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
Deli-dave,
Quite right, I think that when the wheel is new and then gets hot the alloy compresses and when it cools you have a loose bolt. Once this process has happened then things are OK after re-tightening. This has been the situation in my case. But this is my opinion and as you say I will get ready to be shot down!
Cheers Jim
Quite right, I think that when the wheel is new and then gets hot the alloy compresses and when it cools you have a loose bolt. Once this process has happened then things are OK after re-tightening. This has been the situation in my case. But this is my opinion and as you say I will get ready to be shot down!
Cheers Jim
Taking into account the wall thickness of the aluminium in the area of the wheel nuts, I suspect that the actual thermal expansion of the alumnium is less than the material flow due to the pressure of the tightened wheel nuts.
Besides, if temperature were a really significant contributing factor towards wheels coming adrift, we would be seeing cars losing wheels left right and centre during our travels.
I cant counter that,expansion of aluminium is twice that of steel more or less according to site I checked on but you would imagine that after say 30 miles travel then checking torque you would be OK.Have had 3 vans with alloys and they are still on so far touch wood,but I have every sympathy with someone who has lost a wheel,whether its the dealer,designer, manufacturer or owner to blame doesnt lessen the trauma.Just hope it doesnt happen to me.Incidentally I have never checked the torque so far but I think I really will in future after following this thread
Deli-dave,
I can't understand how people lose a wheel completely. Trust me you will hear it before it comes off unless you are hard of hearing!
Jim
I can't understand how people lose a wheel completely. Trust me you will hear it before it comes off unless you are hard of hearing!
Jim
Kenneth.
In my case a thirty mile check would not have been a lot of good! My mistake was many years ago, my children were young I had the caravan jacked up and had serviced the brakes and wheel bearings and adjusted the hand brake etc.
I tightened the wheels firmly before taking the van off the jack, I then torqued the wheels on the off side and then got called away by one of my children to help my wife as we were on a tight schedule and hada ferry to catch.
My mistake, for once I never went back and rechecked. The wheel came off on route to the ferry about two miles from departure!
My mistake, my human error. I have the honesty to stand up and admit that.
I didn't want my wife and children thinking that a wheel could pop off at any time, we'd not been over 25mph between leaving and when it came off and were actually pulling away from lights. I owned up as I realised my mistake!
What has Bolt Sciences client list got to do with wheels falling off? There are lots of nuts and bolts on cars, and you have no idea what they use the Software for! Is it wheels and hubs and wheel bolts?
If you search the Bolt Science site re wheels, it gives most case of wheel problems linked to stud faiure caused by fatigue, there is also mention of incorrect tightening. And they seem to to say that the main problems are with HGV not cars or caravan wheels, no mention of dissapearing caravan wheels.
My point from many weeks ago is that you do the wheels bolts up correctly and you dont't have wheels falling off.
Modern Alloy wheels are harder and stronger than years ago and modern manufacturing processes and the alloy mixes used are less porous.
I believe that caravan alloys are made by major manufactureres of car alloys and to the same exacting standards. If a caravan wheel has a "soft" bolt seating allowing bolts to loosen we believe the wheel has a fault.
My F1 engineer brother will tell you that in all his years of car building and racing, parts drop of due to human failure virtually every time. Teams may not admit that in public but that's the fact! And they don't have time to stop and do up there one bolt on a race car wheel after 30 miles, they either do the job correctly or they have wheels bouncing in to the crowds or marshall or other drivers.
In my case a thirty mile check would not have been a lot of good! My mistake was many years ago, my children were young I had the caravan jacked up and had serviced the brakes and wheel bearings and adjusted the hand brake etc.
I tightened the wheels firmly before taking the van off the jack, I then torqued the wheels on the off side and then got called away by one of my children to help my wife as we were on a tight schedule and hada ferry to catch.
My mistake, for once I never went back and rechecked. The wheel came off on route to the ferry about two miles from departure!
My mistake, my human error. I have the honesty to stand up and admit that.
I didn't want my wife and children thinking that a wheel could pop off at any time, we'd not been over 25mph between leaving and when it came off and were actually pulling away from lights. I owned up as I realised my mistake!
What has Bolt Sciences client list got to do with wheels falling off? There are lots of nuts and bolts on cars, and you have no idea what they use the Software for! Is it wheels and hubs and wheel bolts?
