Nuevo tyre pressures (again)

Hi Folks,
At the risk of opening old wounds (I know this topic is an old favourite), I would appreciate any thoughts, suggestions and advice please.

Our Nuevo is a 2005 ES with plated limits of 3400 overall with front axle max of 1750 and rear axle of 1900. We had her weighed recently in (almost) 'holiday' load mode and this produced figures of 3180/1460/1920 in the same order as above. Some juggling of the load got the rear axle below 1900 (just). I emailed the tyre manufacturer but have had no response hence my appeal for advice.

The tyres are Yokohama Deliverystar 215/70R15c. We decided to have the rear suspension upgraded so have had Dunlop air suspension fitted which at least puts some curve back into the rear springs. The van now rides much better but seems to have lightened the steering a fair bit. This was a bit of a surprise as I imagined that with the back 'jacked up' a bit more weight would be put forward to the front but the steering is appreciably lighter causing some 'wandering'.

So here we have the  problem of what pressures to use now. Pre air they were 57 rear and 50 front. Air is inflated to 25psi. Any thoughts and/or suggestions would be appreciated particularly from owners who may have the same set up. Many thanks in anticipation.
Barry

Barry,
It doesn't matter what pressure you put into your air system the weight on each axle will remain the same - hence, the tyre pressures will remain the same.
You would have to get a significant incline on your van to get any appreciable transfer of weight forward.

That rear load looks a bit dicey - I would try unloading that extra kitchen sink

Derek

In the past I have used this table to help work out what I thought the optimum for my vehicle. Like you I first made sure the van was in holiday load.

http://3w3cym44fnwj2kigcp2sxvg8.wpengine.netdna-cdn.com/wp-content/uploads/2015/12/motorhome-leaflet.pdf

Hope this helps or at least progresses your query.

Davy

The Tyresafe guide and a Continental Tyres guide are in the Fact sheets section.

Thank you both. Perhaps I am really dense or missing something, but I don't really understand the chart. Please don't 'tut' a thicko but with the info I have given, could you please translate this into something I would understand?  Sorry!!!

My Nuevo ES has the same plate and we had it weighed at a show and we had over 300kg still available with a weekends load on board so I don't know what extra weight you are carrying. From your tyre size I presume you have camper Tyres, same as mine and using the maximum weights off your plate your pressures should be 65 and 70 
As I said we weigh much less than yours and I run with 55 and 60psi. Are you sure of the weight,  and are you using a council weighbridge?

The data for your tyre is incomplete. There should be other reference numbers, probably 109R which is the load rating (109) and speed rating (R) R is 106mph. They are commercial tyres (C) not camper (CP), so in the table look up in the top list your tye size (it isn't shown though) but for 225 @109 load rate, for 1460 front pressure is 36 psi, and for 1900 rear pressure is 50 psi.


http://www.mytyres.co.uk/cgi-bin/rshop.pl?dsco=110&cart_id=39791722.110.7438&Breite=215&Quer=70&Felge=15&Speed=&kategorie=0&ranzahl=4&Transport=P&tyre_for=LLKW&x_tyre_for=&Ang_pro_Seite=50&sort_by=Lable_2nass&rsmFahrzeugart=PKW&filter_preis_bis=&filter_preis_von=&Label=F-B-74-3&details=Ordern&typ=R-129914&active_tab=1

Thanks again guys. Replying to Poughlin first - I agree that My Deliverystars are commercial rather than specific 'camper' tyres. They are rated 109 as you surmise. Your suggested pressures look a bit more realistic to me but without experience I am groping in the dark a bit and relying on others' advice. Thanks you for it.

