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Wheel Loss


the hog

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I don't wish to alarm anyone but after a near disastrous experience in France I thought I should raise awareness to the potential problem of trailer wheel loss which can obviously affect caravans.

I am totally obsessive about checking everything on the car/caravan. Both are dealer maintained regardless of cost. I never start a trip without checking everything including tyre pressures and wheel bolts.

The van went for it's annual service a few weeks before our Easter trip to France. On collecting it the dealer operates a system where the owner is requested to witness the mechanic torque up the wheel bolts prior to handing the van back.

As is advised I pulled in on the way home after 20 miles or so to re-check them. I always carry a torque wrench set at the correct setting for the van. All was fine.

The van was not then used until the trip to France prior to which I again made all my normal checks. Again the wheel bolts were fine.

Somewhere south of Calais and a total of about 200 miles from home I was cruising at about 65 mph on the motorway there was a huge bang and the van began to violently snake and pitch. I managed to maintain control and pull into a refuge, thinking the nearside tyre had blown. On stopping I was horrified to find the nearside wheel had come off. Luckily it came to rest in the central reservation and didn't hit anything else.

I am at a loss to understand how all 5 wheel bolts could have disappeared just 200 miles after being correctly torqued and am trying to get information on this problem which has afflicted the road haulage industry for years. It is more likely to affect the nearside wheel due to the direction of rotation in relation to the bolts/threads.

Has anyone else experienced it?

I am told that on hgv's the problem of wheel bolts loosening can be caused by tyre scrub when manoevring in tight spots. If this is so then it seems to me that using a motor mover would exacerbate the effect. I also wonder if having alloy wheels contributed. If anyone has any views/info on the subject I would be pleased to hear it but also wanted to highlight what can happen.

Checking wheel bolts prior to every trip is essential.

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This is very alarming. Can you confirm the wheel studs and brake drum were still in place.

 

There must be something that causes this. I'm sure it must be possible to fit locking wheel nuts to a caravan. Like the hub nut with a split pin.

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Did the dealer use any sort of cleaning or lubricating agent on the threads?

 

when you did your 20 mile check did any of the bolts actually require tightening?

 

It's a worrying tale. Especially as I'm off to France soon - after having my caravan serviced!!!

 

How much damage was done to the caravan and were you able to continue with your holiday?

 

I hope evrything is sorted out now and good luck with your quest for information.

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Lonegroover, The studs had disappeared completely but the drum was in one piece. Due to the mover being lower than the drum it took most of the impact and probably is the reason the whole thing didn't overturn. My dealer was not able to offer any solution other than confirm that this can and does happen! hence the reason for my post to try and get some answers.

Jim, Nope, nothing used on the threads and all bolts were tight at my 20 mile check.

We were able to complete the holiday after utilising the spare wheel (and checking the bolts every 50 miles or so.) As stated the mover took the brunt of the impact but there is still substantial damage to the van which is currently in the hands of the insurers.

Thanks both for your replies.

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Most HGV have left handed studs and nuts on the near side,and many pre war cars did the same. So why dont they do this with caravans?

All the Best Derek

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. I always carry a torque wrench set at the correct setting for the van. All was fine

 

Hi Hog,

 

Sorry to here of your mishap, but this is the first time I have heard of this problem for some time, hope it has not put you off too much,

 

But to the point of the post, you mention "you carry a torque wrench SET for the van" I know this was not the main reason for this time but I was under the impression you had to release the pressure on the torque wrench ! I wonder if this is why your wrench is not tighting the bolts ?

 

Steve

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Well if the torque was checked three times I don't see how that could be incorrect at the outset and responsible.

A few possibles are dirt between wheel and hub which should have settled and the re-torquing corrected.

Wrong wheel bolts/nuts used which is doubtful.

Seems to me that leaves wheel balance, are your wheels balanced?

gary1s.gif

 

Arc Systems are specialist Carver caravan product repairers, committed to providing a comprehensive service as well as spare parts for these popular heaters.

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Pleased to hear you survived without totally wrecking your van and yourselves.

 

Its of no real help to you after the event but Alko do some plastic clip on strips which stop/restrain the nuts/studs from undoing fully. One anchors against another ok for even numbers of fixings, but for 5 fixings better than nowt at least 4 will be ok. The nuts/studs may undo slightly but shouldn't undo more than 1/2 a turn. They may not but of any use on alloy wheels where the fixings are sunk in or where the Alko straps can't breech the gap.

