Tyre Pressures, reply from Continental Tyres

[marjohn]

Not the same van, quite a small one, the book says 5 bar and that's what we use. So I agree, that does look low. We have a sticker in the door frame and I take that as a legal requirement.

Go to a garage for court and look at the tyre pressures on the charts or go to a tyre supplier

 

[Chockswahay]

I have also emailed Continental in respect of my Ducato 4005kg chassis van, on which I have Fourseasons 2
225/75 R16's fitted. I will be interested if it compares to the Fiat handbook recommendations...

That's the problem, Fiat are simply 'covering their arse' to cater for stupid builders and the like! The pressures for my van are way in excess of the pressures recommended by Continental.

I'm sticking with the tyre maker, after all, they make the tyres!

 

[Chockswahay]

I have just had a look at some 'figures' regarding my van (Fiat 2013 130 Globecar)

On a ferry to the Hebrides in 2013 I had the axle weights measured by the ferryman (for free) The van was in full touring trim, near full diesel, 70 litres of water and 30 litres of gas. Me and my Mrs were sat in the front during the weigh in....

Front 1590 kg

Rear 1320 kg

Based on these weights Continental recommend 51 psi front and 47 psi rear

For normal use I (currently) use the following weights:

Front 1705 kg ...... 55 psi

Rear 1516 kg ...... 55 psi

This keeps it nice and simple (for me) and provides a degree of latitude each side of these weights.

As I have stated before, the tyre makers are the ones who should know best what pressure suits their tyres. At these pressures the ride is quiet and comfortable, the tread is wearing uniformly, the tyres do not get hot, the mpg is as I expect it to be, and my fillings stay in place. I think there are too many vans out there running too high tyre pressures

I dunno if this posting helps anyone but I thought I'd put it here just in case

EDIT: as some eagle eyed Funsters may have noticed I have ran my tyres between 50 and 60 at various times My point is these are far removed from the 78 and 80 that Fiat suggest!

 

[Techno]

It's not rocket science to calculate.
A tyres max load rating is proportional to it's maximum inflation pressure. The size of the tyre is irellevant in the equation.
If a particular Michelin has a load rating of 1250kg at 80 psi then reducing the load allows lower pressure.
The spread sheet I procured from "I can't recall" facilitates this.
It appears to me that the OP's original figures are based on a 68psi max pressure on the tyre wall, whether that is intended for the USA isn't relevant but I believe it is in calculating the proportion of air to the amount of load.

As for contacting tyre manufacturers, this is good with the exception that Michelin will quote maximum pressure for the rear tyres regardless of the axle load you give them. 80 psi

 

[Chockswahay]

It's not rocket science to calculate.

Agreed. I think what causes confusion and concern for many people is that Fiat state 78 and 80 regardless of weight being carried........ a lot of people blindly do as Fiat tell 'em

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[Techno]

Agreed. I think what causes confusion and concern for many people is that Fiat state 78 and 80 regardless of weight being carried........ a lot of people blindly do as Fiat tell 'em

Even more confusion when someone changed the original equipment tyre for some or other cost saver

 

[Pat and Trish]

It's not rocket science to calculate.A tyres max load rating is proportional to it's maximum inflation pressure.

Maybe not for you Andy but I am struggling

I have a Fiat Ducato 2.3 Autotrail Apache 634 motor caravan with factory fitted Continental Vanco Camper 215 70 R15 tyres.
The max axle weights are 1850 kgs front and 2000 kgs rear.
According to the chart that indicates to me pressures around Front 60psi Rear 78 psi, would you agree and like a previous poster the tyres advise max 69 psi.

Any help greatly appreciated
Pat

 

[Techno]

Maybe not for you Andy but I am struggling

I have a Fiat Ducato 2.3 Autotrail Apache 634 motor caravan with factory fitted Continental Vanco Camper 215 70 R15 tyres.
The max axle weights are 1850 kgs front and 2000 kgs rear.
According to the chart that indicates to me pressures around Front 60psi Rear 78 psi, would you agree and like a previous poster the tyres advise max 69 psi.

Any help greatly appreciated
Pat

I need to know the load rating of the tyre as stated on the tyre wall
The actual weight of each axle loaded

 

[Techno]

I believe your tyre loading is 109
going by your maximum axle weights...............the spreadsheet says
However your best course of action is to email Continental

 

[JeanLuc]

Have you downloaded the Conti data book? I put a link to it on the previous page of this thread. That gives the following information for Conti Vanco Camper (CP) tyres of size 215 70 R15 CP.

Load index 109 used singly - (109 x 1.85 used in twin formation)
Pressures (single formation)
Front axle
Load 1,795 kg - Pressure 4.0 bar
Load 1,885 kg - Pressure 4.25 bar
Rear axle
Load 1,985 kg - Pressure 5.25 bar
Load 2,060 kg - Pressure 5.5 bar

Your stated maximum pressures fall between the values given in the data book - hence I have provided two sets bracketing them.
So a fair mean value for you would be:
Front 4.2 bar = 61 psi
Rear 5.4 bar = 79 psi

Allowing for my rounding, these are the same pressures that you have already found in a chart.

Note that Conti specify high pressure valves with these tyres, not standard car and light van tyres.
Specifically TR 600 XHP on the front and TR 602 HP on the rear.

Two thoughts: How close to the maximum axle weights do you actually run? Most people seem to find they run lower than this. If in any doubt, contact Continental's technical department - they are very helpful.

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[Pat and Trish]

Thank you both for your thoughts, I will email conti and also load up and visit weighbridge and see where that leads me.

 

[SMB]

Here is the relevant extract from the Conti Technical data book (downloadable from their website.). You will note that the reply from them accords with the data book. Look at the CP line in the lower section of the image and read across; FA and RA refer to front and rear axle - the S is for single tyres as opposed to twins.

Hope this helps.


View attachment 54146

View attachment 54146

Thanks Philip, your explanation and the manual download has helped a lot, it appears I should be running with 4.0 bar on the front and 4.5 bar on the rear contrary to Fiats recommendation of 5.2 bar front and rear! I will adjust the pressures tomorrow and see how the van handles when I move on next week..