C vs CP tyres - ride comfort only (1 Viewer)

[roadwarrior]

No, I’m saying they are not meant to flex much in normal operation at the recommended pressures, therefore reducing the pressures puts more flex into the side wall than they are designed for and the rigid construction of the side wall can’t cope, resulting in cracking.

Ok thank you, this is my second set on two differant vans i hasten to add... and never seen any cracking, cracking DOES occur on these tyres as they get old because on all vehicles except motorhomes or campervans that do more mileage and simply wear out before any cracking would occur. There is an advisory that suggests changing after 7 years, but not sure its compulsary, i have even heard of people keeping them for 10 years, by which time the mot man has usually called a halt as they do crack as you say. I would like to see a max of 5 years on the mot but im sure folk would complain, until maybe shown a video of one going bang. But i have not seen any sign of cracking of a young tyre due to under inflation, although of course driving one on say 20 psi would do the trick !

 

[Gellyneck]

Ok thank you, this is my second set on two differant vans i hasten to add... and never seen any cracking, cracking DOES occur on these tyres as they get old because on all vehicles except motorhomes or campervans that do more mileage and simply wear out before any cracking would occur. There is an advisory that suggests changing after 7 years, but not sure its compulsary, i have even heard of people keeping them for 10 years, by which time the mot man has usually called a halt as they do crack as you say. I would like to see a max of 5 years on the mot but im sure folk would complain, until maybe shown a video of one going bang. But i have not seen any sign of cracking of a young tyre due to under inflation, although of course driving one on say 20 psi would do the trick !

Our MoT man passed our 11 year old tyres without comment despite me asking for 3/4 years on their condition.
Simple response was you've looked after them by having them properly inflated however eventually gave up and replaced them!

 

[dunnah01]

, Why would tyre manufacturer possibly say 80psi is perfect on all vehicles in all circumstances -that would be illogical would it not ?.

You'd need to ask ETRTO who advise using 80 psi on the rear axle and following the manufacturer’s advice on the front axle. Michelin follow this advice but other manufacturers ignore it

 

[roadwarrior]

You'd need to ask ETRTO who advise using 80 psi on the rear axle and following the manufacturer’s advice on the front axle. Michelin follow this advice but other manufacturers ignorew itw

why am i not surprised, it really is a black hole of confusion, my personal feeling is its a corporate stance so as not to find themselves in a court of law having made a statement .

 

[roadwarrior]

we know we can email a manufacturer and give our respective weights and get a hard answer, but how does that weigh in with old bill who looks at the plate on the van and say's it should be that not what you said..

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[roadwarrior]

Our MoT man passed our 11 year old tyres without comment despite me asking for 3/4 years on their condition.
Simple response was you've looked after them by having them properly inflated however eventually gave up and replaced them!

as i said no actual law - just advisory, again something to fall foul of when a faction has a differant agender ( like insurance not wanting to pay out
) but look, we all have differant ideas on this and we are all still alive, and have not reshaped our beloved vans - lets hope it stays that way - we dont need any more eu regulations thanks i prefer common sense over laws - remember common sense ??

 

[maison]

we know we can email a manufacturer and give our respective weights and get a hard answer, but how does that weigh in with old bill who looks at the plate on the van and say's it should be that not what you said..

I printed off Falken’s tyre pressure v axle weight chart and carry it in the motorhome together with the Insurance cover note and the V5 when travelling in Europe.

 

[Dorwyn]

So, can you put a 225 on a 215 rim? I noticed that my car tyres are wider and generally beefier than my MH CP tyres, which seems ridiculous. Not in France of course, where they're not so bad. I did change to Michelin all weathers from Michelin CPs on the front of my last van was very pleased. My present Conties are awful too. But they've only done 12k. I can't bring myself to trash them. They're very flat on the top, which seems to suggest that they're over inflated.

 

[dunnah01]

So, can you put a 225 on a 215 rim?

Depends on the wheel rim
width but you're probably OK.

 

[Barriesimpson]

Having read through this thread, I ask myself, if the manufacturer of the vehicle puts a plate on the front door inside frame giving the tyre pressures to be used, are these not the correct pressures for the tyres on said vehicle? On my Jaguar, there are 2 options - light load (i.e. me and the missus) 2.3 bar, heavy load (couple of grandchildren in the back and maybe a few crates of wine in the boot) 2.5 bar. I always run on 2.3 bar as it is normally just me in the car and the ride is perfect. So I follow what the plate says. I have just bought the van and still do not have sufficient experience to change anything so run with what the manufacturer suggests. Am I wrong?

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[Dorwyn]

Depends on the wheel rim
width but you're probably OK.

View attachment 922702

It's that "probably" bit that's the worry!

 

[dunnah01]

Having read through this thread, I ask myself, if the manufacturer of the vehicle puts a plate on the front door inside frame giving the tyre pressures to be used, are these not the correct pressures for the tyres on said vehicle? On my Jaguar, there are 2 options - light load (i.e. me and the missus) 2.3 bar, heavy load (couple of grandchildren in the back and maybe a few crates of wine in the boot) 2.5 bar. I always run on 2.3 bar as it is normally just me in the car and the ride is perfect. So I follow what the plate says. I have just bought the van and still do not have sufficient experience to change anything so run with what the manufacturer suggests. Am I wrong?

