Both the tyre depots I use torque up the wheels as the last action. They use wheelie guns for initial tightening then torque wrench for the final tightening.
Torque wrench for undoing nuts or bolts. Goes contrary to my early training. Why not use the telescopic wrench for wheels and breaker bar for other fastenings.
There have been several threads over the years about caravan wheels coming loose or even fully detaching. Neither situation is good, and can lead to very serious consequences.
In all cases the wheel fastenings were loose, and there were several theories about why this might happen.
Regardless of the reasons, it has been good advice to check the torque on the fastenings after a few miles especially after the wheel has been refitted to avoid the problem.
That advice is not just for caravanner's who have torque wrenches but all caravanner's
In all cases the wheel fastenings were loose, and there were several theories about why this might happen.
Regardless of the reasons, it has been good advice to check the torque on the fastenings after a few miles especially after the wheel has been refitted to avoid the problem.
That advice is not just for caravanner's who have torque wrenches but all caravanner's
I am not disputing anything, but the question is of course why aren't car wheels falling off as I doubt if many motorists carry a torque wrench or even have the wheels re-torqued after the wheels are refitted.
I would think that the hubs on trailer wheels are also used on motor vehicles so there should be no real difference except the car is carrying more weight on the wheels.
Whilst the roads are not littered with discarded wheels, it does happen and if it did, one legitimate question might be "did you check the wheel nut torque, as required in your user manual?". The answer to that question might decide how the next phase of your life goes.
There are several theories about the difference between car and caravan wheel fixings, and as far as I know there hasn't been a definitive explanation. To be fair there haven't been many recent reports, whether that's due to changes that some manufacturers made to the fixings and the advised torque settings , or whether it's down to caravanners heeding the advice and rechecking the fasteners.
It's not a foregone conclusion that trailer hubs are the same as caravan hubs
Do cars carry more weight on their wheels? I suspect that if you do the maths SA caravans may well carry more weight than any tow car wheel, which is why caravan tyres often have a higher load rating.
Logically you are absolutely correct. But the reality is that caravan wheels are commonly reported to come loose. Like Dustydog I have had a detachment. So I regularly check the torque.
When I bought this Lunar new in 2015 I spoke to Lunar who said, that unlike Bailey, they don't have a detachment issue. Now as both makes share a common chassis, that made no sense at all. So, with their permission, I fitted WSL bolts immediatly.
Since then I have not found a loose wheel, but I keep checking because I don’t want that experience ever again.
From this, I deduce that car manufacturers take more care in how the match wheels and bolts and the materials used.
It is also worth noting that Alko use identical hubs for UK and continental vans, but continental vans are machined for 14mm bolts, and only 12mm for the UK.
I highly recommend WSL bolts.
John
Thinking scientifically a 1,500kg caravan is carried mostly one one axle (or two, close together). On a single axle van that's most of the weight (less the nose weight) on two wheels. The tow car is, say, 1,800 kg carried across two widely-spaced axles, so nominally 900 kg per axle (plus the load, including nose weight). The dynamic load will vary on each axle due to acceleration and braking events - a single axle van will not experience this.
Also, caravan wheels tend to be smaller than car wheels, so spin faster for a given road speed.
Car wheels tend to have to accommodate higher lateral loading - a car can corner quite a lot more quickly than a caravan will.
Car wheels have to be able to take acceleration and deceleration torque - a van's wheels only experience braking torque (and, I suspect, nowhere near the maximum braking torque that a car wheel can suffer).
So all-in-all I'd say that the increased load and smaller diameter would be significant factors in determining wheel and tyres specifications and maintenance, but there's no doubt more to it than my top-of-the-head musings.
There is no legal requirement and if the wheel did come off the obviously the service for which you were charged was inadequate and not fit for purpose.
This torquing thing only started because one manufacturer's brand of caravan was losing wheels and it seems only on one side.
I am not disagreeing that it is a good or bad thing to have to re-torque after "x" number of miles for peace of mind, but it should not be necessary.
Bailey got a very bad name for detachments. But as identical chassis are used for most vans where is the logic. It was a Bailey Unicorn that I lost a wheel on. When I had my van fixed I discussed this with the workshop manager at Chipping Sodbury. He showed me a scrapbook he kept of Swift detachments.
It was about that time that Bailey started fitting the WSL bolts, perhaps it was an attempt to clear their name.
I wonder why insurance companies don’t keep stats on detachments, And why UK vans only use 12mm bolts. I believe it is only due to the appearance of the wheels, but it would appear that at some point all UK manufacturers agreed this policy with Alko. There does not seem to be a system which attributes culpability.
John
Your right, it shouldn't be necessary but historically wheel disengagement has been a problem in the past and what's worse, there was no clearly defined cause established. Consequently in teh absence of a guaranteed fix, it simply makes sense to check.
The suggestion is not to have a "retorque" which suggests loosening the fastner and then reapplying the required torque, but to check the torque, which simply means basically testing to see that none of the fasteners have become loose. It's easily done by testing the torque wrench breaks over without the nut moving.
It more akin to checking you've closed all the windows and roof lights rather than opening and closing them again.
Why kick up a fuss about a sensible safety check?
Yes , good point worth raising as I said earlier the consensus amongst us years ago was not to retorque but check the torque of the already fastened bolt /nut.
For the sake of a few seconds it puts my mind at rest to know everything on the wheel front is secure. In the same way , as many others do, once hitched , raise the caravan on the jockey wheel until the car starts to rise. Plenty of detachments have occurred because of incorrect hitching.
For the sake of a few seconds it puts my mind at rest to know everything on the wheel front is secure. In the same way , as many others do, once hitched , raise the caravan on the jockey wheel until the car starts to rise. Plenty of detachments have occurred because of incorrect hitching.
Regarding torque wrenches, 1/2” drive is the correct one BUT you will also need a socket extension so that you can reach the wheel nuts across the wheel offset. Torque wrench on modern van wheels needs to be greater then 150 n/ meters.
Not all van wheels have the same torque spec and requirements.
Not all van wheels have the same torque spec and requirements.
You should always follow the caravan manufacturer's recommendations regarding wheel fastener torque. Do not assume it will be greater than 150NM or any other value. If you don't know the required value check it with the manufacturer's specifications.
Exceeding the specified torque over stretches the fasteners threaded section, and can lead to a reduction in holding force. That is why a torque setting is given, to prevent damage to these safety critical items.
Sorry Prof, in no way was I suggesting that that wheel nuts are whacked up to 150n/m. That figure was to ensure that you buy a wrench with enough capacity to deal with a variety of van and car wheels. Far better, I think, to buy a wrench that will deal with just about most things you can throw at it. Unless your towing with a John Deere or JCB. I have a couple of different wrenches that I use professionally but I think most people would only need one.
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