Weighbridge and tyre pressures reality

[U.Toadifact]

Our Rienza is rear wheel drive Transit base. I really need to ind a weigh bridge if only as a matter of interest. The garage that services it checks and adjust the tyre pressures to 50 psi fronts and 60 psi rears. Being leaf springs at the back it’s a fairly hard ride any way but the Conti Campers seem ok handling wise and have worn well.
I am not sure we’re to find a weigh bridge here. Maybe the VOSA test station. I will look into this.

JHP Storage Ltd on the Elsham Wold Industrial Estate DN20 0NX is where I use. The operator is very helpful and friendly and it is £9.60 a pop.

 

[ontheroadagain]

I'm running at 51F/70R psi based upon Continental's sound recommendations

Following a visit to a weighbridge and excellent advise from Continental, I have been running our Elddis at the exact same pressures for the last two years. Fortunately, I also found a Peugeot dealer who was able/willing to reset the TPMS.

 

[Hettie's Crew]

I recently used the dynamic scale weighbridge at King George Dock in Hull with the following results:

Front 1810. (Plated at 1850)

Rear 1550. (Plated at 2000)

Gross 3360. (Plated at 3500)

This was in holiday trim with 2 adults included (for a week), ie. full fuel tank, full fresh water, full lpg underslung, empty grey waste, empty cassette. We don’t carry bikes or bbq but do have mountain walking gear and then general clothing and food of course! etc.

Contacted Continental Tyres for their recommended tyre pressures

Front 3.5 bar (50psi), Rear 3 bar (45psi)

This made for a really comfortable ride compared with the factory set up of 60psi all round.

Vantage Sol PVC 6m

Derek

http://blobs.continental-tires.com/www8/servlet/blob/85806/69977261017e17f2a1dc8054655a4bcf/download-technical-databook-data.pdf

 

[Don Campbell]

Do you have Michelin’s? no matter what you weigh in on the axles, they always say 80 psi.. rock hard ride.

I have my fronts at 64psi and rears at 72psi, better but not brilliant

It's worth having a look at the Michelin USA site for tyre pressure recommendations https://www.michelinrvtires.com/reference-materials/load-and-inflation-tables/#/

 

[Rumour and Innuendo]

I recently used the dynamic scale weighbridge at King George Dock in Hull with the following results:

Front 1810. (Plated at 1850)

Rear 1550. (Plated at 2000)

Gross 3360. (Plated at 3500)

This was in holiday trim with 2 adults included (for a week), ie. full fuel tank, full fresh water, full lpg underslung, empty grey waste, empty cassette. We don’t carry bikes or bbq but do have mountain walking gear and then general clothing and food of course! etc.

Contacted Continental Tyres for their recommended tyre pressures

Front 3.5 bar (50psi), Rear 3 bar (45psi)

This made for a really comfortable ride compared with the factory set up of 60psi all round.

Vantage Sol PVC 6m

Derek

Proper job! It is what everyone should do and get the actual correct pressures and not just guess, take advice from Facebook tyre experts or follow the van plate! We found just about the same as you. instead of the van converters 65 in the front and 60 in the rear! We now run at the same as you on our 14" wheels.

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[ChesterB]

I am a little concerned at the large discrepancy in tyre pressures some of those posting seem to consider acceptable, apparently on the basis that it "feels more comfortable"
If you reduce a tyres pressure from 70+psi to 50 ish, then the likely effect is to introduce much more of the tyre surface to the road, this in turn requiring the tyre to flex/alter shape far more than it would at higher pressure.
The inevitable consequence of any such action is a significant increase in the tyre's temperature and all the problems that this leads to.
As someone mentioned, the difference between a delivery van on a (Fiat ducato) chassis & a motorhome is that the delivery van probably only spends a small percentage of it's time loaded to the maximum permitted.
Given the propensity of motorhomes to flip following tyre blowouts, I think it requires a lot of careful research before tinkering with tyre pressures.
Offering up the "it felt more comfortable" explanation to a Coroner is not a course of action I would recommend.
CB.