You're absolutely right but you may find it very crashy on UK potholed roads and wish to find a safe way to run at lower pressures to soften things up a but

 

[dunnah01]

It's that "probably" bit that's the worry!

I meant that the rim width needs to be checked but very likely to be between 6.5 and 8.5 inches

 

[Hettie's Crew]

So, can you put a 225 on a 215 rim?

Your rim size is likely to be 7J, though check. We went from 215/70 15 to 225/70 15 on our 7J alloys on the advice of SV Tech to increase axle weight. No problems at all and the tyre fitter confirmed a 7J rim was appropriate for the 225/70’s

 

[Dorwyn]

You're absolutely right but you may find it very crashy on UK potholed roads and wish to find a safe way to run at lower pressures to soften things up a but

How have we got to this?:We fancy ourselves as a world leading country but in reality ...

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[Barriesimpson]

You're absolutely right but you may find it very crashy on UK potholed roads and wish to find a safe way to run at lower pressures to soften things up a but

Well I'm not on UK roads but will be travelling up to Northern Ireland at the end of August, so we'll see. Having said that, did you ever see the state of the Canarian roads?

 

[Dorwyn]

In the sixties I put some wider rims on a 50s VW beetle. Road handlng was beautiful, but the lower profile blew the engine presumably due th the higher revs.! That was then, of course

 

[Dorwyn]

Well I'm not on UK roads but will be travelling up to Northern Ireland at the end of August, so we'll see. Having said that, did you ever see the state of the Canarian roads?

What's wrong with loose gravel? At least you know what's beneath

 

[roadwarrior]

Having read through this thread, I ask myself, if the manufacturer of the vehicle puts a plate on the front door inside frame giving the tyre pressures to be used, are these not the correct pressures for the tyres on said vehicle? On my Jaguar, there are 2 options - light load (i.e. me and the missus) 2.3 bar, heavy load (couple of grandchildren in the back and maybe a few crates of wine in the boot) 2.5 bar. I always run on 2.3 bar as it is normally just me in the car and the ride is perfect. So I follow what the plate says. I have just bought the van and still do not have sufficient experience to change anything so run with what the manufacturer suggests. Am I wrong?

My thoughts go like this on your plate. Its a car ..... there is very little capacity to dramatically increase the load maybe by say 40k- while on a motorhome adding 40 kilos is as easy as falling off a bike, i have just increased my load capacity by 400 kilos, if i used that capacity how would that effect the accuracy of a tyre pressure plate based on the factory fitted 3850k van it used to be before and is now 4250k
for instance ?

 

[dunnah01]

My thoughts go like this on your plate. Its a car ..... there is very little capacity to dramatically increase the load maybe by say 40k- while on a motorhome adding 40 kilos is as easy as falling off a bike, i have just increased my load capacity by 400 kilos, if i used that capacity how would that effect the accuracy of a tyre pressure plate based on the factory fitted 3850k van it used to be before and is now 4250k
for instance ?

If it was just a paper exercise up-plate then your max axle loads won't have changed so the tyre pressures would be as the manufacturer's sticker. If you've made changes to the axles to strengthen them, wheels, tyres, air assist etc then you need to find what is the correct pressure based on the new max axle load and the tyre manufacturer's guidance.

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[Hettie's Crew]

Having read through this thread, I ask myself, if the manufacturer of the vehicle puts a plate on the front door inside frame giving the tyre pressures to be used, are these not the correct pressures for the tyres on said vehicle? On my Jaguar, there are 2 options - light load (i.e. me and the missus) 2.3 bar, heavy load (couple of grandchildren in the back and maybe a few crates of wine in the boot) 2.5 bar. I always run on 2.3 bar as it is normally just me in the car and the ride is perfect. So I follow what the plate says. I have just bought the van and still do not have sufficient experience to change anything so run with what the manufacturer suggests. Am I wrong?

The manufacturer that puts the label in the door side is Fiat, Mercedes, Ford, PSA, etc when they produce the basic cab that goes onto the Motorhome coach builder, they could put anything on there varying by a few tons and hundreds of kilograms per axle.

 

[peterc10]

we know we can email a manufacturer and give our respective weights and get a hard answer, but how does that weigh in with old bill who looks at the plate on the van and say's it should be that not what you said..

We do not have a plate showing tyre pressures on our Hymer. Just carry a copy of the tyre makers recommendations, which vary depending upon axle load.

 

[cyberyacht]

You're absolutely right but you may find it very crashy on UK potholed roads and wish to find a safe way to run at lower pressures to soften things up a but

Anything harder than a bouncy castle is likely to feel 'crashy' on UK roads.

 

[a900ss]

Just to close this thread, I had the Falkens fitted today.

I did have Continental CP tyres and replaced with same size/load/pressures. The Contis were only a year old so hadn’t hardened with age.

The difference in ride is stark based on 100 miles today.

It was never going to be a magic carpet ride but the wincing I make when having to drive over a pothole has gone.

It’s just dampened down all the previous harshness.

Well worth the change and I would thoroughly recommend the Falkens (AllSeason 11) for ride comfort. Too early to comment on grip/wear/MPG.

Thanks all for contributing.