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Quote: Originally posted by brianconwy on 12/3/2012

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Caravan wheels don't rotate any faster than washing machine drums on fast spin which are never going to be balanced.  Washing machines rely on damping.  Caravans have the weight of the van to help dampen vibrations, which maybe why swift found negligible extra vibration with unbalanced wheels. 

The effect of unbalanced wheels on cars seems to become apparent at a certain speed.  Maybe caravans never reach the speed where maximum effect occurs.

I am not arguing against balancing but if the manufacturers are not insisting on it then it might not be as important as it might appear.  After all if there was any safety issue then there would be a legal requirement for it to be done on all vehicles.

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Problem is long term safety aspects cannot be easily measured by a manufacturer. All manufactureres will have a cost vs risk analysis on their processes so they may well have decided on balance (excuse the pun) they won't bother with it.

Look at the tyres many manufacturers fit as standard, their load rating is barely covering the max permissable load and certainly doesn't fall into Tyre safe's recommended max load for example.

Anyone not having tyres balances at least when they chnage their tyres is penny pinching to the extreme IMO

'Problem is long term safety aspects cannot be easily measured by a manufacturer.'

They can't be measured by manufacturers but they can be assessed by you.  There is no safety aspect that has been caused by wheels out of balance on caravans.  There has been problems with blow-outs which have nothing to do with balancing.  I am not advising not to get wheels balanced, just that the people are exaggerating the consequences ( if any ) of following the manufacturers lead.

I don't accept that manufacturers balance the danger to peoples lives against saving a few pence on a £20,000 vehicle.  When safety is an issue products are recalled at astronomic expense. 

We can all have opinions but none of us has conducted the research that the manufacturers have.

Thanks all, many interesting points here - too man y to respond to all, however, a few points- the firm in question are used by local caravan stockists and are supposed to be specialist caravan tyre fitters, Ive never used before and this was why I was surprised by their response. Additionally, as I cant get work done at storage and my drive slopes I took the van to them. Total bill ended ub nearly £40 dearer than Tescos (use e-tyres I believe), plus a 25mile round trip.

If , as we all know, unbalanced car tyres can cause shake and steering wobble, the same will happen to caravan wheels, the fact that we are not aware of it would in my opinion be worse. Would have had tham take the tyres off if they had refused to balance them, which as I said caused them quite a bit of work, especially as they had to take one tyre off and rotate it to get it to apoint they could balance it.

Wasnt very happy about the originally offered 2 year old tyres either!!

Wasnt very happy about the originally offered 2 year old tyres either!!

So with all this damage to the equipment and the van, why would the manufacturers pay out on all the warranty claims rather than balance the wheels for very little extra cost.  If people are worried about tyres going out of round then tyre savers are essential yet how many people use them?

'When a tyre is heavier in one place, the effect of centrifugal force is to throw that place further than the rest of the tyre.'

The weights go on the wheel so the tyre will still suffer these effects, but the stress on the bearings will be reduced.

'Safety issue???? Or am I exaggerating?'

Yes. All supposition.

'If the weights going on the wheel make no different to the tyre going out of shape, then why or how does the assembly come into balanced?'

If you hold both arms out with a sock in one hand with a heavy rock in it, and the spin around, then the sock will stretch and there will be a force tending to pull you over.  If you the hold a hammer in the other hand with the same weight and repeat, the force pulling you over will be counterbalanced but the sock will still stretch. 

I agree with Phil in that there is no downside to balancing the wheels but I also go along with Swifts exhaustive testing that showed very little difference in vibration levels and far less than vibration caused by road surfaces. 

Of course if you are going to get them balanced then it needs to be done regularly and tyres supported on tyre savers or the van moved regularly.  Other factors like the addition of a locking bolt might alter the balance.

Quote: Originally posted by brianconwy on 12/3/2012

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'Problem is long term safety aspects cannot be easily measured by a manufacturer.'

They can't be measured by manufacturers but they can be assessed by you.  There is no safety aspect that has been caused by wheels out of balance on caravans.  There has been problems with blow-outs which have nothing to do with balancing.  I am not advising not to get wheels balanced, just that the people are exaggerating the consequences ( if any ) of following the manufacturers lead.

I don't accept that manufacturers balance the danger to peoples lives against saving a few pence on a £20,000 vehicle.  When safety is an issue products are recalled at astronomic expense. 

We can all have opinions but none of us has conducted the research that the manufacturers have.

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As you correctly say we all are just discussing here - I do however have knowldge of large scale production and you would be surprised at what is done in nature of cost cutting. Saying manufacturers wouldn;t do it just based on cost is not correct i am afraid (much as we might like to believe otherwise)

Pennies and pounds are saved in areas that have large scale effect of profit margins on production lines and as I said above a risk reward analysis would be done to see if they can get away with not bothering to balance wheels as it saves money and apparently has no obvious detrimental effects on safety (although does apparently in many cases on handling of van)

As it costs so little why would anyone not do it would be my question. If it wasn't worth doing then you wouldn't do it on your car either would you?

Saying all that I do think correct inflation pressures and correct loading rating for tyres is far more of an important angle to get right first (load rating on caravan tyres is another example of cost cutting in previous years)

I used to work in the QA department of a firm making parts for Nissan, jaguar, Vauxhall and Land Rover.  Modern quality systems have been refined which is why cars are so reliable.  The cost of recalling cars and replacing components is prohibitive and also there is the PR disaster of any safety recall. Firms like Nissan would stipulate how the product was to be manufactured even down to requiring certain types of gloves to be worn for some tasks.Their attitude to good QA is that it saves money and so a few years down the line they expect the production process to be continuously improved and the supplied item to be cheaper.

QA in the caravan industry seems to be a different matter altogether but as you say the cost of balancing wheels at the factory would be negligible and I believe Swift in their assertion that their testing showed there to be little extra vibration and the cost of balancing was not a consideration as the testing done would have covered the cost of balancing the wheels of thousands of vans..

I think if you are going to balance your wheels then it is pointless if it is done and then not redone on a regular basis.

One of the foundations of QA is that anything should be made good enough to serve the purpose the customer needs it for.

As for your use of the term mythology then you will have to take that up with swift.  They have the only forum I know of that is run by a caravan manufacturer where they address queries.  There are many posts on the forum on this subject and anyone can look without joining the forum.  e.g. see this one.

Forums are not full of science just opinions like yours and mine.  As far as I know Swifts figures and detailed accounts of their testing aren't available.

I have always had my wheels balanced when having tyres fitted as I can't see any downsides, but having not done any testing on a circuit myself I wouldn't argue with other peoples testing.