wheel came off new caravan

[Guest]

Kenneth. re www.boltscience.com/pages/junkertestvideo.htm

With respect, that video shows a set-up that is far removed from a caravan wheel set-up where the wheel is centred and the nut or bolts fit in to Countersunk style hole on the wheel and the wheel is shod with a pneumatic tyres and has sprung suspension and in many cases there is also a shock absorber these days.

 

[Lutz]

Let's face up to the fact that none of us have the answer as to why caravans appear to be more susceptible to wheels coming off than other vehicles.

There are so many factors which can contribute, in whole or in part, to the problem:

1. Incorrect torques applied

2. Vibration characteristics different to those of a car (lack of shock absorbers could play a role here, too)

3. Unsuitable alloy wheels, not up to the job for the axle loads encountered on a caravan (single axle)

4. Chamfer angle of conical nuts or bolt heads not matched with those of the wheel holes

5. Threads greased, resulting in them being overstressed when torque is applied

It could even be a combination of more than one of the above.

Without an in-depth analysis, all we are doing here is surmising, so unless anyone can come up with factual information, we should let the issue rest for the time being.

 

[Dustydog]

I'm going to continue the regular checks.

Thanks for all the thoughts. We could reinvent the wheel soon! LOL!

Cheers

Dustydog

 

[James3]

I would have thought this would be a good subject to hand to Bath University who hae carried out quite a few studies on caravan stability etc.

 

[Entwood]

Have any of the "it's the workshops/mechanics/designers (any one I can blame)" group actually bothered to READ the article posted above ???

http://www.caravanandmotorhomebooks.com/articles/why_wheels_fall_off.html
This is not a new thing .. its been going on for years, and not just on caravans. It is a vibration problem. aircraft have had, for many years, critical componenets "wire locked" to prevent them coming loose. Now, if you want to go the "wire locking" route it will increase your servicing costs, as everything wil take longer and require more facilities, and you will not be able to change a wheel as easily - more tools needed.

The simple act of checking your wheel nuts with a torque wrench takes less than 5 minutes ... and may save you not only a lot of money .. but.. if you want to be overdramatic ... your life.

It is a real world out there .. Newtons Laws cannot be ignored just because you wish it.

 

[Guest]

So where exactly are all these caravans with wheels that fall off?

In tens of thousands of miles of towing our own caravan and with others we know who caravan I've lost one wheel as I was distracted before I'd fully tightened the near side wheel when I got the van off the jack.

Yes, and I know of others who have done the same sort of thing.

Most cases I've heard of occur after the caravan has been worked on. ie - wheel changed, puncture repair, servicing!

Rather than some men in white coats with an array of test rigs and monitors, just engage brain and realise that as reports of wheels dropping of are mainly soon after the wheels have been removed for one of the above. Most cases are caused by human error!

A wheel falling off can lead to expensive damage and insurance claims. A fact of human nature combined with costs and embarrasment is that few are going to admit to customers or loved ones who have been scared witless or an insurerer who will duck out of paying the bill is that somebody 'F***'d' up.

Another issue, if you are so dumb that you dont realise that dirt or rust between a wheel and hubs mating surfaces can lead to the wheel coming loose. Throw away your tools and just let a pro or other competant person work on your wheels!

Also consider that as some caravanners have trouble coping with winding down corner steadies, how good are they at tightening wheel bolts if the have to change a wheel! Age and strength of some caravanners could be another factor especially as many will never have a torque wrench.

 

[Dustydog]

Euro said:

Another issue, if you are so dumb that you dont realise that dirt or rust between a wheel and hubs mating surfaces can lead to the wheel coming loose. Throw away your tools and just let a pro or other competant person work on your wheels!

Short of using a grinder not all corrosion can be easily reomved from the mating surfaces. But then , when did you see anyone do that?? Most of us will use a stiff wire brush but is that sufficient?