If you search the Bolt Science site re wheels, it gives most case of wheel problems linked to stud faiure caused by fatigue, there is also mention of incorrect tightening. And they seem to to say that the main problems are with HGV not cars or caravan wheels, no mention of dissapearing caravan wheels.
My point from many weeks ago is that you do the wheels bolts up correctly and you dont't have wheels falling off.
Modern Alloy wheels are harder and stronger than years ago and modern manufacturing processes and the alloy mixes used are less porous.
I believe that caravan alloys are made by major manufactureres of car alloys and to the same exacting standards. If a caravan wheel has a "soft" bolt seating allowing bolts to loosen we believe the wheel has a fault.
My F1 engineer brother will tell you that in all his years of car building and racing, parts drop of due to human failure virtually every time. Teams may not admit that in public but that's the fact! And they don't have time to stop and do up there one bolt on a race car wheel after 30 miles, they either do the job correctly or they have wheels bouncing in to the crowds or marshall or other drivers.
Do some wheels come off? - Yes
Do we have conclusive evidence of the cause(s)? - No
Does anyone have the correct and universal answer? - No
Do we have conclusive evidence of the cause(s)? - No
Does anyone have the correct and universal answer? - No
This topic reminds me of an accident I attended in my capacity as a HGV recovery mechanic 10 years ago,a young woman took her car into a well known tyre dealership in Cumbria and had 4 new tyres fitted, she picked the car up and left the depot on a wet stormy dark evening and 3 miles down the road she had an accident with a motorcycle that made a right turn across her path, she braked hard but collided with the old boy on the bike, he suffered crippling injuries, and I was called by the police and recovered both vehicles and at the polices request both vehicles were taken to my workshops and an Accident Investigation Officer checked them over. He found that neither vehicle had any mechanical defects and in fact found the woman's elderly car was in very good condition and well maintained for its age... BUT...the 2 front tyre pressures should have been 30, they were in fact inflated to 45, this was a major contributor to the accident as the over inflated tyres skated and failed to grip the wet road and pull the car up in time. In the following investigation, the tyre dealer admitted an employee had in error during a very busy workload period over-inflated the 2 front tyres and as such the garage was heavily fined and new working procedures and practices applied, they were named shamed in the press, the young woman however, was charged with having a vehicle on the public highway in a dangerous condition and she was also fined and had penalty points applied because.... "Although it was primarily the fault of the garage for over-inflating the tyres, it was also the duty of the driver of the vehicle to check the tyre pressures and wheel nuts were tight and to her satisfaction and within manufacturers spec before she took the vehicle on the public highway." I heard later that she sold the car, never drove again and employed a solicitor to sue the garage but I dont know what became of it except that there's a lesson to be learn't from it. Check your wheel nuts and tyre pressures on a regular basis and especially when someone else has been working on your wheels.
James, neither my car nor my wife's car has a locating boss on the hub of the rear axle, only on the front.
Euro, I still suspect that there are caravans out there with substandard alloy wheels. Caravan manufacturers, simply by virtue of their size, do not have the resources to develop their own specifications for wheels and have to rely on what is offered to them. Large car manufacturers, on the other hand, can afford to have more than one engineer, responsible for wheel development and test only. As such, I could imagine that at least some of the alloy wheels found on caravans originate from some Chinese backstreet joint without adequate quality control.
John,
I couldn't agree more.
The thing that winds me up is there seems to be an inference that as an owner that this has happened to, it is my fault.
Jim
I couldn't agree more.
The thing that winds me up is there seems to be an inference that as an owner that this has happened to, it is my fault.
Jim
John L eloquentlt concluded:-
Do some wheels come off? - Yes
Do we have conclusive evidence of the cause(s)? - No
Does anyone have the correct and universal answer? - No
Four people have had the problem, not a lot but one is too many.
It took me 39 years before it happened. I really don't care who says what but I know for a fact double checking as recommended will avoid , I hope , a repetition.
I'd like to know why all the caravan dealers and tyre suppliers tell you to retorque the wheel nuts /bolts after 30 or 50 miles??? They don't say that for fun do they ??
Cheers
Dustydog
Do some wheels come off? - Yes
Do we have conclusive evidence of the cause(s)? - No
Does anyone have the correct and universal answer? - No
Four people have had the problem, not a lot but one is too many.
It took me 39 years before it happened. I really don't care who says what but I know for a fact double checking as recommended will avoid , I hope , a repetition.