 

It seems to me that this serious and well documented design fault should be addressed by the manufacturers. As someone said above some lorries wheelnuts and even old mini "hubs" had opposite threads for each side so that the "hub"nuts came off the way the hub normally rotated ( rule of thumb in the old days) and so tended to stay tight instead of undoing during normal use. I can understand manufacturers not wishing to produce wheel fixings with half of them left handed threads as sods law says if its possible to be done someone will try and screw in the wrong thread and damage them beyond use. I read somewhere that it is a function of the additional vibration on the wheel nuts possibly caused by the lack of dampening on the axle but surely the design gurus should be able to sort it out quite easily, they did send a man to the moon a lifetime ago. Cost of manufacture dictates I guess.

 

Maybe the manufacturers will take this one up and resolve it finally. We can only use whatever methods we have available to make it more unlikely to occur again. I now have Alko stud clamps, shock absorbers and Tyron bands all as additions to standard in the cause of enhancing my chances of it not happening to me. Not a great deal of help if a wheel come off fully but may reduce the likelihood of it happening in the first place.

 

Bob

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I have heard of this on 3 other occasions. As it so happens all 4 have been obsessed with tyre pressures and wheel bolt tightening. Have also seen this on agricultural trailers many, many times. Ask yourself this question 'How many motor vehicles, whether steel or aluminium wheels, get theire wheel bolts retorqued at every trip?' Also lorries are not retorqued on such a regular basis. Most car, caravan, trailer manufacturers recommend that bolts are torqued up on initial fitment of wheel and then retorqued after the first trip or after so many miles. NOT at every trip. Plus do not lubricate wheel bolts. Draw your own conclusions. I have never had a wheel come loose on anything I have owned or worked on in all the years I have been driving. The wheels I have had off in my working lifetime must be in the millions.

 

Hope this puts a few peoples minds at rest

 

 

Pete

Volvo
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I had a wheel come off on a boat trailer a while back but this was due to the application of an anti-seize compound applied to limit sea water corrosion.

 

All was torqued OK.

 

Never put it on again.

Stay safe - Griff.  :ph34r:

Wheels at the front Green Oval Towing Machine

Wheels at the back Bessacarr 845

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Hog, very sorry to hear of your misfortune, and many thanks for reminding us all of this very annoying/dangerous occurance.

Firstly, I use an old set of winter wheels on my van every year, and have to admit that I was always concerned when retorqueing the bolts back to 65 ft. lbs. EVERY time (steel wheels) - I wondered if this was "sufficient" with having them off so often, and thought perhaps a little more torque should be applied so that that bolts weren't "stopping" at the same place on each occasion.

Secondly, I am just in the process of changing my 'van, to one that has alloy wheels, and I notice that the required torque for them is 85 ft. lbs. , a very important point for any of us changing to alloys after being used to steels for so long. (I'm not indicating here that everyone's alloys are "85", but I think it's worth pointing out that there is usually a considerable difference between steel & alloy torques).

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Quote from Inspector Bob; "Its of no real help to you after the event but Alko do some plastic clip on strips which stop/restrain the nuts/studs from undoing fully. One anchors against another ok for even numbers of fixings, but for 5 fixings better than nowt at least 4 will be ok. The nuts/studs may undo slightly but shouldn't undo more than 1/2 a turn. They may not but of any use on alloy wheels where the fixings are sunk in or where the Alko straps can't breech the gap."

 

Unqoute; Has anyone seen "indictors" suitable for the sunk in type of bolts on alloys as mentioned in Bobs quote, the equivalent to those readily available for steel wheels? I haven't, but always found them great on the steels. If they are not available yet, I think I'll settle for a dab of tipp-ex, or similar, on the corner or edge of each bolt head nearest the centre of the wheel. - Any other suggestions would be much appreciated.

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This may sound a bit silly, but its almost as though the nuts were over tight. Could the studs have been pulled through the bub assembly and were any of the nuts still on the studs, assuming you could find them.

