Dangerous outfit

[cris_408518]

Well Lutz you bring us exactly back to what I said before.

You have now posed it back to similar outfits one running on single and the other on twin axle at 60mph.

You are telling us all that as you have no piece of paper that you expect the single axle tyre blow out or puncture to be as safe as the same problem on a twin axle that has something to hold the damaged tyres side up and wheels that help keep it from weaving about.

No doubt taking this argument to Paddy Power whose experience is in the world of betting you would expect to get the same odds on the single as you would the twin ;-)

I assume also that I was also wrong ever to have ever expected the damage to a wheel rim of a single axle trailer when it happened unlike no damage as the twin axle trailer kept the damaged rim off the ground.

I am sorry to be so stupid as to have worked out that when the single axle tyre went that it would hit the road and dig in unlike the twins that still had a tyre that had a very good chance of holding it up.

No doubt the police officers in Wales would have had me drag a single axle caravan to Asda as it dug up the tarmac and damaged the wheel rather than the twin that ran smoothly on three wheels with no damage.

When you get home Lutz might I suggest that that you deflate one tyre on your caravan and tow it for twenty K's and then deflate one tyre on a twin axle and attempt the same route!

I'm sorry that I don't have data to show which will perform better ;-)

My humble experience suggests that with the twin you might make it un challenged but with you single axle van I think you might might draw a litle attention from others on the roads ;-)

 

[Lutz]

I have no proof that single axles are any worse and you have no proof that twins are safer so let's give the discussion a rest and wait until someone does.

 

[sparkes]

Can I make a comment here.

I agree with Lutz that a single axle van is no less stable than a twin if loaded correctly and towed within specs. A twin will hide bad loading better up to a point.

Punctures, Singles and TA are subject to this but there is no way I would tow a twin on a single wheel on one side, it will overheat and overload with catastrophic damage.

Bikes, Cris you cannot take any likeness to a caravan as the caravan wheels are parrallel to the direction of travel and the bike is series. stability of a bike is nowhere near that of a caravan. centrifugal forces on a bike wheel force it to stay upright during movement and these forces are changed on a blowout thus destabalising the bike. on a caravan, the blowout does not change the upright nature of the wheel and so you do not get the same forces in action.

Can I suggest you both agree to differ and drop the subject. no one is going to agree on the physics without proof and its getting heated

Steve

 

[cris_408518]

That's very good Lutz

You just ignore the obvious facts and common sense and bury your head in the ground re what I suggested.

You know you are on a looser and have retreated to your bits of paper.

You know as well as I what would happen if you tried to tow your van on one wheel !

Lutz I have a lot of respect for many of your posts as do other here and the call for Lutz is a welcome addition to many a question.

But ignoring common sense and obvious results as you do not have data to back up what is simple understanding is a some what strange attitude.

Our various twin axle trailers and others we know have been towed on three wheels at times be they caravan or other style trailers. We have never ever had a single axled trailed vehicle that could be towed beyond where a tyre has failed and the vehicle has stopped bar for a few metres that often cause further damage to get the trailed vehicle to a safer place to jack it up. Even at around 30 mph I and others have had to have wheel rims replaced when the twins second wheels have prevented such damage.

How you can dismiss this from not translating to safer towing is a mystery.

A gun will only kill you when the triggers pulled, all caravans I guess are safe until someone pulls the side out of the tyre.

Saying there is no data to say that 4 tyres offer better protection than two is to all I know beyond belief apart from any other factors re 4 wheel caravans.

Re Sparkes point.

No one will tow a twin axle on three tyres unless forced to if they have anuy sense.

You do know that there is a problem and the tyres are normaly over their load limit. The point is that, as with my tyre damage in Wales we could tow the van very slowly a short distance to a safe place where as a single axle would have to have had the road closed off or have been dragged causing more damage.

ps

Comparison re bike Sparkes was only re loosing 50% of the tyres.

In theory the bike has tyres the same as a cars but only two as opposed to four.

As you say the dynamics and forces on a bike are different to a cars ( have you data for that ;-).

Its a simple fact that does not need an Einstein to know that a four wheel caravan losing one tyre is likely to stay more upright than a two wheel one. If one can not equate that to danger I'm lost!

