Out of shape Tyres

[johnandrew70]

Just returned from a week in south Devon but found that i had a wobbly trip home, first i noticed when i slowed down in traffic the car felt like it was going up and down like the caravan was pushing and pulling up and down making it feel like we were driving over lots of sleeping policemen, as i accelerated it levelled out and began to drive a bit better but looking in the rear view mirror i could see the van was kind of bouncing constantly like as if it was driving over cobbles. i stopped in a layby to check everything was ok and that the tyres hadnt gone flat and noticed the tyres looked peculiar in that they looked rounded accross the tread almost as an inner tube would look when inflated..
Then i noticed the date on the tyres 5006 (5th week of 2006).
Firstly would the tyres looking like they do give the problems i experianced on the way home.
Secondly i bought this van from a dealer in april, i glanced at the tyres when i took delivery of the van and looked like new but surely the dealer should have put new tyres on before selling it??

John

 

[Sproket]

John
Get them changed asap you are lucky that they did not blow out on you........
Google Matador tyre problems........

What size are they ?

 

[johnandrew70]

John
Get them changed asap you are lucky that they did not blow out on you........
Google Matador tyre problems........

What size are they ?

thanks sprocket
the size is 175 r14-99

 

[otherclive]

Agree they should be changed but as there are no laws against over age tyres the chance of redress from the dealer is low, but you could give it a try. I fit commercial van tyres such as Firestone Vanhawk on mine as they are made for a hard life, price is competitive and they are likely to be newer when you buy them. Some caravan tyres can be 12 months old when fitted.

 

[johnandrew70]

i know what you are saying re the dealer.
Just hope by changing the tyres it stops the problems i had, i checked the pressures when i got back and they were saying 65 psi which is what is printed on the plate by the door but even so it still seems very high to me.

John

 

[ProfJohnL]

Hello John,

There has been a history of problems with some Matador tyres, but without knowing what batch numbers and sizes of tyres were involved I cant tell you if yours are some of the affected tyres. However any bulging deformation of a tyre must be taken seriously, and they must should be changed asap. Whilst it seems probable that bulging tyres will cause the type of towing symptoms you describe, There are other possibilities, for example if you have kerbed the caravan wheel, that could distort the rim, and incidentally damage the tyre, with symptoms of bulging, so its uncertain if the bulging is the symptom or the cause.

As others have stated, tyres on new caravans can be already many months old, its simple that caravan manufactures will by tyres in bulk. It certainly is not the case that dealers will automatically fit 'new' tyres when they sell a caravan.

As to the pressures, just consider that most cars have tyre pressures in the region of 30 to 35psi. Cars tend to weigh about 1.5 tonnes, but that weight is shared by 4 tyres. so that is typically about 350 to 400Kg per tyre. Caravans can also weigh in the region of 1.2 to 1.5 tonnes but this is only shared by two tyres so that is roughly 600 to 750kg per tyre so its easy to see that for the caravan tyre to present the right contact area with the road it will need roughly double the pressure, so 65psi is not so unreasonable.

 

[johnandrew70]

Hello John,

There has been a history of problems with some Matador tyres, but without knowing what batch numbers and sizes of tyres were involved I cant tell you if yours are some of the affected tyres. However any bulging deformation of a tyre must be taken seriously, and they must should be changed asap. Whilst it seems probable that bulging tyres will cause the type of towing symptoms you describe, There are other possibilities, for example if you have kerbed the caravan wheel, that could distort the rim, and incidentally damage the tyre, with symptoms of bulging, so its uncertain if the bulging is the symptom or the cause.

As others have stated, tyres on new caravans can be already many months old, its simple that caravan manufactures will by tyres in bulk. It certainly is not the case that dealers will automatically fit 'new' tyres when they sell a caravan.

As to the pressures, just consider that most cars have tyre pressures in the region of 30 to 35psi. Cars tend to weigh about 1.5 tonnes, but that weight is shared by 4 tyres. so that is typically about 350 to 400Kg per tyre. Caravans can also weigh in the region of 1.2 to 1.5 tonnes but this is only shared by two tyres so that is roughly 600 to 750kg per tyre so its easy to see that for the caravan tyre to present the right contact area with the road it will need roughly double the pressure, so 65psi is not so unreasonable.