Now to Paul: As above, my tyres seem to be bog-standard commercial tyres BUT I am loathe to use the figures on the cab as my guess is that Sevil supply chassis cabs not knowing what will be fitted to the back. Again, I am loathe to use a pressure of 70 or even 65 as the side of my tyres clearly states that the maximum inflation pressure is 65. The weighbridge was not 'council'. We don't have them in the South east. I used Hansons the national aggregate and ballast suppliers who have recently opened a new depot nearby. Their weighbridge is massive as they need to weigh lorries up to 40 tonnes. They are visited by trading standards officers every month so I am confident that their weighbridge is 100% accurate. if yours was weighed at a show, I would guess that this was a portable type? As to weight carried, we do have a Fiamma back box on a bike rack but only carry 'lights' in there. Screen cover, 2 ramps and an empty water carrier. In all 49kg, Van also has a tow bar.

Yes you are right, it was weighed on portable scales but by SVTech the people who are expert in uprating vehicles (obviously they told me I didn't need uprating). I will pop over to our local weighbridge out of curiosity and get weighed again.

Be interested to see your result!

Been to local weighbridge today (Council) and in pretty much holiday mode these are my results.
Front axle 1345kg   -  Rear axle  1560kg  - Total weight  2905kg.  

This is with me and the wife, half tank fuel, 10galls fresh water, clothes, food & drink (allowance made for those as we had emptied those).  So your weights seem excessive by comparison.

That's interesting Paul. My only 'extras' at the back are the tow bar (around 50kg I would guess) and the Fiamma box which I have weighed to 49kg. Can't account for any other significant differences as yours looks like a 4 berth as is ours. Have settled for 40psi front and 55 rear for time being as after fitting of the air suspension the steering seems much lighter which makes no sense at to me.

When I first had my Nuevo, when Charles was at AS, he gave me 55 front and 60 rear for my Michelin camper tyres, So I have always run to these pressures. I have always kept Michelins on the van. It takes a while to get these tyres, so you have to think in advance when you want to change them. I always needed to check the pressures after service as they would always inflate to 70 psi, I now tell them before the service the pressures I want.

My vehicle went for its MOT last week.  It was fairly empty though it had al the china in the back cupboards over the sink and pots and pans under the cooker - plus 75% fresh water which Willersey had put in as part of their habitation service.
Axle waights were Front 1250kg, Rear 1650kg.  Max weights on my 3500kg MGW are Front 1850, Rear 2000kg.  Tyres are Continental 215/70 R15 CP 109 R
Plate inside passenger door specifies 5 bar Front (72psi) and 5.5 bar Rear (80psi) which are absurdly high especially as tyre wall suggests 69psi max.
I don't take the van up to the full 3500kg but if I di I would hazard a guess that axle weights might be 1600kg Front and 1900kg Rear.
Using the Continental pressure chart in our Fact Sheets suggests 3.5 bar Front and 5 bar rear.  But 4,5 bar on the rear would allow 1750kg there which is probably ample for me. At the same time I would put the fronts up to 3.75 bar.
In old money those are 55psi front and 65psi rear which is in the same ball park as others on this and similar threads. 
Like others, I find that the garage puts them up to 75psi!

inspiredron wrote:
I don't take the van up to the full 3500kg but if I di I would hazard a guess that axle weights might be 1600kg Front and 1900kg Rear.

Surely the axle weights stay the same no matter what tyre pressure you run at? 

Conversely, the tyre pressures can be adjusted dependent on the axle weights involved.

Ah! That makes sense now. Thanks C.

Gents, I started this thread so many thanks for all the useful advice offered. Since posting we have just completed a 1500 mile round trip to and around Scotland and ran the van at 45psi front and 55 rear, The Dunlop air suspension was set to 25psi. With 3 on board we were close to the 3400kg max weight. The van drove perfectly and was very happy cruising at 60mph on motorways.
We had noticed some lightness of the steering with 50 psi front so reduced to 45 which bizarrely cured this (?). Will stick to these pressures now.

Recently brought a new nuevo with the wonderful tyre under inflation device but has anyone found how to find what pressure they are set at?
Gef

Hi cymru I understand for £60 you can have them switched off!