings..teh final garage pushed teh tyres from 40
psi to 52ish..this seemed to make a slight improvement so I banged
them up to 57/62 on our recent trip, and that does seem to have got
the consumption up from 20mpg to maybe 23-24mpg..I will go the full
monty of 65 psi all round next time I have access to an airline..

I think the problem arises because the actual chassis has tyre
pressures inside the drivers door opening,but these relate to the
unloaded van, not the 3.5tonne conversion. In short anyone else
reading this who has a camper on a van chassis is well advised to
inflate the tyres to the absolute maximum - typically 65psi cold, or
even more if you dare, and ignore the safety warnings..in fact
anecdotal evidence of tyre failures suggests that hot motorway cruises
with underinflated tyres are far more likely to blow them.

the sticker on the door of the van should give tyre pressures for the
van empty and loaded, mine does,

but it's no use assuming it weighs 3.5 tons, get down a weigh bridge and
find out exactly what it weighs, go when they are not busy and get the
individual axle weights,


I prefer to look at the manufacturers website where it states that it
weighs 3.5 tonnes. Or at least the later version does. They give no clue
as to tyre pressures though.

Or just go by feel. It certainly weighs more than my 2 ton Defender used
to, but feels similar to that loaded up with a tonne of bricks and a few
people..





then e-mail the company that makes the tyres you have on the van, tell
them it's a motorhome, and the axle and total weights as well asthe
exact tyre size and model,

they will reply with suggested pressures for those circumstnaces,

Didn't need to do that. The last garage I went top had a chart for the
tyre versus various weights..

Anyway Elddis recommend pressures which are totally in conflict with the
actual weight of a standard loaded vehicle. At the very best their
pressure recommendations apply to vehicles that are totally empty - i.e.
kerb weight. Typically thats about 2.8 tonnes..but by the time you are
ready to roll, the thing is over 3..


i run goodyear cargo tyres on my motorhome (iveco turbodaily based,
weighs 4.2 tons, 1650 kilos front, rest on the back axle) goodyear told
me i'm best running 3.5 bar front and 4 bar rear, i have twin rear
wheels hence such a low rear pressure for a heavy van as the weights
spread out over 4 tyres at the back.

somewhat similar then.


yes underinflated tyres are more likely to blow, but over inflated tyres
give a hell of a bumpy ride in a motorhome, in bad cases causing the
overhead lockers to part with the walls,
but in bad cases the rock hard tyres are more likely to skid under very
hard braking, and one of the first things the vehicle inspectors do
after a bad accident is check tyre pressures.

I find that the suspension actually works on most vehicles..

I dont do hard braking either. I am not really confident that the brakes
it has are up to stopping 3.5 tonnes that quickly. Certainly locking the
front brakes would be an interesting exercise that I doubt its capable
of. i wish I could put brakes the size of my old XKR brakes in it...they
really did stop 2 tins of jaguar in a hurry..

The average motorhome gets about 25mpg,

exactly. I was getting sub 20mpg. Ive rented homes before and a diesel
generally does 25-27mpg. This petrol now seems to be somewhere in the
23-25mpg area.

aerodynamics play a lot in this,
especialy if it's a coachbuilt with a standard overhanging luton,
my motorhome got about 27mpg when it was a standard panel van before the
body was built on it, it was totaly empty then as well, now with the
coachbuilt body, all the luxuaries i put in it taking the weight to 4.2
tons in running order (i.e. 140 litres of diesel in the tanks, 150
litres of water, 90 of gas, 70 of red diesel, full fridge, freezer and
larder, all our clothes etc) we now get around 24mpg, which for a 7
meter long coachbuilt isnt too bad,

Indeed.