I know of cases where a twin axles tyre failure caused side wall damage due to weight transference to the remaining tyre and one case involving a caravan at quite his speed that was able to be brought to a relatively simple safe stop.

 

[Lutz]

I take exception to your comments regarding ignoring common sense, Cris. I don't know what the ability to tow a twin on three wheels has to do with accident rates. Besides, the whole issue of how a single or twin reacts in the event of a puncture has been grossly overrated. I have been driving for 40 years and have suffered one blowout in all that time (and that was driving solo).

 

[cris_408518]

Lutz.

Why are you now talking about accident rates ?

You are very fortunate to have had one blow out is 40 years.

I wish could say the same.

The ability that a trailer can still be towed quite well on three wheels when a twin wheel losing one tyre can't has nothing to do with accident rates, but is likely to prevent an accident where a lot of the time the single wheel digging into the road is likely to cause one.

That is common sense I'm afraid Lutz.

If what you say means that you have never had a trailer/caravan trailer rapidly deflate in 40 years you show no respect for what others I know regard as valid and valued advice based on a lot of experience.

Long may you and I continue towing on fully inflated tyres as I can tell you that you will be lucky to get away with a tyre deflation on your single axle caravan as well as I or Steve would travelling with similar loads at similar speeds with a twin axle.

How you can say that a single axle that more than often has the wheel rim rip into the road and throw a car and caravan in all directions compared to a twin that will still mainly run quite smoothly and evenly on three wheels before brought to a hault is grossly overated I will never know.

Does an air bag have anything to do with accident rates? I think not, but plenty are glad they are there when they go off and they don't meet the steering wheel.

Likewise should I lose one of four caravan tyres I will be pleased that the caravan is still likely to have the rolling ability rather than wheel rim argue with the road with the potential dangers that I have experience of with frightening likeness to many others reports.

 

[Lutz]

Lutz.

Why are you now talking about accident rates ?

I have been talking about accident rates all the time. It is you who have been constantly diverting from the subject.

You still go on about the hazards of the rim hitting the road without any indication of the actual level of risk of the consequences. I get the impression from your replies that loss of a tyre and running on a rim is the precursor to impending doom.

 

[cris_408518]

I made original comment re safety when something goes wrong Lutz.

When you mention impending doom mine and others experiences of losing a tyre on a single axle caravan apart from any other road incidents when towing is one of the closest I and my family have come to doom. Our first tyre problem happened at just under 30 mph on a French road, the wheel rim biting into the road threw the car onto the wrong side of the road and back onto a grass verge on our side before dragging the car back half onto the road. An experience similar to losing a tyre on a friends single axle trailer that was much lighter and smaller.

When describing what had happened when we got to our campsite, others expreesed the same sort of experiences with single axle caravans.

Over many years since, "impending doom" sums up well most comments re losing a tyre on a single axle and campares very well to comment re the same with single axle trailers.

10 out of 10 Lutz. As my wife saw the white of the eyes of oncoming driver when our first tyre went it is something she has discussed with other ladies as the one thing they fear mainly re caravanning based on experience.

When we first started to look at twin axle caravans and seek advice from users on sites, we received very many comments on better stability and the relative calm re what happened when a tyre went.

Of course we had no data on paper but so many similar positive remarks were enough for us to decide to pay a little extra for a T/A van when we upgraded and when placed with tailer experiences that to us confirmed our safety concerns. More than one couple told us what to expect on a twin re handling and and tyre loss, all remarks were positive and I beleive we have proven to ourselves and talking to others since joining the T/A club all seem to agree. In general the only negative re T/A's is re siting the van due to the second set of wheels, but that can be overcomme with a little thought and care.

The general theme re T/A tyre loss compared to S/A we have found is that with rapid deflation you are mainly a passenger in your own car and having little effect on what happens when all hell suddenly breaks loose when a S/A's tyre goes, by comparison with a twins rapid deflation you will normaly get a warning as the vans puts more pressure on the remaining tyre and you start to slow and even if the second tyre blows or deflates the wheels in line make the rig easier to control.

I've yet to meet anyone who has had the horific ride that a single axle tyre loss can give compared to those who have experienced the same on a twin like us.