Cheers

Dustydog

 

[Guest]

I'm not sure what state you let your hubs and wheels get in Dusty

But if anyone has trouble assesing the threat from rust or dirt for GODS SAKE don't let them loose with a grinder :O)

A hub and wheel would have to have really severe corrosion or a mass of dirt for the wheel and hub not to mate correctly!

If it was bad enough for a wheel to come adrift there is a good chance that the caravan has been maintaind poorly and is not fit for the road

 

[hublock]

No we don't need men with white coats, test rigs and monitors, just an understanding of what's happening.

Then to follow a set of simple procedures to prevent the wheels coming loose.

What "you" personally do is up to you, but to advise others to ignore safe practices, safety checks and the use of torque wrenches is irresponsible.

Vibration WILL cause bolts to unwind as shown in the Junker test. (www.boltscience.com/pages/junkertestvideo.htm)

The thing that prevents the bolts unwinding, even under severe vibration, is the CLAMPING FORCE provided by the fixing bolts.

The CORRECT CENTERING of the wheel and the SEATING of the bolt heads in the conical mounting holes are just as important. The conical holes help to centre the wheel.

The bolts should be tightened in the correct SEQUENCE, and in stages, up to their CORRECT TORQUE SETTING to give an equal loading on each bolt.

In practice there is a high likelihood that the nuts are not perfectly centred in their seats, and the wheels will tend to BED DOWN after a few miles of driving. The tension on each bolt may then be uneven and could result in a dangerous lowering of the clamping force.

The fixing bolts should therefore be checked and re-tensioned after 30 miles of driving.

If not checked the fixing bolts could then continue to loosen due to vibration.

How do you achieve "correct seating/centring of the wheel on the hub"?

First make sure the wheel and hub face and the bolt threads are clean.

With the wheel off the ground, tighten the bolts "finger tight" only. Thump the wheel with the heel of your hand to centre the bolts whilst continuing to tighten the bolts. The wheel can be rotated during this process which will also help to centre the bolts. The final tightening should be done with the wheel on the ground using a torque wrench.

CHECK THE WHEEL BOLTS AFTER 30 MILES OF DRIVING.

I have been involved in two very dangerous situations with wheels coming off, neither were caravans.

1) A bus we were travelling on, where a rear wheel came off and the bus lurched into the curb.

A few miles earlier we had been on the coast road with vertical drops.

2) A car front wheel came off, the car swerved across the motorway from the slow lane towards the central barrier directly in front of us. The car then spun and swerved away just missing us as we passed through a shower of plastic bumpers and other bits and pieces.

Nigel

The information on the Bolt Science page is relevant. (www.boltscience.com/pages/vibloose.htm)

Regards,

 

[xtrailman]

nigel

i have read the article via your link.

it makes for interesting reading.

i noted the use of locktite 290, worth using i would of thought?

second point, he mentioned re-torque again at 100km, so retorque twice, not once, thing is when does the re-torque end?

the third point i picked up on was virtually all is towing was over extreme terrain, of normal roads, and using leaf springs, so not exactly representative of our roads.

still i look forward to buying a new caravan, which i will insist have shock absorbers, a the very least they will reduce the van bouncing so much.

also the wheels i will insist on being balance, to keep gary happy. and also if i secom and buy a pegasus, hopefully stop the walls from falling off?

and finally (this is not a xmas whish list) the caravan must have ATC.

agree with james, wheels falling of to be investigated by bath uni, good idea.

 

[Guest]

Kenneth, who here is advising caravanners not to fit and do up wheels nuts/bolts correctly and tight.

Read back through the posts, I can't see anyone advising against safe practice.

Do the job correctly and wheels don't fall off!

Once again, video at www.boltscience.com/pages/vibloose.htm is a completely different setup to cravan or car wheels and their bolts.

Kenneth

As for you two experiences of others wheels flying off, how do you know that the bus wheel was tightened and fitted correctly?

You Don't! Well that's unless you were there when they put the buss wheels on and knew the torques settings etc.

Unless you saw the wheel that departs from a vehicle, how do yo know that it is not bearing failure and the wheel is still attached to the hub?

