Tyre load index.

[Gareth111278]

Hi does anyone know what load index tyres i need for my 1200Kgs MTPLM single axle caravan.

I think 600Kgs each [91 index] will be too little, i need some tolerance, i was thinking 800Kgs each [100 index]

The caravn isn't here or i'd go out & check!

any advice?

Cheers Gareth

 

[Brum1]

Paste this into your browser. It will answer all your questions.

http://www.carbibles.com/tyre_bible.html

 

[gary]

your right, you need to be 10% or above on the load rating so next up on 660kg or a bit more, don't though go massively over!!

This links specifically about tyres when fitted to caravans

http://www.tyresafe.org/data/files/caravan 08.pdf

 

[Lutz]

Although some sources recommend a safety margin over the minimum, it is not absolutely necessary to apply this to caravans and trailers because these never reach the speed that the speed rating allows, i.e. the lower speed than what the tyre permits is already an adequate safety margin. In fact, for this same reason, some caravan manufacturers even fit tyres with load ratings that are actually less than what you would expect to need.

 

[Lutz]

Although some sources reccomend an additional safety margin, this is not absolutely necessary for trailers and caravans because these never reach the speed that the tyre's speed rating allows, i.e. the lower speed is already a safety margin. In fact, some caravan manufacturers take advantage of this and actually fit tyres with an even lower load rating than what one would expect to need.

 

[gary]

Depends Lutz on if you read the European tyre manufactures general advice or the caravan specific advice from the British arm? as per the link I posted

The British say add another 10% to the 10% generally accepted as the speed reduction bonus, in other words an overall 20% safety margin

Of course that's not counting the built in safety margin at the full load and speed, perhaps another 10% or more? and why I suggested not to go overboard on the actual load rating

 

[otherclive]

I have a Series 5 Pageant that was upgraded by Bailey from 1360kg to 1400kg MTPLM. The tyres are rated at 700kg, which gives no margin other than the conservatism in the tyre design and van usage.

 

[g_374369443]

Tyre ratings are based on max load and there speed rating, if the tyres,are at the correct psi, and have no damage then the safety margin is huge on standard fitments anyway.

If the tyre is rated at only 112 mph,and you tow abroad at even 80mph, the difference in the heat build up between even those speeds are far greater than a mere 10 or even 20% that some feel they need to build in. so when towing at 60 mph the build in safety margin is more than expectable,even if you tow to the max weight.

And indeed there is an argument to say if you fit higher loaded index tyres, you could be running them too cold,or even outside the wrong psi settings,for your outfit.

 

[gary]

I'm under the impression the extra is not for while in use but when stood doing nothing.

It's these long periods of inactivity that is blamed for some premature failures of tyres fitted to caravans, it's this that makes them a unique case.

While a tyre is is constant use and for the reasons g outlines, there would be no reason to add anything to the specification.

While the van is stood the tyres are still being affected by sunlight etc, plus the tyre is 'setting' in the position it is in.

Problem is then vans hitched up and could be immediately dragged down a motorway at 60mph?! what damage does that cause that then manifests itself a few hundred miles later?

I'll also add, out of balance is another cause so all tyres should be balanced

 

[Gareth111278]

All very interesting.

I had chance to pop down and look at the caravan today, its on 91 index 925Kgs each i think so i'll put the same or close as i can get back on.

I'm changing at 5 years old not because of wear.

Thanks for all you're help . I'll le you know what i pay for them.

Cheers Gareth

 

[Gareth111278]

All very interesting.

I had chance to pop down and look at the caravan today, its on 91 index 925Kgs each i think so i'll put the same or close as i can get back on.

I'm changing at 5 years old not because of wear.

Thanks for all you're help . I'll le you know what i pay for them.

Cheers Gareth

Sorry, 91 index are 615 each, thats only 30 kgs over MTPLM. But if thats what it had from new, i'll put the same back.

 

[Lutz]

I'm not criticising anyone for selecting a tyre with a higher load rating and I am not denying that several sources suggest an additional safety margin, but it is nevertheless permissible to use a tyre with a load index that is 10% BELOW the calculated actual maximum load provided the speed does not exceed 100km/h (60mph). This would suggest that there is already an adequate safety marg