 

[Lutz]

How can you be so sure that under the same conditions that you experienced you would not have been quaking at the knees just as much with a twin? When other owners of twin axles reported of relative calm when they experienced a puncture were these conditions comparable?

If there were such overwhelming endorsement for twin axled caravans, single axles would have been made illegal a long time ago. There would also have been a demand for run-flat tyres as standard fitment, in particular on single axles. The problem cannot be that great because I don't know of any caravan manufacturer that even offers them as an optional extra. At the very least, insurance companies would be putting an extra premium on the use of single axled trailers and caravans by now, knowing how eager they are to find any excuse to raise premiums.

 

[MikeP]

"I've yet to meet anyone who has had the horific ride that a single axle tyre loss can give compared to those who have experienced the same on a twin like us".

A previous thread on this forum suggests that you are unlikely to have a puncture on a caravan in several years. I have had two punctures in about 13 years, if I remember rightly. One on a trailer tent in 1994, and one on a Scenic in 2000. Many people cited similarly long periods and huge mileages between punctures, but a few others had been less lucky.

When I meet other caravanners we might talk about the weather (being British, this is essential), holidays, traffic, family, cycling etc. The subject of punctures would be way down my list.

It does look as if Cris has had more than his fair share of punctures. In fact, he and his many works trailers seem to have had everyone's share.

 

[cris_408518]

MikeP.

At this moment we have a trailer in Malmo on it second trip in six days from the UK and another two in Valencia another is somewhere between UK and Saltzurg. We still have a 3500KG flat bed Iffor Williams and three others not working partly as I'm on long term sick and will proabably only ever work part time again.

Apart from caravanning with family we've also used a caravan on long distance European work at times. As my annual towing mleage with caravans and trailers has been far more than the total average mileage for a UK motorists and that does not include towing racing trailers.

Our associates and friends nearly all tow trailers for work and as Brits working around Europe we have quite a good self help network. Towing near non stop for over 600 miles in a day has been a regular work day for a long time.

Others here quote total annual mileage including towing of 10000 miles and less whilst my brother inlaw and I guys that work with us tow 300000 plus a year.

We could also probably entertain you with the stories like a trailer tyre blow out as the van and trailer hit a road that had not been tarmaced and had no warning signs, one minute they were on tarmac highway and then a big drop and a hard rubble road. Another where bother inlaw swerved off the road as loads of plum tomatoes fell from a trailers side in Italy. If you do high mileage and often in strange places you tend to get the odd problem !

 

[seth1]

hello cris,i have to ask the 300000 miles a year is that correct,or have i misread it,that is some serious milage.

 

[cris_408518]

Sorry for the typo!

Should read 30000 Plus

 

[seth1]

that sounds more like it.thats like 3 times the average,so really your 3 times more likely to have a problem with something.

 

[seth1]

as an owner of a s/a van surely tandems have got to handle better,and in away safer because they could prevent an accident.lets face it you,ve got an other 10" of rubber in contact with the road.you can,t deny there is more grip.and this alone has got to help keep them steady.

 

[cris_408518]

I'm not prepared to comment Seth, as I don't have a piece of paper from a scientist or the like! Also as any personal experience is worthless it seems according to Lutz.

Others are prepared to let me loose in very expensive race cars to aid and advise on set-up and I have no data re doing that either ;-)

 

[ProfAlGoogle]

Just to add, I have towed t/a caravans and single, and to be perfectly honest they both behave in about the same manner, but it is more peace of mind for me knowing that I have another wheel in contact with the road surface in the situation of a blow out, but at present I am towing a single axle Bailey Senator that behaves impeccably. In my humble opinion, to make them more stable you would need to have a spread axle as opposed to a close coupled arrangement as we did on HGV'S before we had tri axels that were mainly used for continental work in those days.

Allan.

 

[Lutz]

As so much emphasis is being placed on the consequences of a puncture, I reckon fitting a run-flat tyre on a single axle is a cheaper and more lightweight solution to overcome the potential hazard than a twin.

 

[ProfAlGoogle]

As so much emphasis is being placed on the consequences of a puncture, I reckon fitting a run-flat tyre on a single axle is a cheaper and more lightweight solution to overcome the potential hazard than a twin.

What about tyron bands Lutz? any good.

Allan.