That was a commone fault on badly serviced Morris Minor vehicles, and has been a problem with stretch limo imports to europe where the extra length causes bearing failure and the wheel and hub come head off on their own!

The bolt science video show bolts in over sized holes and bad choice of bolts etc for the job in hand. With millions of vehicle on the road I think they have a pretty good setup on wheel bolts providing the Human fitting them does the job correctly!

Human Error is the biggest problem. If not, roads would be littered with bouncing flying wheels and wheel nuts and bolts! 4 or 5 wheel bolts are not all going to depart at the same time so you should be able to find a good supply of bolts along any major highway as well.

 

[hublock]

Hello Euro,

You shout "Do the bl**dy job correctly and wheels don't fall off".

YES THEY DO.

As I stated, if the wheels bed down after fitting the clamping force will be reduced, allowing the bolts to loosen with vibration.

Doing the job correctly should include checking the bolts after 30 miles and tightening to the correct torque figures.

Bolt Science video shows bolts coming loose due to vibration. That is relevant and your just being pedantic.

I do know the nuts on the bus wheel were loose (not the bearings), we heard them rattling round the hub caps but didn't realise until after the wheel overtook us.

I don't know what your rambling on about (how do you know???) why is that relevant. My point is it's not only caravan wheels that come loose, but cars, buses, lorries etc.

Don't get me wrong I don't think this is such a massive problem that we should all panic and start to rethink the design of every vehicle on the road.

My postings have been to find an explanation for Dustydog and Graham (Ponty).

And yes I have seen a front suspension collapse on a Morris Minor, but is it relevant?

Regards,

 

[Guest]

Kenneth, my point is that even if you heard the nuts rattling in your bus wheel, you don't know if they were ever done up correctly in the first place!

Morris Minor point, just to point out that beacuse a wheel comes off a vehicle it doesn't have to have anything to do with wheel bolts coming loose.

I've just been reminded of an uncle who built and indespension trailer using mini wheels. Both the wheels over took him. He'd fitted the weel bearing the wrong way around!

I've yet to find a wheel bolt on alloy or stell wheels that has come loose thirty or so miles after it has been tightened correctly.

Advice re checking wheel bolts a little after refitting is more likely a cover in case of human error rather than vibration problems.

Caravanners have enough worries with some partners concerned about other traffic or snaking or the fact they have a huge box behind them.

Threads such as these can give people the idea that a wheel will pop off any moment and is a regular occurence.

People spould have the peace of mind that if the job is done correctly and checked they will tow for a miilion miles with no chance of a wheel departing.

Come up with a video of a correctly fitted healthy caravan wheel and hub assembly where vibration causes the bolts to come off and the wheel to depart and then you have a real point. Until then the bolt science video is of little use in comaprison to caravan wheels and is scare mongering for some.

 

[James_374408700]

Euro,

I did the job properly and the wheel still nearly fell off.

I have been in engineering for 41 years and know how to tighten and torque bolts etc. IT STILL NEARLY FELL OFF.

There is a problem which I believe to be a combination of soft aluminium alloy and the bedding in of tapered seats etc.

I will not be convinced otherwise. This rarely happened with steel wheels on caravans.

Jim

 

[hublock]

Kenneth, my point is that even if you heard the nuts rattling in your bus wheel, you don't know if they were ever done up correctly in the first place!

Morris Minor point, just to point out that beacuse a wheel comes off a vehicle it doesn't have to have anything to do with wheel bolts coming loose.

I've just been reminded of an uncle who built and indespension trailer using mini wheels. Both the wheels over took him. He'd fitted the weel bearing the wrong way around!

I've yet to find a wheel bolt on alloy or stell wheels that has come loose thirty or so miles after it has been tightened correctly.

Advice re checking wheel bolts a little after refitting is more likely a cover in case of human error rather than vibration problems.

Caravanners have enough worries with some partners concerned about other traffic or snaking or the fact they have a huge box behind them.

Threads such as these can give people the idea that a wheel will pop off any moment and is a regular occurence.