Hi Prof John
The tyres on my van have not got bulges in the side wall,They look and feel overinflated by rubbing my hand accross the tread you can feel that its rounded like an inner tube the pictures dont really show it that well but imagine the centre three quaters of the tread is raised and rounded,
the tyres are 7 years old and are in need of replacing and if i knew that before i went away i would have changed them but i dont understand how a Swift assured dealer did not change them when they sold me the van. I know dealers whether car or caravan cut corners to save a few quid but this could be life threatening.
I read somewhere that the The BTMA (British Tyre Manufacturers’ Association) recommend that caravan tyres should be replaced when they get to 5 years old and if the tyres are inflated over 50psi they should be changed every 3 years.
mine are 7 years old and are inflated to 65psi .
John

 

[johnandrew70]

Also forgot to mention when trying to engage the mover both before leaving to come home and when parking van in storage it was very hard to engage took a bit of strengh to pull the bar.

 

[Dustydog]

Hi John

Just catching up here in West Yorkshire. Son gets married tomorrow.

A stiff mechanism on the mover is usually just a matter of lubrication. Check the lube points.
The tyresare a worry for me. Maybe you need to add this to the other issue you have with the dealer.
Tyres must be renewed very 5 years or earlier.
Good luck.

 

[johnandrew70]

Hi John

Just catching up here in West Yorkshire. Son gets married tomorrow.

A stiff mechanism on the mover is usually just a matter of lubrication. Check the lube points.
The tyresare a worry for me. Maybe you need to add this to the other issue you have with the dealer.
Tyres must be renewed very 5 years or earlier.
Good luck.

Hi DustyDog
the mover is fine until it meets the tyre then you really have to put all your weight against it.
As for the dealer, i am still awaiting an outcome to the blind issue.
I will order a couple of tyres on monday when i get into work a friend has a set of winter wheels i can borrow so one evening i will pop over and get the wheels off.
has anyone got any favourites when it comes to caravan tyres?? or do you all go for Firestone vanhawks also the plate on the van states Tyre size 175 R14 99 but does not state an aspect ratio.
sorry is i sound thick

I hope you have a great time at your son's wedding Dusty
John

 

[Dustydog]

John.
Our Powrtouch needs alot of muscle to fully engage the rollers against the tyres. This is normal. Seehow far the rollers press into the tyres.i do have to put my full 15+ stone to engage.

 

[johnandrew70]

John.
Our Powrtouch needs alot of muscle to fully engage the rollers against the tyres. This is normal. Seehow far the rollers press into the tyres.i do have to put my full 15+ stone to engage.

 

[Sproket]

John
What is the MTPLM of the van & do you carry everything inc: the kitchen sink

 

[johnandrew70]

John
What is the MTPLM of the van & do you carry everything inc: the kitchen sink

mtplm is 1500 we have a flat screen tv, 7 kg gas bottle lightweight porch awning uder the bed and a few other small things cloths etc the wife wants to bring the kitchen sink and bath haha

 

[johnandrew70]

John
What is the MTPLM of the van & do you carry everything inc: the kitchen sink

 

[Sproket]

Have a look at this chart !

Not a lot to play with ?
How about the 185R /14C they would be better suited for the weight of your van ?
Would depend on if you have shock absorbers fitted & how close the tyre is to them now ?

 

[otherclive]

With the 99 load index tyres the max axle load of 1550kg is above the vans MTPLM and an extra margin would be useful. However there are margins built into tyres for loading and the rated continuous speed is well above what a caravan is legally allowed in UK and most of Europe. So if OP cannot fit the bigger size then he will be okay with the makers rated size. For 175/14 or 185/14 the aspect ratio is a standard figure I think its 80% but this should be checked. Most important is to ensure good quality commercial van tyres such as Firestone Michelin Hankook Bridgestone etc. Stick with well known brands for added peace of mind. As Prof John says they are much higher loaded than your car tyres. Most caravan makers now seem to have got the message and fit good quality branded tyres.
Just a thought going to 185/14 will give a larger diameter tyre which may have clearance problems. I had a similar issue on my van so went to 185/75/14C with a load index of 102. Firestone Vanhawks come in this size others may do so. Being a 75% aspect ratio they retain the same rolling radius without radial clearance issues. If you look on the GT Radial Eu not UK website Van section you will see for various sizes of tyre the overall diameter for different sizes of tyre. This will show you how the diameter and width vary with the different sizes. I have one of their Kargomax ST 6000 as a spare its a different size cf to Vanhawks fitted to my road wheels but it is OEM size being wider than the Vanhawks currently fitted but the same roling diameter.