 

[Hettie's Crew]

I am a little concerned at the large discrepancy in tyre pressures some of those posting seem to consider acceptable, apparently on the basis that it "feels more comfortable"
If you reduce a tyres pressure from 70+psi to 50 ish, then the likely effect is to introduce much more of the tyre surface to the road, this in turn requiring the tyre to flex/alter shape far more than it would at higher pressure.
The inevitable consequence of any such action is a significant increase in the tyre's temperature and all the problems that this leads to.
As someone mentioned, the difference between a delivery van on a (Fiat ducato) chassis & a motorhome is that the delivery van probably only spends a small percentage of it's time loaded to the maximum permitted.
Given the propensity of motorhomes to flip following tyre blowouts, I think it requires a lot of careful research before tinkering with tyre pressures.
Offering up the "it felt more comfortable" explanation to a Coroner is not a course of action I would recommend.
CB.

I don’t see anyone just reducing them ‘for’ comfort. They have, as have we, reduced their pressures following tyre manufacture recommendations.
This of course isn’t possible if you choose or are stuck with Michelin CP tyres.
Personally, if I had Michelin CP’s I would run them at Michelin’s recommendation until I got rid of them.

 

[Woodgates]

I am a little concerned at the large discrepancy in tyre pressures some of those posting seem to consider acceptable, apparently on the basis that it "feels more comfortable"
If you reduce a tyres pressure from 70+psi to 50 ish, then the likely effect is to introduce much more of the tyre surface to the road, this in turn requiring the tyre to flex/alter shape far more than it would at higher pressure.
The inevitable consequence of any such action is a significant increase in the tyre's temperature and all the problems that this leads to.
As someone mentioned, the difference between a delivery van on a (Fiat ducato) chassis & a motorhome is that the delivery van probably only spends a small percentage of it's time loaded to the maximum permitted.
Given the propensity of motorhomes to flip following tyre blowouts, I think it requires a lot of careful research before tinkering with tyre pressures.
Offering up the "it felt more comfortable" explanation to a Coroner is not a course of action I would recommend.
CB.

My comment about comfort follows a recommendation from the tyre manufacturer relating to actual axle weights. I didn’t just reduce or tinker with pressures for comfort as you seem to be implying, apparently.

 

[ChesterB]

Yes Woodgates, I wasn't so much commenting on your actions as those of at least two others who added remarks which suggested
they had not thought through the possible consequences of their actions.
It is quite reasonable to expect a tyre company that produces tyres specifically for motorhomes to list pressures for individual makes & maybe even models of those motorhomes - but if you fit a tyre that is certainly quite up to the job, but is not specific to your motorhome, then you need to pay close attention to what the motorhome manufacturer specifies, not the tyre manufacturer.
I agree that the usual EU belt & braces approach may be rather a blunt tool, but it is there to avoid this problem.
Either way, the main point point, which I have not seen anyone refer to yet, is that you should be constantly monitoring your tyres during longer journeys, specifically for signs of excessive heat, but also just to see if they look right. Unless tyres are old or badly worn, they seldom go bang in an instant, short of a direct hit on something.
CB

 

[Jamesh]

But you may also consider the fact that tyre manufacturers have to give greater pressures for MH because the majority spend 48 weeks if the year sat stationary. Hence the high pressures and the stiff sidewalls.

If however your a regular user a standard van tyre and pressure may suffice.

I cannot see the use of a motorhome being any more arduous than a supermarket / multidrop delivery van or a utilities van towing a 3.5t trailer....

Just a thought.

Cheers James

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[Don Campbell]

I think I would tend to trust the tyre manufacturers rather than the motorhome builders and if the tyre manufacturers recommendations were not accepted in a Coroners Court (God forbid that should ever be the case), it could also be argued that the manufacturers recommendations were a case of over inflation and contrary to the recommendations by the tyre manufacturers which on a long run on a hot day might well result in a blow out. Which do you prefer - I know whose advice I'm taking.

 

[3crispies]

Just reading with interest, we are booked into a weighbridge this week and are looking into tyre pressure too. We have Michelin CP tyres and since we had mh in the summer always stuck to 79psi. Ride is awful and as previous had contact through local tyre dealer to recommend tyre pressure with Michelin. We have purchased a spare wheel and tyre dealer are sourcing a tyre. Obviously we have to match Michelin CP but how can we correct pressure/weight for front and rear.
We use mh regular so can we drop pressure to suit.
Ours is 2022 ducato and assuming tpms works have never seen warning light....