People spould have the peace of mind that if the job is done correctly and checked they will tow for a miilion miles with no chance of a wheel departing.

Come up with a video of a correctly fitted healthy caravan wheel and hub assembly where vibration causes the bolts to come off and the wheel to depart and then you have a real point. Until then the bolt science video is of little use in comaprison to caravan wheels and is scare mongering for some.

Hello Euro,

I'm not sure who to believe you or Bolt Science Ltd., but I'm swaying towards them.

Bolt Science Ltd.

Client List

Our software is in use on five continents - our customers include:

NASA John Deere Inc. Volvo Car Corporation Aeronca Inc. Dupont Inc. JCB Limited Case Corporation General Electric Corporation Inc. Aston Martin Black & Decker Corporation Ford Motor Company Ltd Harley-Davidson Jaguar Cars Limited Beckman Coulter Inc. Land Rover Limited British Petroleum (BP).............. and theres more, lots more.

Euro

"You've yet to find a wheel bolt thats come loose after 30 miles miles or so of being tightened."

Have you ever checked after 30 miles????

You didn't checked the one that fell off.

Checking wheel bolts after 30 miles is a genuine safety issue that should be followed. I have explained why, taking information from the Bolt Science website.

The rest of your posting ...... and your point is??

James

I had a set of Wolfrace alloys in the 1980's they had steel washers which sat in a machined recess of the alloy wheel.

The steel washer had the conical seat for the locking nuts, so they were actually tightened steel on steel.

Do the alloy wheels on caravans have a steel washer or do they fasten directly steel onto alloy.

I'm not sure this would be an issue, but again checking the bolt tension after 30 miles would find any loose bolts due to BEDDING IN.

Regards,

 

[hublock]

Hello Euro,

I'm not sure who to believe you or Bolt Science Ltd., but I'm swaying towards them.

Bolt Science Ltd.

Client List

Our software is in use on five continents - our customers include:

NASA John Deere Inc. Volvo Car Corporation Aeronca Inc. Dupont Inc. JCB Limited Case Corporation General Electric Corporation Inc. Aston Martin Black & Decker Corporation Ford Motor Company Ltd Harley-Davidson Jaguar Cars Limited Beckman Coulter Inc. Land Rover Limited British Petroleum (BP).............. and theres more, lots more.

Euro

"You've yet to find a wheel bolt thats come loose after 30 miles miles or so of being tightened."

Have you ever checked after 30 miles????

You didn't checked the one that fell off.

Checking wheel bolts after 30 miles is a genuine safety issue that should be followed. I have explained why, taking information from the Bolt Science website.

The rest of your posting ...... and your point is??

James

I had a set of Wolfrace alloys in the 1980's they had steel washers which sat in a machined recess of the alloy wheel.

The steel washer had the conical seat for the locking nuts, so they were actually tightened steel on steel.

Do the alloy wheels on caravans have a steel washer or do they fasten directly steel onto alloy.

I'm not sure this would be an issue, but again checking the bolt tension after 30 miles would find any loose bolts due to BEDDING IN.

Regards,

 

[James_374408700]

Kenneth,

They do not have a steel insert and this is my point, this coupled with not having a locating boss on the brake drum I believe is the cause of the problem.

My wheel came loose after having the wheels balanced and having replaced the wheels myself, torqued the bolts and re-checked the torque at 120 miles later, the wheel came loose after travelling some 300 miles later.

There was no possibility of the wheel being tampered with.

The only other thing was that it was quite hot until the weather changed as we went over the Pennines on the A66 and it became very cold. I believe this was a contributing factor.

Jim

 

[Lutz]

Kenneth,

They do not have a steel insert and this is my point, this coupled with not having a locating boss on the brake drum I believe is the cause of the problem.

My wheel came loose after having the wheels balanced and having replaced the wheels myself, torqued the bolts and re-checked the torque at 120 miles later, the wheel came loose after travelling some 300 miles later.

There was no possibility of the wheel being tampered with.