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I don't wish to alarm anyone but after a near disastrous experience in France. ....
Hi Hope You are o. k

From my limited general engineering knowledge, and from what I was taught on the CC towing course. Toquing and re torquing is a no no. Once you set the torque on a bolt you have to release it to re torque it. Otherwise you gradually end up stretching the bolts which can lead to failure (although usually a stress fracture). If you keep on releasing the torque on abolt then retightening it you will weaken the bolt. So it would appear that if this is done regularly then you would have to replace the bolts.

 

Jon

 

as a ps I have checked this with the engineers at the chemical plant where I work. For the pipe work and tanks or pressure vessels bolts are torqued to specification. If they need to break into the pipe again new bolts are always used irrespective of cost. May not be of much use to you now, but may serve as a warning.

You can also get little green pointers to place onj bolts so that if one is coming loose it will be obvious.

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This sounds very good advice Jonbob, and I'll definitely keep it in mind.

However, this renewing bolt rule doesn't seem to apply to car wheels, where the bolts generally outlast the car.

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Thanks for the advice, a cautionary tale indeed.

 

Just as worrying perhaps is the situation I found myself in when, having collected my new caravan, I journeyed the 200 miles home from the dealers. During the 'hand-over' by the workshop staff, nobody mentioned tha fact that i should stop after 20-30 miles to check/re-torque my wheel nuts. This in light of the fact that they knew that i was totally new to caravanning and had a 200 mile journey ahead of me! I found this advice later when having arrived home safely (thankfully) I read through the caravan brochure.

 

Defender ;)

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I have heard of this on 3 other occasions. As it so happens all 4 have been obsessed with tyre pressures and wheel bolt tightening. Have also seen this on agricultural trailers many, many times. Ask yourself this question 'How many motor vehicles, whether steel or aluminium wheels, get theire wheel bolts retorqued at every trip?' Also lorries are not retorqued on such a regular basis. Most car, caravan, trailer manufacturers recommend that bolts are torqued up on initial fitment of wheel and then retorqued after the first trip or after so many miles. NOT at every trip. Plus do not lubricate wheel bolts. Draw your own conclusions. I have never had a wheel come loose on anything I have owned or worked on in all the years I have been driving. The wheels I have had off in my working lifetime must be in the millions.

Hope this puts a few peoples minds at rest

Pete

 

Im with you on this one, once my wheels are on they are tightened up and checked ONCE after about 50 miles, and I dont use a torque wrench either, im "old school" tight is tight to me (flameproof suite is already on) oh and just to add, having changed MANY wheels on anything from HGV to trailer, upto now i have NEVER had a problem (touch wood)

 

In this instance, I would be tempted to suspect overtightening,

 

Im just glad your OK after the experience

 

 

 

Edited to add

 

Just a thought, were the nuts put on with an airgun ? they are notoriously innacurrate and could be a contributary factor

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But to the point of the post, you mention "you carry a torque wrench SET for the van" I know this was not the main reason for this time but I was under the impression you had to release the pressure on the torque wrench ! I wonder if this is why your wrench is not tighting the bolts ?
Steve, Its a fair point and worth bearing in mind but I'm pretty sure this was not the cause as all the bolts were marked with a vertical line so it was also quick and easy to visually check that they hadn't slackened off. None of them up to this point ever had.
Well if the torque was checked three times I don't see how that could be incorrect at the outset and responsible.

A few possibles are dirt between wheel and hub which should have settled and the re-torquing corrected.

Wrong wheel bolts/nuts used which is doubtful.

Seems to me that leaves wheel balance, are your wheels balanced?

Gary, Yep. New tyres fitted last year. Both wheels balanced. (Took the wheels off the van myself and took them to the tyre shop so no air gun was used.)

Wheels and bolts were originals.

Pleased to hear you survived without totally wrecking your van and yourselves.

 

Its of no real help to you after the event but Alko do some plastic clip on strips which stop/restrain the nuts/studs from undoing fully. One anchors against another ok for even numbers of fixings, but for 5 fixings better than nowt at least 4 will be ok. The nuts/studs may undo slightly but shouldn't undo more than 1/2 a turn. They may not but of any use on alloy wheels where the fixings are sunk in or where the Alko straps can't breech the gap.

