Torqueing and Checking Wheel Bolts.

[otherclive]

After reading the recent thread where the wheel came off of a caravan and the other wheel nuts were lose I decide to delve a little deeper on what advice is given. And like a lot of things caravan it isn't as straight forward as the advise given to car drivers.

Firstly I looked at all of my caravans previous service sheets. All were carried out by NCC Approved workshops. None showed that either two workshop signatories were involved in the torquing of the wheels, and none showed the Customer being a witness or even signing the worksheets. All however did show the correct torque in the required recording box. Only one from a Swift Main Dealer had any information regarding post servicing checking of the wheel torque. That recommended a recheck after 25 miles approximately, whereas the caravan handbook recommends 15 miles.

Caravan and Motorhome Club recommends a re-check after 20-30 miles or 20-30 minutes driving.
Camping and Caravan Club recommends 50 miles after service.
Wheel Specialist Ltd recommends 30-50 miles.
NCC via an Alko guidance sheet recommends recheck after 20 miles, although looking at the Alko guidance sheets which show an alloy wheel being torqued to 88Nm that should be changed to recommend caravan manufactures specified torque as 88Nm tends to be for steel wheels.
My Swift Sprite Owners Handbook recommends 15 miles approx and the Main Dealer 25 miles.

So what do I conclude from the above? Well a recheck at 25 miles would seem to be a reasonable distance, but that would be going against my own Owners Handbook.

There is widespread agreement within the various sources that I have looked at that checking the wheel torque before each journey is recommended . But WSL advise a further recheck after 30-50 miles into the trip. I must admit I don't do that. But what constitutes a journey/trip? Does 250 miles to Penrith, and after an overnight stop a further 250 miles into the Highlands constitute one or two journeys? Is the return trip part of the overall journey or a new journey? recently after a relatively short trip to Shropshire I did check my wheel torques for the return trip as the roads going were so dire and not just on the near side that I guess I just wanted a bit of comfort. My handbook says that after the post service recheck, further checks should be done regularly.

Then what is a torque check? There are some who advise just using the torque wrench and smoothly applying leverage until it clicks. Whist others advise to loosen the wheel bolt(s) and then retorque. But its not stated whether one should loosen bolts singularly and re torque, or loosen the complete set and retorque.

My own practice is:

1. Ensure that I have seen wheel bolts torqued up at service centre, or do it myself as part of pre departure check. Recheck within 25 miles after service, or wheel replacement.

2. Check wheel torque prior to each journey which normally is outbound and inbound unless fora main holiday where distances are longer when I check outbound and inbound. Shropshire being the exception!

3. Retorque but just applying the torque wrench to the already torqued wheels. I don't loosen bolts/nuts.

4. Give the car wheels a cursory glance for completeness ( A TIC comment)

I bet Ben Hur didnt have such issues when he visited the Forum prior to his trip to the Colliseum :evil:

http://www.caravantimes.co.uk/video/parts/wsl/video-wheel-solutions-explains-how-to-torque-your-caravan-wheel-bolts-$21381952.htm

 

[Thingy]

There is an awful lot to be said in favour of plastic telltales that pop onto the wheel nuts, so during your journey, you can tell at a glance if there is a potential problem. My caravan doesn't have them, but I will be getting a set, issues like this serve as a warning to the rest of us.

http://www.tyre-equipment.co.uk/acatalog/CHECKPOINT_Loose_Wheel_Nut_Indicators.html

 

[Lutz]

And like a lot of things caravan it isn't as straight forward as the advise given to car drivers.

Can you think of any reason why this is so? I don't know of anyone who checks the torque of the wheel bolts on his car other than soon after a wheel change.

 

[Hutch]

There is no point in slackening , wheel bolts/ nuts to do a retorque check, you are effectively, just fitting for the first time, I suppose the use of a fluid such as thread lock or nut lock could give partial peace of mind. Another problem upon retorquing bolts / nut are you should really relieve the weight of the caravan slightly from the wheel so that the bolts can pull the wheel onto the hub face correctly.
A possibility for bolts coming loose could be that the caravan wheel is not balanced causing vibrations. An overtorqued bolt that has been stretched can also be dangerous as the threads are deformed and no longer have the correct profile to grip correctly.
All in all, its a nightmare.

