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Round Black And Confusing


dsms

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Time to replace our tyres and getting confused by choices of type and suitability.

Cuerrrently the van (Vanroyce 423 s/sk ULW 825kg) is shod with the old 175R13's 89 load ratings and from markings appear to be Reinforced 6ply's. Checking round at local and on internet tyre suppliers these are to put it mildly 'thin on the ground' (read near impossible to get) and I am being offered 'alternatives'. Either 6 or 8 ply C grades or 86 load rated.

This throws up a few dilemas:

1. which would be the better bet to go for ( see below for confusion connumdrums)

2. in either case what effect would changing have on pressures and what would the new pressure be.

 

The van handbook does not really help, the only reference to tyres at all simply gives a guide pressure of 35psi. A Vanroyce sales leaflet (for later models) is a tad more helpful in showing a tyre spec for various variations of van i. e two year newer 435 2 sk is shown as having 175R/F/13 tyres but at a pressure of 44psi but for a 940 kg ulw version of the van (larger heavier 960 ulw vans going to the C rating at 54 psi) whereas smaller 365/2 similar weight vans (840kg ulw) use 175SR13 tyres which would be the 86 load rated tyres run at 36 psi.

 

Total brain damage at moment

Anyone have any thoughts/guidance on way to go, prices are quite similar at around £100 to £110 fited/balanced/etc.

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The is a technical help leaflet on tyres on the caravan club website but you need to be a member to access it.

 

Brian

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The is a technical help leaflet on tyres on the caravan club website but you need to be a member to access it.

 

Brian

17540[/snapback]

 

 

Have downloaded that read and it simply adds to confusion

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Dsms

 

Have a look here Tyre Loads it might be helpful. You will notice that it gives two load ratings depending on speed. This is important if you intend to travel in France as the tyres must be capable of travelling safely at the highest possible speed (130kms) regardless of whether you intend to go that fast.

 

On my last van when I replaced the tyres I also found them difficult to find. I was also restricted by find a supplier happy to change tyre on wheels with Tyron Safety Bands. I needed 6ply but one dealer said he had 8ply in stock. I was advised against that because the van would feel very stiff on poor roads. Eventually I got 6ply commercial tyres (the C in the description). These were fine and I think cost about £100 for the pair.

 

David

David - Milton Keynes

Bailey Alliance 66-2 Motorhome for holidays and a Kia Venga for home.

 

Caravan Travels

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dsms - you'll need to know the MTPLM or Gross Weight of your caravan, not the MIRO or net weight.

 

The increased load limit for restricted speed tyres SHOULDN'T be used as this only allows 100 kph (62 mph) which is too close to the UK towing limit.

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Guest john1215

On my last van I was lucky to suffer a puncture whilst the van was at the storage yard so no damage done. I had the tyre replaced and the dealer recommended an 8 ply tyre which I had fitted at a cost of £57, I didn't notice any loss of stability on any road though, it just felt normal really.

 

john1215

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dsms - you'll need to know the MTPLM or Gross Weight of your caravan, not the MIRO or net weight.

 

The increased load limit for restricted speed tyres SHOULDN'T be used as this only allows 100 kph (62 mph) which is too close to the UK towing limit.

17565[/snapback]

 

 

what are you saying are 6 & 8ply C grade speed restricted to 62 MPH, this is what your message infers.

In which case what should be used as an alternative. ..175/80/13 86T tyres being the alternative to the C grades have the speed rating but their load limit falls short when you take into account the 90% recommendation.

 

Prime example of the confusion!

 

I have been recommended by a local tyre depot to use 175/80/13 6 ply C grades as according to them these are the ones they generally supply/fit for caravans

 

Getting really lost in the mist now!!

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Dsms

 

I think that was why Roger was asking for the max gross weight of you van. As tyres seem to have two load weights depending on speed I read his reply as making sure you use the lower load rating as the higher one is too near the speed limit in this the UK?

 

David

David - Milton Keynes

Bailey Alliance 66-2 Motorhome for holidays and a Kia Venga for home.

 

Caravan Travels

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Dsms

 

I think that was why Roger was asking for the max gross weight of you van. As tyres seem to have two load weights depending on speed I read his reply as making sure you use the lower load rating as the higher one is too near the speed limit in this the UK?