The only other thing was that it was quite hot until the weather changed as we went over the Pennines on the A66 and it became very cold. I believe this was a contributing factor.

Jim

A locating boss is only an assembly aid. Because of necessary clearance between the wheel and the boss, it cannot offer any security in the event of loose wheel nuts.

Changes in ambient temperature will be considerably less than any increase in brake drum temperature during braking, especially on mountain passes. My previous caravan had a brake fade warning buzzer which went on when the brake shoes reached 140

 

[James_374408700]

Lutz,

My thoughts are that the boss/locating device stops undue forces on the wheels bolts/aluminium and are not intended to provide any form of security for bolts that are already loose.

Braking temperature was not an issue. My thoughts are that travelling on Motorways in high temperatures and then encountering a rapid decline in temperature could make matters worse if the Aluminiun seat has not previously "crushed " under the prescribed torque alone?

Jim

 

[emmerson2]

I don't want to tempt Providence here, but in 42 years caravanning, and 50 years driving many thousands of miles, I've never had a wheel come off. Now, I have two theories: 1)I've always done my own maintenance, on both cars and caravans.2) I've never had a vehicle modern enough to have wheel bolts instead of studs and nuts.

My experience also extends to having been a Fleet Engineer on HGVs, including 38 tonne trucks, and don't recall ever using a torque wrench on wheel nuts. We just did them up bl**dy tight.

The same rule applies to my current caravan and my Range Rover. If you do 'em up tight, they won't come off.

"Tight" in this instance means as hard as your foot on the wheelbrace will go!

 

[James_374408700]

I don't want to tempt Providence here, but in 42 years caravanning, and 50 years driving many thousands of miles, I've never had a wheel come off. Now, I have two theories: 1)I've always done my own maintenance, on both cars and caravans.2) I've never had a vehicle modern enough to have wheel bolts instead of studs and nuts.

My experience also extends to having been a Fleet Engineer on HGVs, including 38 tonne trucks, and don't recall ever using a torque wrench on wheel nuts. We just did them up bl**dy tight.

The same rule applies to my current caravan and my Range Rover. If you do 'em up tight, they won't come off.

"Tight" in this instance means as hard as your foot on the wheelbrace will go!

Quite right....but I take it you haven't had alloys on a caravan yet! Jim

 

[Lutz]

Lutz,

My thoughts are that the boss/locating device stops undue forces on the wheels bolts/aluminium and are not intended to provide any form of security for bolts that are already loose.

Braking temperature was not an issue. My thoughts are that travelling on Motorways in high temperatures and then encountering a rapid decline in temperature could make matters worse if the Aluminiun seat has not previously "crushed " under the prescribed torque alone?

Jim

No, the boss, even where present, is not designed to take any load.

My point regarding temperature was that fluctuations in operating temperature of the wheel/brake drum assembly due to braking are much greater than those caused by weather conditions.

 

[James_374408700]

No, the boss, even where present, is not designed to take any load.

My point regarding temperature was that fluctuations in operating temperature of the wheel/brake drum assembly due to braking are much greater than those caused by weather conditions.

Lutz, I take your point about brake temperatures but disagree that a locating boss does not remove some force from the bolts. Jim

 

[DeliDave]

Quite right....but I take it you haven't had alloys on a caravan yet! Jim

long time since I went to school but as aluminium has a higher co-efficient of expansion than steel,if the bolts are tightened to the correct torque and the wheel gets hot in use shouldnt the bolts get tighter in use as the wheel expands more than the bolts.This suggests to me that the bolts are loose through incorrect torqueing,theft attempt or whatever rather than an inherent fault in caravan alloys.Am preparing to be shot down in flames

 

[Lutz]

No, the boss, even where present, is not designed to take any load.

My point regarding temperature was that fluctuations in operating temperature of the wheel/brake drum assembly due to braking are much greater than those caused by weather conditions.

If you take a look at any wheel locating boss you will see that it has at least about a millimeter clearance to the diameter of the hole in the wheel. As such it can't take any load once the wheel nuts are tightened.