 

[otherclive]

And like a lot of things caravan it isn't as straight forward as the advise given to car drivers.

Can you think of any reason why this is so? I don't know of anyone who checks the torque of the wheel bolts on his car other than soon after a wheel change.

Probably because one is a mainstream industry with millions of users and large development and support budgets and the other still resembles a cottage industry.

 

[otherclive]

There is no point in slackening , wheel bolts/ nuts to do a retorque check, you are effectively, just fitting for the first time, I suppose the use of a fluid such as thread lock or nut lock could give partial peace of mind. Another problem upon retorquing bolts / nut are you should really relieve the weight of the caravan slightly from the wheel so that the bolts can pull the wheel onto the hub face correctly.
A possibility for bolts coming loose could be that the caravan wheel is not balanced causing vibrations. An overtorqued bolt that has been stretched can also be dangerous as the threads are deformed and no longer have the correct profile to grip correctly.
All in all, its a nightmare.

I tend to agree with you on the topic of slackening or non slackening, but there are caravan guidance links out there that recommend slackening. I’ve never slackened Car wheel fastenings either. Neither do I relieve the weight on caravan. It’s bad enough having to retorque so often without the added complication of jacking the caravan up.

 

[Hutch]

I tend to agree with you on the topic of slackening or non slackening, but there are caravan guidance links out there that recommend slackening. I’ve never slackened Car wheel fastenings either. Neither do I relieve the weight on caravan. It’s bad enough having to retorque so often without the added complication of jacking the caravan up.[/quote]

Clive, I mentioned relieving the weight as the correct thing to do. I doubt that not many people do it, myself included, when refitting my wheels after maintenance, I torque the bolts with the weight off the wheel, and retorque after about 10 miles,

 

[Raywood]

I doubt many people retorque their wheels after they have been removed but it is possibly them that is wrong. I cannot see them working loose other than just after refitting though so other than that first check I can find nothing more on the subject.

 

[CustardAvenger]

My own practice is:

1. Ensure that I have seen wheel bolts torqued up at service centre, or do it myself as part of pre departure check. Recheck within 25 miles after service, or wheel replacement.
2. Check wheel torque prior to each journey which normally is outbound and inbound unless fora main holiday where distances are longer when I check outbound and inbound. Shropshire being the exception!
3. Retorque but just applying the torque wrench to the already torqued wheels. I don't loosen bolts/nuts.
4. Give the car wheels a cursory glance for completeness ( A TIC comment)

Hi Clive,

I pretty much have the same routine. The dealer/service location is within 20 miles, so splits the difference; I watched them torque the wheels at hand-over, but can't comment on the service side.

I have always treated the trip as an instance of connecting and disconnecting the caravan to the car. So check the torque just after or before hitching up. What I don't do is check the torque at a rest/comfort stop - perhaps I should.

I also always check the car wheel bolt torque settings, a 10Nm difference, after checking the caravan. I do this after a bad experience with a tyre fitting centre, that didn't properly torque the wheel nuts on one wheel causing a grinding noise after a short distance and ruined at least 5 nuts in addition to causing a stud to shear off due to an over-tight nut - I will never go back to them.

Perhaps what would be best practice would be to slacken off the wheel bolt/nut if you were not the last person to remove the wheel or check torque, as it may have been over-tightened.

Paul.

 

[camel]

One particular well known transport company I worked for would do monthly fleet checks on tyres, when it came to torqueing the wheel nuts up they would torque up the nuts in the normal way leave the wheel for twenty minutes come back and torque up the wheel nuts again and that was it, this procedure came from the truck manufacturer and the tyre company.

 

[Dodger524]

.

 

[Kevin2306]

I check my wheelnuts before each journey, takes minutes and well worth the effort.

Kev

 

[Craigyoung]

Think i'll be investing in some wheel nut markers , even though checked regularly , car and van , never had a wheel overtake me but , I've only ever used the spider bar on the car wheels though , I've never took the van wheels off , but will be investing in a torque wrench also .
Going to check me nuts this weekend when away . :huh:

 

[Perry525]

May I just mention that over 57 years of driving and over 400,000 miles driven, I have torqued my wheels every weekend on my cars/vans. And every time I move my caravan. If I, or someone else has removed a wheel I check it after about a mile. It takes just moments. I have never had a loose wheel nut/bolt in that time. And (horror)! Alloy or steel, they are all torqued to 50 ft lbs.

