Tyre pressures Mercedes base vehicle

The Mercedes recommended tyre pressures for my fully laden Autosleeper Malvern, taken from the plate below the drivers seat are front, 3.7 bar (52psi), rear, 5.2 bar (75psi).
It is fitted with Continental VanCo Four Season 235/65 R16C 119N tyres, and having had a very uncomfortable ride in the 6 months since I have owned the vehicle from new, (with associated rattles), I thought I would speak to Continental about recommended pressures. I got their UK technical centre telephone number from their UK website.
My axle loadings are front, 1660 and rear 2120, keeping me just below the 3850 chassis limit.
Taking those weights into consideration, and with the type of tyre fitted, Continental recommend the following:

Front 3 bar, (43 1/2 psi), rear 4 bar, (58 psi). I am running mine now at front 46psi, rear 58psi.

Aaaaahhhhhh, peace at last, and I do not notice any difference in the handling of the vehicle.
I have updated my tyre pressure plate to reflect those recommendations, just in case they are ever queried.
The Continental technician did say that they are forever getting such queries, and that in almost every case the vehicle manufactures recommended tyre pressures are well in excess of their recommendations.

Thanks for this, I think I'll try the same and report back next time we use it. I seem to remember ours were set at the values given by Continental when we collected ours from the dealer but I changed them to match the plate like you had (generally 50 and 70). I even bought a mains inflator to be able to do it quicker.

A conundrum.

I would have gone that way but the Mercedes handbook specifically states that Motorhome conversions should use maximum load pressures. If I was advising anyone on this subject I would get the data in writing from the tyre manufacturers and send it to my insurers.

With my Peugeot I followed the above procedure with Michelin and got the same result - peace! But both Ford and Mercedes standard documentation forbids it.

I have made a careful note of the pressures you are now using!

Peter

Yes, a conundrum, because at the end of the day its my 'bum' on the seat, so to speak, if it all goes wrong. I take your point about the insurance and will drop them a line. Who knows best, the vehicle manufacturer who I assume has researched the tyre pressures, or the tyre manufacturer who undoubtedly knows the capability of his tyres. I will take the matter up with Mercedes Technical but
will travel in relative silence unless my insurers, or perhaps Mercedes, tell me differently, that's my decision.

This post is for information only and the contents are subjective.

I've set my pressures to F46 R60 and this weekend away done a round trip of 140 miles on mixed roads and speeds whilst fully laden.

The van feels perfectly stable up to legal limits and felt safe and secure at all times. The steering is much heavier and the extra rear suspension provided by the softer rear tires is noticeable and at times uncomfortable.

Shock rattles (hitting a bump) are much the same. Continuous rattles were low anyway but do seem to be less.

I'll be retaining these pressures for a while for further evaluation.

Peter

I met a fellow Autosleepers Mercedes owner this weekend at the Yeovil Steam Fayre. He has possessed his Surrey from new for 3 years. He made the same enquiry of Continental tyres 2 1/2yrs ago, was given the same pressures to run with and reports a much quieter ride with little or no change in ride characteristics.

Just picked up on this thread while searching tyre pressures as mine shakes the hell out of the vehicle set at 75psi in the rear. Cannot do it any good surely?
Will drop them down and see how it goes 

Watch for Merc min pressures. I found lower affected high speed stability and not much diff on rattles. Came back up in stages and finalised on 52 f 70 R. For others, be wary for handling changes when lowering pressures

HI  This talk of tyre pressures comes up constantly.
if you weigh your Motorhome, how you use yours and then use the tyre pressure shown for your tyres and axle loadings in the chart you will be safe.No need to tell your insurance company.
For those figures of 1660 and 2120
I calculate 45 front and 59 rear.
So add a couple for peace of mind if you want.
I agree with your Tyre manufacturer.
regards

Mike

Peter Brown wrote:Watch for Merc min pressures. I found lower affected high speed stability and not much diff on rattles. Came back up in stages and finalised on 52 f 70 R. For others, be wary for handling changes when lowering pressures

That is VERY interesting Peter. I did get caught out on the M1 in that severe gale in January when heading down to Broadway when a severe gust took me right across the adjacent lane. (Fortunately the white van and lorry did the same onto the hard shoulder) Never experienced that before even after driving coaches as well as caravans for many a hundred thousand of miles. The rear tyre pressures were 62 so maybe exacerbated the 'drift'? I think I will go back to 70 as are yours and hope the very hard ride doesn't destroy too much too quickly  

Last year I posted, via Roli, the Continental chart for MH tyre pressures v loading.
I have no idea how any vehicle manufacturer or MH converter can possibly know the loading any of us will have on our vehicles.
The best they can do, therefore, is to give upper and lower weight recommendations.
Tyre manufacturers on the other hand can tell you faily precisely what pressures for THEIR product will produce the optimum performance for a given axel loading.
I must say that when I first got the Continental pressures I was surprised to what degree they were lower than those on the vehicle door plate, but there is a noticeable improvement in performance and comfort using the tyre manufacturers pressures.
I have also since found out that commercial vehicle manufacturers 'plated'  tyre pressures are the maximum pressure for a maximum load.