Bob, Tried to get some of these strips but was told they were't available as mine are alloys with the bolts being of the sunken not surface mouted variety.
I have heard of this on 3 other occasions. As it so happens all 4 have been obsessed with tyre pressures and wheel bolt tightening. Have also seen this on agricultural trailers many, many times. Ask yourself this question 'How many motor vehicles, whether steel or aluminium wheels, get theire wheel bolts retorqued at every trip?' Also lorries are not retorqued on such a regular basis. Most car, caravan, trailer manufacturers recommend that bolts are torqued up on initial fitment of wheel and then retorqued after the first trip or after so many miles. NOT at every trip. Plus do not lubricate wheel bolts. Draw your own conclusions. I have never had a wheel come loose on anything I have owned or worked on in all the years I have been driving. The wheels I have had off in my working lifetime must be in the millions.

 

Hope this puts a few peoples minds at rest

Pete

Pete, Again could be a valid point and I would be incilned to agree if a normal wrench was used thus giving the possiblity of over tightening and damaging threads. Surely though a torque wrench simply ensures they are at the correct setting.
Secondly, I am just in the process of changing my 'van, to one that has alloy wheels, and I notice that the required torque for them is 85 ft. lbs. , a very important point for any of us changing to alloys after being used to steels for so long. (I'm not indicating here that everyone's alloys are "85", but I think it's worth pointing out that there is usually a considerable difference between steel & alloy torques).
Eddie, Setting for my alloys is 85 lbs which is what I have always used. The setting for the steel spare is lower and also has different bolts. The two have never been confused.
This may sound a bit silly, but its almost as though the nuts were over tight. Could the studs have been pulled through the bub assembly and were any of the nuts still on the studs, assuming you could find them.
Definitely not over tightened and no damage was caused to the hub. All 5 bolts just disappeared.
Hi Hope You are o. k

From my limited general engineering knowledge, and from what I was taught on the CC towing course. Toquing and re torquing is a no no. Once you set the torque on a bolt you have to release it to re torque it. Otherwise you gradually end up stretching the bolts which can lead to failure (although usually a stress fracture). If you keep on releasing the torque on abolt then retightening it you will weaken the bolt. So it would appear that if this is done regularly then you would have to replace the bolts.

 

Jon

Jon, Again a fair point but surely checking the torque is a different matter to torqueing and re-torquing which I have never done. The only time the torque has ever been released is at service. The advice I've always had is to check regulary due to this problem of bolts being able to work loose.
Hope this puts a few people's minds at rest

Pete

Im with you on this one, once my wheels are on they are tightened up and checked ONCE after about 50 miles, and I dont use a torque wrench either, im "old school" tight is tight to me (flameproof suite is already on) oh and just to add, having changed MANY wheels on anything from HGV to trailer, upto now i have NEVER had a problem (touch wood)

 

In this instance, I would be tempted to suspect overtightening,

 

Im just glad your OK after the experience

Edited to add

 

Just a thought, were the nuts put on with an airgun ? they are notoriously innacurrate and could be a contributary factor

Surely tightening without a torque wrench would be more likely to cause over tightening or am I missing something.

No air guns have been used.

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First off, re the torque wrench. A correctly calibrated torque wrench, with a person who knows how to use it on the end, is fine. A nut or bolt must be slacked off a little bit before you retorque. If I go in to how to use a torque wrench I could literally be here for hours. What can happen if you don't slack the bolt off and you snatch the torque wrench it can give you a miss-torque. Getting tighter and tighter every time you do it. The conical of the nut dishes its mating surface on a steel rim. Hence, with the weakened rim - loose nuts or bolts. This equals lost wheel. Alloy wheels have a different taper on the conical to spread the load of the bolt or nut as alloy is softer. Some even have a flat faced washer instead of a conical. Obviously you can have more problems with alloys than you can with steel. It all boils down to your nuts/bolts have got to come loose to lose a wheel. Usually the above is the reason but also you can be stretching the threads. I did a test a few years back on 6 twin axle farm trailers and I proved without doubt to both the farmer and his insurance company why he was losing wheels. It boils down to what I put in my first post. My advice to anyone who is worried about wheel bolts is buy the pointers that have been mentioned or get some thick paint and put a blob across the nut/bolt and the rim. Then everytime you use the van look at the paint for any sign of a crack between the nut/bolt and the rim. If you would like to know what the test involved where I proved my point it would be very long winded to type but I will do it if you want to know.