I'd like to know why all the caravan dealers and tyre suppliers tell you to retorque the wheel nuts /bolts after 30 or 50 miles??? They don't say that for fun do they ??
Cheers
Dustydog
Hi Dustydog,
I think the problem is much more widespread than this forum shows.
I know of 2 experienced vanners that this has happened to this year on new vans, neither of them contribute to the forum.
Jim
I think the problem is much more widespread than this forum shows.
I know of 2 experienced vanners that this has happened to this year on new vans, neither of them contribute to the forum.
Jim
When I had new tyres fitted to my caravan, the fitter was very surprised there wasn't a ring around the hub to locate the wheel. He said without the locating ring, the whole of the caravan weight was being held by the sideways forces on the bolts - which he thought was unusual and dangerous. If the wheel moves even a fraction as it rotates, the nearside wheel will quickly become loose.
If this were a car, I think VOSA would be interested in a recall.
I think that anyone who has had this happen should try the courts - I don't think the design is fit for purpose, and the advice about retorquing is inadequate.
I'm a Chartered Engineer, and I'd never release a design which was this poor.
If this were a car, I think VOSA would be interested in a recall.
I think that anyone who has had this happen should try the courts - I don't think the design is fit for purpose, and the advice about retorquing is inadequate.
I'm a Chartered Engineer, and I'd never release a design which was this poor.
Without a spigot ring, the wheels are located by tapers in the wheel rim, and on the wheel bolts. Now if you have 5 tapers, what is the chance that the hub can be machined accurately enough to alllow proper 360 annular contact at each taper - just about nil!
As the tapers locate the wheel, they take some load as the wheel rotates - the wheel will move around, promoting wheel nut loosening.
If this sounds far fetched, remember doing up the bolt is only stretching it by about 30 microns - so imperfections in the wheel could be a contributory factor.
What to do about it if this is one of the causes? If you have problems with the nearside wheel coming loose (it will generally be the nearside) try swapping the two wheels over - the other wheel might be slightly better machined!
But ... I'm much prefer to see a better engineered solution!
As the tapers locate the wheel, they take some load as the wheel rotates - the wheel will move around, promoting wheel nut loosening.
If this sounds far fetched, remember doing up the bolt is only stretching it by about 30 microns - so imperfections in the wheel could be a contributory factor.
What to do about it if this is one of the causes? If you have problems with the nearside wheel coming loose (it will generally be the nearside) try swapping the two wheels over - the other wheel might be slightly better machined!
But ... I'm much prefer to see a better engineered solution!
Please refer to my previous replies regarding locating rings. In short, cars don't have them across the board, either. Secondly, they can only serve as assembly aids because of the necessary clearance (for build tolerance reasons) between the ring and the inside diameter of the central hole in the wheel. They do not support any weight once the wheel nuts are tightened.
I still think its time for some research then to find out the cause(s). This will only happen if the caravan makers (and hence the chassis makers) are put to financial penalty.
I think this would be a useful thing to refer to the researchers at Bath.
Or alternatively, just put left hand bolts on the nearside - they will not be prone to coming undone in the same way.
I think this would be a useful thing to refer to the researchers at Bath.
Or alternatively, just put left hand bolts on the nearside - they will not be prone to coming undone in the same way.
I'd suggest that the insurance companies be in the boat, too. After all, they've got to cover the cost of any claims as a result of wheels coming off. They've probably also got more financial resources available for such an investigation than many caravan manufacturers.
the boss in my experience, does nothing to support the wheel, if you look very close, there is a clearance, the wheel is not actually in contact with the boss.
Lost wheel syndrome has been happening for as long as i can remember,and i can remember the last 30years in the transport business,My own fathers fleet of leylands and bedfords suffered.Times long now gone,but back then they used left hand threads ie n/s tighten to the front.Had no effect.
The then ministry of transport looked into it,before deciding to prosicute the operator.
Dead simple-clean faces,oiled threads,good spigots,no oval holes,torqued to correct figure with a torque wrench,and not over tightened as this is just as bad,re-torque after 30 mins.
The then ministry of transport looked into it,before deciding to prosicute the operator.
Dead simple-clean faces,oiled threads,good spigots,no oval holes,torqued to correct figure with a torque wrench,and not over tightened as this is just as bad,re-torque after 30 mins.
Lutz I believe that UK caravan manufacturers sourced wheels from the likes of www.tyreline.com / Rimstock / Alcoa / as per Dynamics wheels. If they are launchng thousands of
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