 

[Craigyoung]

So that works out about 67.8o nm is that right , and some say they are nipping them up into the 12o's ?

 

[Thingy]

There does seem to be quite a few people thinking it pointless to check the torque settings, but there is no smoke without fire. If the industry guidlines suggest it should be done, why on earth would you take the risk and not check. I for one check mine before a long journey, especially if towing ( and I know the length of journey means nothing, its just habit), I always check after car and caravan service and if my wheels have ever been removed, for brakes etc.

Can I point out again that its not just to check the studs/nuts are tight enough, but also that they arent over tight. Tyre fitters especially are dreadfull for just firing away with the airgun and trusting to luck. Simply stating "its never happened to me" is not the way to go. It had never happened to me until my front steer came off and luckily rolled into the ditch at the side of the M1. Not only my life was endangered but everyone else close to me. A lesson hard learned.

It maks sense to think also that if we can't be bothered to check our own, why do we honestly think the mechanics and tyre fitters will do it.

 

[Brasso530]

Perry,do you tighten car and caravan to 50ft lbs? If so more fool you,why bother checking every time you move only to do it incorrectly,manufacturers spend millions on r&d to give you a specific torque,use it.Most new caravan are about 130nm and cars usually between 100 and 140nm.The last time I torqued a wheel to 50ft lbs was a metro.
Thingy,any decent mechanic or tyre fitter should always torque a wheel after removal.

 

[Dustydog]

Where is all this going?
A caravan is a very poor design from a road vehicle point of view and wheel security problems over the last decade are well documented. I said on the other thread most caravanners I know DO check car and caravan with a reliable calibrated torque wr3nch before each journey.
What’s wrong doing that

 

[Thingy]

Thingy,any decent mechanic or tyre fitter should always torque a wheel after removal.

Agreed, but thats a rare and dying breed.

 

[VicMallows]

There has been a lot of discussion about the precise torque applicable according to specification. I seriously wonder about the accuracy and repeatability of the typical wrench , and especially those used by private caravaners. I would personally be amazed if it was better than 10%. I also suspect that precise technique may also be a variable.

I have no idea how a private individual could even go about calibrating their wrench in any cost meaningful way?
(I do not accept that simply checking an already tightened bolt with another so-called 'calibrated' wrench proves anything .... or vise-versa).

How are the wrenches used in a professional situation checked/calibrated? (perhaps Damian can advise?).

I am not in anyway questioning the importance of torquing ..... just the practicality of achieving very precise values.

 

[Damian]

Quote " How are the wrenches used in a professional situation checked/calibrated? (perhaps Damian can advise?)."

My wrenches go away to a certified testing facility every year and come back a week or so later with any adjustments made and a new calibration certificate.
It is not cheap, but essential.
It is surprising just how much they go out of calibration, despite taking precautions to ensure the safe travel from job to job and releasing the tension between uses.

Garages I believe have a mobile testing unit that visits and checks their wrenches.

 

[Grahamh]

It is quite common - seen it loads of times, for tyre fitters to use the airgun to do up the nuts and then put the tq wrench on and just 'click it'. The bolt/nut is already way over torqued before they pick up the torque wrench. Always self check.

 

[Hutch]

In the Aviation trade, A torque wrench it checked against a calibrated Acratorque unit which is set to the torque required and the the torque wrench set to operate / break at that torque. After use the torque wrench is set back to zero. The Acratorque unit is master calibrated every year. I don't know what happens in the caravan or vehicle industry.

 

[Grahamh]

very little I suspect. My point though is no matter how accurate the wrench is it matters not if the bolt/nut is already overtorqed.

 

[CustardAvenger]

So that works out about 67.8o nm is that right , and some say they are nipping them up into the 12o's ?

Craig,

This is from the Swift caravan handbook (2018 version):

"Caravan wheel bolts supplied with your caravan should be tightened to a torque of 88Nm (65lb/ft) on steel wheels or 130Nm (96lb/ft) on alloy wheels and should be checked with the use of a torque wrench regularly..."

My car also has bolts and has a torque setting of 140Nm... my old car which used nuts and studs, dictated 180Nm!

Paul