I have had to increase the tyres size on my Knaus Starclass 560 to 205/70x15 to give a factor of safety for the overall weight of the van 1800kgs has anyone any idea of the Tyre pressures I should be using
Alan W
Alan W
Tyre Pressures
- Thread starter Alan Wilkinson
- Start date
You have stated you 'had to increase the size for safety'. That is a matter of concern. The manufacturer should have fitted the correct tyre size for the weight of the van he was selling and I would be surprised that Knaus did not do so. Have you upgraded the weight limit on the van yourself?
Either your Post is a bit misleading or you should really contact Knaus for their recommendations.
Either your Post is a bit misleading or you should really contact Knaus for their recommendations.
The full story is a blowout in France in June and a further blowout in Germany in September. The Tyres fitted were Matador 195/70x15 with a max permitted weight of 900kgs the max weight of the Knaus is 1800kgs i.e. No Safety margin. I managed to find a Knaus Agent in Germany who spoke perfect English he phoned Knaus Technical department who recommended increasing the tyre size to 205/70x15 which had a max permitted weight of 950kgs. This gives me some comfort as I think that without Tyron Bands 2 blowouts could have resulted in some sort of accident!!! The only thing they did not inform me of is the tyre pressure. At present they are at 4bar.
The recomended pressure, at what temperature and maximum permitted weight, should be stamped on each tyre sidewall by law.
It's not a legal requirement, in Europe, to have max weights and max pressures stamped on the sidewall - it only applies in the US and Canada but the information is useful for us - it may not be present on tyres not intended for sale in North America.
If the old tyres and your new ones share the same maximum pressure as stated on the tyre wall,ie 65psi, then the pressure for your new tyres will be slightly less than was recommended for the old.
I would suspect 2 perhaps 3psi thats all
I would suspect 2 perhaps 3psi thats all
Having read Alan's clarification message I am still surprised that a manufacturer would sell a caravan with tyres rated just to the maximum loading. I assume that Knaus supplied the new tyres free of charge
Depends on your view point Scotch Lad, any tyre with a load and speed rating will have been tested well beyond those figures stated on the tyre.
The faster a tyre spins the stronger it needs to be to support a given load.
Caravans in general are not allowed to get near these tyre speed limits so this gives a further 'speed bonus' to the total load and this is generally taken as 10% more than the stated load.
So a stated load of 1800kg a pair at 90mph+ means 1980kg at 60mph and in general while in constant use I could well agree with that.
However, caravans are not in constant use and it's this that allows tyres fitted to a caravan to harden/distort while stood unused.
With that in mind the BTMA recommend a further 10% or put another way, reducing the stated load by 10% and giving a 20% total load allowance to tyres fitted to caravans
Why this advice is not followed by caravan manufactures may be due to a misinterpretation of the recommendation? seems clear enough to me but as I said, depends on your view point!
The faster a tyre spins the stronger it needs to be to support a given load.
Caravans in general are not allowed to get near these tyre speed limits so this gives a further 'speed bonus' to the total load and this is generally taken as 10% more than the stated load.
So a stated load of 1800kg a pair at 90mph+ means 1980kg at 60mph and in general while in constant use I could well agree with that.
However, caravans are not in constant use and it's this that allows tyres fitted to a caravan to harden/distort while stood unused.
With that in mind the BTMA recommend a further 10% or put another way, reducing the stated load by 10% and giving a 20% total load allowance to tyres fitted to caravans
Why this advice is not followed by caravan manufactures may be due to a misinterpretation of the recommendation? seems clear enough to me but as I said, depends on your view point!
Excellent post Gary.
Alan has had two tyre incidents and is taking action to solve the problem in a comendable manner.
Just think of all the caravans spending 11 months of the year or longer in storage.
The only tyre management, being a quick pressure check before the annual trip!
Alan has had two tyre incidents and is taking action to solve the problem in a comendable manner.
Just think of all the caravans spending 11 months of the year or longer in storage.
The only tyre management, being a quick pressure check before the annual trip!
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