 

[Hettie's Crew]

Just reading with interest, we are booked into a weighbridge this week and are looking into tyre pressure too. We have Michelin CP tyres and since we had mh in the summer always stuck to 79psi. Ride is awful and as previous had contact through local tyre dealer to recommend tyre pressure with Michelin. We have purchased a spare wheel and tyre dealer are sourcing a tyre. Obviously we have to match Michelin CP but how can we correct pressure/weight for front and rear.
We use mh regular so can we drop pressure to suit.
Ours is 2022 ducato and assuming tpms works have never seen warning light....

Michelin CP’s are designed to run those high pressures to keep the walls stiff. If you reduce the pressure you increase the side wall flex which will end up cracking.
See my comment in post #37.
My advice is bite the bullet financially and get rid, or put up with them.

 

[Folkranger]

I recently used the dynamic scale weighbridge at King George Dock in Hull with the following results:

Front 1810. (Plated at 1850)

Rear 1550. (Plated at 2000)

Gross 3360. (Plated at 3500)

This was in holiday trim with 2 adults included (for a week), ie. full fuel tank, full fresh water, full lpg underslung, empty grey waste, empty cassette. We don’t carry bikes or bbq but do have mountain walking gear and then general clothing and food of course! etc.

Contacted Continental Tyres for their recommended tyre pressures

Front 3.5 bar (50psi), Rear 3 bar (45psi)

This made for a really comfortable ride compared with the factory set up of 60psi all round.

Vantage Sol PVC 6m

Derek

I've always considered the continental tyre pressures guide. All the rest are just covering their ar**s.

 

[Don Campbell]

Just reading with interest, we are booked into a weighbridge this week and are looking into tyre pressure too. We have Michelin CP tyres and since we had mh in the summer always stuck to 79psi. Ride is awful and as previous had contact through local tyre dealer to recommend tyre pressure with Michelin. We have purchased a spare wheel and tyre dealer are sourcing a tyre. Obviously we have to match Michelin CP but how can we correct pressure/weight for front and rear.
We use mh regular so can we drop pressure to suit.
Ours is 2022 ducato and assuming tpms works have never seen warning light....

When we had Michelins we were told to use a high pressure but as you say the ride is terrible. Michelin US site has a RV pressure chart and it's https://www.rvsafety.com/images/pdf/michelinloadandinflationrvtruck.pdf . I seem to remember we used pressures in rge mid 50's but ideally you need the weighbridge axle weights.

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[Carpmart]

I run at (cold) 82 psi rear (four tyres) and 70 psi front. Ride is what it is really, it's a commercial vehicle. Air sprung seats helps a lot! Feel sorry for the dog occasionally!

 

[Don Campbell]

I run at (cold) 82 psi rear (four tyres) and 70 psi front. Ride is what it is really, it's a commercial vehicle. Air sprung seats helps a lot! Feel sorry for the dog occasionally!

It's a big beast but with duals it does seem very high. You'll have to buy the dog an air seat and I feel sorry for the joinery.

 

[Lenny HB]

It's a big beast but with duals it does seem very high. You'll have to buy the dog an air seat and I feel sorry for the joinery.

Our daughter's dog used to love our last van, one ride in this one & she refused to get in again. Once we fitted full air she was OK with it.

 

[Hettie's Crew]

When we had Michelins we were told to use a high pressure but as you say the ride is terrible. Michelin US site has a RV pressure chart and it's https://www.rvsafety.com/images/pdf/michelinloadandinflationrvtruck.pdf . I seem to remember we used pressures in rge mid 50's but ideally you need the weighbridge axle weights.

That’s probably because the US doesn’t accept the EU CP rating that we have to put up with. The chart relates to Michelin Agilis etc but states LRC (Load Range C) not CP.

 

[Lenny HB]

That’s probably because the US doesn’t accept the EU CP rating that we have to put up with. The chart relates to Michelin Agilis etc but states LRC (Load Range C) not CP.

CP tyres are only made in very limited sizes none suitable for an RV or bigger European Motorhomes you will find them all shod with C tryes.

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[Hettie's Crew]

CP tyres are only made in very limited sizes none suitable for an RV or bigger European Motorhomes you will find them all shod with C tryes.

Yes! I know.

 

[Don Campbell]

Apparently motorhomes got stuck with CP tyres because we can't be trusted not to overload our vehicles, but as Lenny says the choice is limited in the right sizes and Michelin does say their Agilis tyres are OK for motorhomes. Anyone ever been prosecuted for fitting C tyres? Bet not!