 

David

17583[/snapback]

 

from the tyre loads chart mentioned above 175 x 13 (6ply) tyres have axle weight/mph quoted as 1407kg @60mph 1340kg @81mph

the lower weight 1340Kg would be far in excess of the max weight for our van @ 825Kg ULW

I would not in my wildest dreams imagine an allowance to be anywhere close to 515Kg to bring total weight to the 1340 figure. ..our handbook nor plate actuall shows a MLW just an ULW of 825 based on the later sales brochure we have always kept a load allowance down to around 150 Kg max which is the lowest quoted in the booklet (for a smaller van) the same model but heavier van as ours is shown as having a 254kg allowance but we prefer to play safe!

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Thanks, David (Klyne), fo explaining my points.

 

Tyre suppliers can only advise if they know the gross weight that will be used. I understand dsms's predicament if the rating plate is missing but underlines the need NEVER to buy a caravan with missing or tampered rating plate - it indicates fraud or theft.

 

R/F, 6-ply, 8-ply and C tyres are rare now in 13" sizes as caravans and commercial vehicles have long since moved up to 14" or 15".

 

Kumho make a 165 C13 which is rated as 94N which would suit an MTPLM up to 1340 kg. These use a tyre pressure of 65 psi at max load, but this can be reduced proportionately for lower loadings.

 

My 2001 Pageant has these tyres, the last year before 14" became standard. Bailey recommend 54 psi at the Pageant's 1218 kg MTPLM. They ride very smoothly, once they were balanced.

 

Check your local tyre suppliers. They'll almost certainly have to order and will probably need time just to quote a price.

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The reason caravan manufacturers have changed to 14" wheels is the lack of other vehicles using 13" wheels and therefore the general lack of tyres. As time goes on and the number of caravans with 13" wheels reduces, the shortage problem will get worse.

 

Brian

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As far as I'm aware the Escort van was the last commercial using 13" wheels / tyres but that's been out of production for some time.

 

Converting from 13" to 14" inch isn't simple. The increase in ride height is no great concern as it is less than the height variation caused by diferent section tyres. 14" caravan wheels are all (or virtually all) 5-stud whereas 13" caravan wheels are generally 4-stud. Various cars were fitted with 14" 4-stud wheels of the correct pitch diameter (PCD) but their offset is likely to be different to that used by caravans. Alloy wheels are available with almost every combination of diameter, offset, stud holes and pitch circle BUT these often won't take the weight of a modern caravan.

 

The only practical solution in the near future will be to source a pair of 14" alloys, designed for the loads involved, however much time & money that takes and then fit a pair of 14" tyres for which there is much wider choice.

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Thanks, David (Klyne), fo explaining my points.

 

Tyre suppliers can only advise if they know the gross weight that will be used. I understand dsms's predicament if the rating plate is missing but underlines the need NEVER to buy a caravan with missing or tampered rating plate - it indicates fraud or theft.

 

R/F, 6-ply, 8-ply and C tyres are rare now in 13" sizes as caravans and commercial vehicles have long since moved up to 14" or 15".

 

Kumho make a 165 C13 which is rated as 94N which would suit an MTPLM up to 1340 kg. These use a tyre pressure of 65 psi at max load, but this can be reduced proportionately for lower loadings.

 

My 2001 Pageant has these tyres, the last year before 14" became standard. Bailey recommend 54 psi at the Pageant's 1218 kg MTPLM. They ride very smoothly, once they were balanced.

 

Check your local tyre suppliers. They'll almost certainly have to order and will probably need time just to quote a price.

17594[/snapback]

 

The plate on the van is not missing and has NOT been tampered with or altered in any way (in my post I said id did not show the information) , the plate in question does not show any Max weight only an ULW Chassis number etc. (BTW the van was purchased with full documentation from a friend of 20years plus standing who had owned the van from new - he was unable to answer my query either)

It is only modern vans that display this info on the plates and the original handbook does not show such information either.

 

Had been offered Kumho tyres with the 'correct' width of 175 which is are a C13 but in an 8 ply. Have gone with local tyre dealers recommendation and ordered GT Maximiler 175/13 C 6 ply's which we are assured have suitable load ratings for larger vans than ours, so quite content now

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Having owned caravans from the '80s, I know that they ALL were plated with a gross weight when new. It was and still is a legal requirement for all trailers to be so marked. How else would the police or vehicle inspectorate know if your trailer is overloaded, even when weighed?

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