 

[cris_408518]

Just to add to this I emailed the bulk of this thread to two friendly associates one is a tyre techician for a large tyre manufacturer.

He pointed out the following, given like for like tyre failure on identical single axles but with tyres having different pressures he would put all his years of experience on the lower pressure tyre failure being a less violent affair that will more than likely give the driver an easier control of the vehicle involved.

All though there are differences in tyre construction a single axle caravan tyre running at 50 psi or more will be far more explosive like in a controlled failure than a twin axles tyre running at around 35psi. Attaching the tyre to their respective similar weight and sized caravans apart from the more explosive nature of the higher pressue tyre it will also suffer the weight forces as there is no second tyre to take the weight or cushion in it.

His veiw is that from his experience and from working at tyre production plants and tyre R&D depts carrying out new tyre design and detruction testing just the fact that a twin axle runs at lower tyre pressures will give a safety advantage over a single axle.

 

[Lutz]

For caravans, I would consider Tyron bands an acceptable, if rather crude, alternative to a run-flat tyre. Crude because they are relatively difficult to fit and require special care in doing so. I would not recommend them for any vehicles capable of higher speeds because they increase the moment of interia of the wheel assembly significantly, thus putting considerable additional stresses in the suspension and braking system.

 

[Lutz]

Just to add to this I emailed the bulk of this thread to two friendly associates one is a tyre techician for a large tyre manufacturer.

He pointed out the following, given like for like tyre failure on identical single axles but with tyres having different pressures he would put all his years of experience on the lower pressure tyre failure being a less violent affair that will more than likely give the driver an easier control of the vehicle involved.

All though there are differences in tyre construction a single axle caravan tyre running at 50 psi or more will be far more explosive like in a controlled failure than a twin axles tyre running at around 35psi. Attaching the tyre to their respective similar weight and sized caravans apart from the more explosive nature of the higher pressue tyre it will also suffer the weight forces as there is no second tyre to take the weight or cushion in it.

His veiw is that from his experience and from working at tyre production plants and tyre R&D depts carrying out new tyre design and detruction testing just the fact that a twin axle runs at lower tyre pressures will give a safety advantage over a single axle.

A blowout is a blowout, whether it occurs in 0,01 of a second or 0,1 second. The violence of a blow out is hardly going to make much difference to the way in which the outfit is going to come to a stop.

 

[cris_408518]

Well apparently you are wrong Lutz. The forces induced by extra tyre pressure regularly cause more damage to a tyre.

Like tyres on like vehicles travelling at the same speed but with different tyre pressures tend to suffer more damage on the one with higher tyre pressure.

From the other view vehicle stability is effected by yaw rates in vehicles.

Aerodynamic tests have also proven that pitching (yaw rates) trailers and caravans and sideways movement creates instability.

Pitching or yaw will also induce a weave.

The length of time a vehicle yaws the longer stability is reduced.

Theoretical views re caravan stability have been tested with different length single axle caravans which were beleived to have been supplied by Bailey of Bristol ( from Associates memory. About 3-4 years ago he thinks )

Reduction of yaw rates is considered a major handling and safety feature by Vehicle Dynamics engineers in Car, Truck and Trailer/Caravan design.

My associate does not have access to the research papers as he is a Motor Sport Dynamics engineer now, his view from memory was that the research backed up what many caravan users had long believed by at least two research studies re caravan stability.

Trailer and Caravan towing characteristics are said to be very similar.

Other experiments re Caravans and Stabilisers such as the Alko ( tow ball friction ) proved that higher nose weights offer better stability and safety.

Yawing can induce snaking and instability.

Resistance to yaw and sideways movement should be considered as a positive safety measure from the research results.

Different tow vehicle suspension is said to help but not fully compensate for trailer differences re yaw and snaking.

 

[cris_408518]

Just for fun Lutz. Your comment on this one!

http://www.practicalcaravan.co.uk/newforums/fm_messages.asp?FO=1&FM=311302
I guess if it was a twin axle two wheels could possibly have come off at the same time !

 

[BrianStAlbans]

Having had car, bike, truck accidents and race accidents and problems when towing caravans and trailers....

Not surprising really as you don't know when to stop.

This is getting SO boring.

IMHO

Brian (",)