Tyre Pressures

[Markd]

Apparently 'Euro Advice' is that Camper rear tyres should be at 5.5 bar to allow for 'overloading' - which is what we get from Michelin if we ask.
We've been told that Continental will give specific pressures if asked.
They obviously trust end users to act responsibly if given information.
The Continental Tyre Handbook, along with data on every tyre they make, does give Pressure for Load on various Ply Ratings - so we can save a call and look it up for ourselves.
The loadings start on page 84 but rather than just copy some here's the whole thing to give context I've messed about with original to get Loads on same page so front cover is missing for purists but thi si 2019-20 data.

 

[molly 2]

Just to save some confusion your first line could be misunderstood is it is only cp tyres that are 5.5

 

[Markd]

Yes - that is the European Tyre & Rim Technical Organisation advice for CP rear tyres on Motorhomes.
Of course loads () of us don't bother with CP tyres and this thread wasn't intended to restart that argument but to give owners a chance to see some 'official' pressures for given axle loads, Ply Ratings,Load Index and speed ratings.
Which is complicated enough I think

 

[Markd]

And technically of course only applicable to Continental tyres - another can of worms?

 

[Phantom]

I used an online calc based on my tyre spec and load to arrive at the 65psi I use for my Conti rear tyres. The table suggests a max of almost 69psi so about right. I would not want to overinflate them to 80psi (5.5bar) though.

 

[Markd]

For those who have already read first post I've reformatted the hand book for easy load reading.
Interestingly this highlights that CP tyres are listed with lower loads for a given pressure on Rear axle compared to front.
Also in 225-75-16 the 10 PR tyre needs higher pressures than 8 PR but ultimately has higher capacity

 

[barge1914]

I can’t quite follow the logic. According to Michelin I can run my front Agilis Campers tyres at 65psi with load of 1800kg. But for rears at 1650 kg must be at 80 psi ‘for stability’.

 

[Markd]

I think that's the advantage of using the Conti tabletop get a load appropriate pressure.

 

[Phantom]

A tyres load capacity can also be dependant upon road speed. My Conti Vanco (non CP) tyres are dual rated at 112R and 115N showing that at a lower max speed they have greater load capacity. In my case 2430kg per axle up to 87mph.

 

[Markd]

Indeed - so many variables.
The speed rating us based on vehicle maximum wheel for motorhomes will be probably be either M or N (81 or 87 mph)