 

[johnandrew70]

Thanks for your replies, I dont have shock absorbers so i guess i could go to 185s.
i will get the parts guy at work to price some tyres up from a tyre supplier in Bristol that we use, they are usually very good and cheap too.
as far as weight is concerned we do tend to travel light we dont take a large awning even though we have one, the mtplm is 1500kg so that leaves me about 200kg to play with,
TV, 3kg
lightweight awning. 10kg
sat dish tripod etc 15kg
cadac, 6kg
gad 10kg
other bits and bobs would probably add up to 40kg

Thats less than 100kg

John

 

[johnandrew70]

Ok everyone Igot a quote for tyres from a supplier we use at work, They have suggested Kumho Caravan/van tyres at £56+vat each.
Does anyone have any dealings with Kumho tyres on a caravan?? i have had them on cars in the past and have been very good.
John

 

[Sproket]

Your choice John
But I wouldn't touch them with a barge pole
Buy a better quality tyre as cheaper is not always best

 

[otherclive]

I assume they mean that they are commercial van tyres that would be a suitable size and load rating for your van. To my knowledge only GT Radial Kargomax ST 4000 and 6000 are specific trailer tyres and their sidewalks are embossed accordingly. Ie Trailer Use Only.
Regarding Kuhmo they are a well established Korean make and are fitted by Kia and Hyundai as OEM equipment. I had them as OEM on my 2004 Sorento and never had any problems. I've also had their All Seasons (mountain symbol) tyres on our Nissan for two years now and again no problems with wear or performance. If you were driving a Transit for FedEx you might find their grip and handling perhaps not quite as good as say Bridgestone but on a caravan that's not so important as your not pushing the tyres to their handling limits as in a Transit. Are the tyres you are thinking about giving you a higher total load capacity than your original Matadors? Not that you can use the load but it will give you more of a margin over your MTPLM.
Like Hankook are OEM to Mercedes Kuhmo were designated an OEM supplier to Benz trucks in 2009. They are also exclusive supplier for the new Mini GP.

 

[Gagakev]

Hi John, recently had Continental Vanco tyres fitted to my van £90.00 each, including the vat, balancing, and fitted to the rims.
Mine are 195/70 R15 and also at 65lb pressure,
Interesting you say it's recommended to change them every 3 years, do you have a link to this info?

 

[Sproket]

They must have sorted out there quality control then after all of the problems to get OEM supplier status ......

 

[johnandrew70]

I assume they mean that they are commercial van tyres that would be a suitable size and load rating for your van. To my knowledge only GT Radial Kargomax ST 4000 and 6000 are specific trailer tyres and their sidewalks are embossed accordingly. Ie Trailer Use Only.
Regarding Kuhmo they are a well established Korean make and are fitted by Kia and Hyundai as OEM equipment. I had them as OEM on my 2004 Sorento and never had any problems. I've also had their All Seasons (mountain symbol) tyres on our Nissan for two years now and again no problems with wear or performance. If you were driving a Transit for FedEx you might find their grip and handling perhaps not quite as good as say Bridgestone but on a caravan that's not so important as your not pushing the tyres to their handling limits as in a Transit. Are the tyres you are thinking about giving you a higher total load capacity than your original Matadors? Not that you can use the load but it will give you more of a margin over your MTPLM.
Like Hankook are OEM to Mercedes Kuhmo were designated an OEM supplier to Benz trucks in 2009. They are also exclusive supplier for the new Mini GP.

They are Kumho 857 Load rating is 99T and are advertised as trailer tyres on the Internet
John

 

[johnandrew70]

Hi John, recently had Continental Vanco tyres fitted to my van £90.00 each, including the vat, balancing, and fitted to the rims.
Mine are 195/70 R15 and also at 65lb pressure,
Interesting you say it's recommended to change them every 3 years, do you have a link to this info?

Hi Kev i saw it here on the National web site here is the link, Check out "Tyre Aging" down the page.
http://www.national.co.uk/information/caravan-tyres.aspx