BTW Jaytee I think you will find that harder tyres will produce more drift if you get hit with a side wind, since you have less friction with the road.

H Backtrax, I think we are in agreement about tyre pressures. They are a compromise.Suspension characteristics including the possibility of worn shock absorbers will alter the handling.
What matters is the contact patch of rubber on the road. If you run with much higher pressures your contact area will be smaller. Could also give you extra wear in the centre of your tread as well.To low a  pressure and your tyres flex too much with increased heat ,the enemy of tyres.
As we all know pressures and damage inspections should be carried out regularly.

best regards

Mike

We run our rear tyres at 65psi, seems to be no issues at that. On the weighbridge fully loaded we were at 3700kgs so well below the 3880kgs max.

I have now settled at 60 rear and 46 front and am happy legally as the Mercedes manual gives min and max pressures depending on tyre type and axle weight not just max weight as per plate.
So for our weights the manual gives 44 empty to 70 laden up to 2250kg rear axle and 44-48 up to 1650 kg front. Not a van so will never be empty weight  
The 75 and 52 are for gross vehicle weight of 4430 kg.

I guess they may have re-written the manual in the last two years but my Mercedes manual says:

Page 294 note 18 "Due to the high net weight of camper vans, the values for fully laden vehicles given in brackets apply."

With my wheels and tyres that's 54 front and 75 rear although after experimentation with ride and rattles I have come down to 52 front and 70 rear.

Peter

Ahhh, just found the statement you mention re motor caravans using the laden weight pressures.   It does give two axle weights though so if I use the axle weight range that applies to mine I need to use 75 rear and 48 front.
However am going to stick with 60 rear as it runs well, don't get hot and fits with my weight in the chart (I can vary upwards as necessary depending on what's aboard) but up the fronts to 48.
Job done  

At last, I think I may have found the answers for my tyres to. I have the same tyres as you but on an Autosleeper Devon on a Merc Sprinter chassis.
I guess they should be about the same weight, or should I get it on a weight  bridge ? While I am here, would you know how to fit the lights adaptors for traveling in Europe ? I have looked at Halford's intructions but they don't make any sense at all.
Kind regards,

Richard

I can only refer you to the factsheet (there are many  - home page, factsheets sub-section)...

https://www.autosleeper-ownersforum.com/t3335-motorhome-tyres

Thanks Paul, I have read the tyre pressure guide you mentioned but unfortunately doesn t seem to have my tyre size of 235, it appears that it only goes to 225. I will try various options as we are off to North Wales tomr for 3 days. Thanks again.
Richard

RICHARD CARBONI wrote:At last, I think I may have found the answers for my tyres to. I have the same tyres as you but on an Autosleeper Devon on a Merc Sprinter chassis.
I guess they should be about the same weight, or should I get it on a weight  bridge ? While I am here, would you know how to fit the lights adaptors for traveling in Europe ? I have looked at Halford's intructions but they don't make any sense at all.
Kind regards,

Richard

Hi Richard,
what I have done with the beam deflectors as I only use black tape is to park pointing at a wall so I can see the beam pattern and put the tape on to stop the raised l/h edge of the beam. You could try the same with your deflectors? Just a thought.
Re tyres, we are off to Iceland week after next and will be at our heaviest so will stick on the weighbridge and set TP's accordingly. 
Good luck John  

I've done circa 1400 miles over the past 4 days at mostly 70 - 80 and am very happy at 52 - 70 fully laden.

Florence at the moment.

Peter

Just ordered a Bourton for October, do they all come with Continental tyres?

Claytaa wrote:Just ordered a Bourton for October, do they all come with Continental tyres?

Seems to be what Mercedes use; certainly at the moment anyway. Good tyres   , use them (AT's) on the Landy as well.

Hi, Thanks Suenbar, now getting confused with tyre details. It seams that I have the same tyres as you. 235/65 R16C, Vanco 2, but where does your
119 N comes from ? all I can see on mine are 115/113 R ! What is this about ? 
Richard