 

Pete

Volvo
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Quote from Inspector Bob; "Its of no real help to you after the event but Alko do some plastic clip on strips which stop/restrain the nuts/studs from undoing fully. One anchors against another ok for even numbers of fixings, but for 5 fixings better than nowt at least 4 will be ok. The nuts/studs may undo slightly but shouldn't undo more than 1/2 a turn. They may not but of any use on alloy wheels where the fixings are sunk in or where the Alko straps can't breech the gap."

 

Unqoute; Has anyone seen "indictors" suitable for the sunk in type of bolts on alloys as mentioned in Bobs quote, the equivalent to those readily available for steel wheels? I haven't, but always found them great on the steels. If they are not available yet, I think I'll settle for a dab of tipp-ex, or similar, on the corner or edge of each bolt head nearest the centre of the wheel. - Any other suggestions would be much appreciated.

 

 

There is a dab of paint on each of the wheel nuts on my 'van (steel wheels) so I can tell at a glance if the nuts have moved. For this reason, I've never fitted the hub caps.

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As someone said above some lorries wheelnuts and even old mini "hubs" had opposite threads for each side so that the "hub"nuts came off the way the hub normally rotated ( rule of thumb in the old days) and so tended to stay tight instead of undoing during normal use. I can understand manufacturers not wishing to produce wheel fixings with half of them left handed threads as sods law says if its possible to be done someone will try and screw in the wrong thread and damage them beyond use.

Bob

 

Surprisingly nearly all bikes have an opposite thread on the bottom bracket, to resist loosening while the bike is ridden, and it is rare to get a complete numpty who tries to force the BB in the wrong way.

 

I've got steel wheels, with the indicator "flags", that are checked visually. I've never had to retighten any of the wheel nuts, and have only checked them when the wheels have been off after a service.

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hog, glad you're ok.

you mentioned you recovered the wheel, was there minimal damage to the mounting holes which might indicate a more 'sudden' release or were the holes badly damaged to indicate that the bolts had loosened over a perod of time? also, could there have been an opportunity for someone to tamper with the wheels? I know that sounds like a long shot, but I think I'd almost prefer to beleive that they had been tampered with as opposed to trying to understand what went wrong given all the precautions you had taken.

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Surprisingly nearly all bikes have an opposite thread on the bottom bracket, to resist loosening while the bike is ridden, and it is rare to get a complete numpty who tries to force the BB in the wrong way.

Sorry Jonathan, but bike bottom bracket threads (and pedal threads) are left and right threads so that they UNSCREW when ridden.

If you have even ridden a fixed wheel, with tow clips, and had a pedal seize, you will understand why!

And having worked as a cycle mechanic in the past there are plenty of "Numpties" about, one guy came back after Christmas complaining that one of the pedals (LH thread) wouldn't fit and we had spolt his son's Christmas and demanded compensation!

So imagine the confusion with some caravaners, (having read some of the questions some ask!), if we had left and right handed wheel nuts/studs.

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hog, glad you're ok.

you mentioned you recovered the wheel, was there minimal damage to the mounting holes which might indicate a more 'sudden' release or were the holes badly damaged to indicate that the bolts had loosened over a perod of time? also, could there have been an opportunity for someone to tamper with the wheels? I know that sounds like a long shot, but I think I'd almost prefer to beleive that they had been tampered with as opposed to trying to understand what went wrong given all the precautions you had taken.

Thanks for your comments. The holes on the wheel were slightly oval shaped which I assumed meant that they had loosened gradually.

On examination of the wheel, hub and threads the only explanation the dealer good suggest was that maybe someone had tampered with them. I thought at the time that it was a bit of a cop-out as they couldn't give any reason other than it does happen (they estimate about a dozen a year just at their branch). They said most are caused by owners failing to check the torque regularly which is why I am surprised that some think over-checking the bolts may have contributed.

Going back to the sabotage theory I guess there were three opportunities for this but can't imagine why anyone would.

I hitched the van up on my drive the day before we went so it could have been done overnight but this is unlikely in the area we live.

We stayed overnight at the CC club at Dover. Again unlikely on a CC site.

The only other time the van was unattended was on the car deck during the crossing. Again highly unlikely but possible all the same.

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But surely you did check your wheel torque regularaly and your wheel still fell off in fact you seem to check it on every occasion you stopped the van. I check my torque once a year and my wheels have never fallen off, neither I should imagine have 99% of touring caravans. What exactly is the point your trying to make?

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