Who really checks their nuts :)?

[Gazbut]

Hi all,
Pick our first van up this Saturday and for weeks I have been watching YouTube videos from the "experts"
One video was saying to check the torque of the wheel nuts before each trip?
Do you guys really do this? Must admit I've never checked my cars and have been driving for 34 years!
Regards
Gazbut

 

[Mel]

Yes before every trip. Caravan wheels seem more prone to falling off than car wheels.
Mel

 

[DaveA1]

Yes before the start of a trip, rarely during the trip. Check car nuts after about 30 miles after a wheel as been removed, then I never bother again. Check my third set of nuts every six months or so. :silly: :silly:

 

[Hutch]

I check the Nuts / bolts on the caravan wheels, before I set off from my drive way, as on a previous thread someone had a wheel depart their caravan , the thoughts were that someone, loosened the bolts, deliberately

But on site or from storage I don't bother. .

 

[Damian]

Hi all,
Pick our first van up this Saturday and for weeks I have been watching YouTube videos from the "experts"
One video was saying to check the torque of the wheel nuts before each trip?
Do you guys really do this? Must admit I've never checked my cars and have been driving for 34 years!
Regards
Gazbut

It is no good comparing car wheel nuts to caravan wheelnuts, there are subtle differences between the two and how they perform.
Car axles where the wheel is mounted have a central spigot which helps place the wheel in exactly the right place and forms a kind of lock.
Caravan brake drums do not have this spigot which means the wheel can be not sitting correctly when fitted and will allow the wheel to move under certain conditions resulting in losing a wheel, normally the nearside one.

You may mock "experts" but their advice is based on well documented real life experience and the results.

As with most things you can choose to ignore this advice but then don't be surprised when you become a victim of one wheel disappearing down the road on its own and your van seriously damaged .,

 

[CustardAvenger]

My routine is to check the torque before every "trip". That is to say every time the caravan is hitched to the car.
I also slacken-off and re-torque if the wheels have been removed by a 3rd Party (i.e. the dealer), then re-torque again after a distance or before the next trip (I only live about 20 miles from my dealer).

I also torque the wheel bolts on my car too... part of my routine was formed by a bad experience after the car's tyres were replaced. One wheel was so poorly bolted it squeaked when the car was driven (yes, I should have checked them myself, but had forgotten, so lesson learned). The other was over-torqued and snapped one the studs when I tried to slacken off the nut... I also required 4 nuts to be replaced as they had been stripped. Never going back to that tyre fitter.

 

[Gazbut]

Thanks Damian and everyone else.,

Certainly no mocking of "experts" intended at all; in fact quite the opposite. I spend my life researching things on YouTube and places like this before any purchase.
I put massive value in information and instruction from kind people who make no financial gain from offering their experience and advice.
Thanks again
Gazbut

 

[chrisn7]

Milenco do a set of plastic caps with an arrow shape cut out, that you just press them onto the wheel nut. Works on the same principle as those yellow ones you see on buses and trucks. A simple visual is all that is needed, a lot quicker than getting torque wrench and locking wheel nut key out to check 20 nuts on a TA..

 

[ProfJohnL]

Milenco do a set of plastic caps with an arrow shape cut out, that you just press them onto the wheel nut. Works on the same principle as those yellow ones you see on buses and trucks. A simple visual is all that is needed, a lot quicker than getting torque wrench and locking wheel nut key out to check 20 nuts on a TA..

The pastic markers will only confirm is a nut or pin has rotated from its set position. It will not show if something else has relived the clampng pressure. Such devices are not a a subsitute for rechecking the torque.

 

[JTQ]

Milenco do a set of plastic caps with an arrow shape cut out, that you just press them onto the wheel nut. Works on the same principle as those yellow ones you see on buses and trucks. A simple visual is all that is needed, a lot quicker than getting torque wrench and locking wheel nut key out to check 20 nuts on a TA..

The pastic markers will only confirm is a nut or pin has rotated from its set position. It will not show if something else has relived the clampng pressure. Such devices are not a a subsitute for rechecking the torque.

Exactly.
The vital securing tension in the bolts that creates the friction so the wheel does not come off, can be lost well before any of the bolts ever turn. Here there are a number of surfaces that can "settle" and with it the tension and friction leach away.

 

[Lutz]

I only check the torques immediately after the wheels have been fitted, of course, and again when they've done a few miles of towing, the same as I would with my car. It's a practice that I have followed after almost 30 years of caravanning.
Actually, the second check never revealed that there was a loss of torque. It was just a safety measure.

 

[chrisn7]

But the nut or bolt has turn before a wheel can fall off. And why is it ok for HGVs to have them then?

 

[ProfJohnL]

But the nut or bolt has turn before a wheel can fall off. And why is it ok for HGVs to have them then?

What you have written here is correct in so far for a wheel to fall off, all the nuts or studs would have to release completely and thatt would require them to unscrew and would be diclosed by the arrows.

But the point being made previously is about the situation if someone has not properly cleaned the rim before refitting it to teh stubaxle, and ther mights be some forign object (grit or rust/corrosion) which gets trapped in the joint. When the fixings are tightened, the rim is clamped to eth stub, but the trapped debris prevents the rim from completely sitting tight of the hub even though the correct torque has been applied.

When torquing a fixing the process tensions and stretches the fixing to produce a clamping force. Wheel fixings for example may be stretched by 0.2mm or there abouts whne correctly torqued.(the actual amount depends on the size of the fixing , the material and the torque) If some debris (say 0.05mm) is in between the two parts being clampded the debris holds the surfaces apart by that amount.

If when driven the debris break up and becomes much smaller particles the tension in the bolt will pull teh two prts closer together but with less than the desired force, but cruishally the nuts will not have rotated to do this, but the system is now under torqued.

Thre are other ways this can happen, for example even if a wheel is correctly refitted, if the wheel when in motion becomes over heated the materials will expand and if the temeprature change is enough, it could permananely stretch teh fixing bolts such that when it cools down, the clamping force is reduced becasue the bolt has been taken past its elastic limit.

The marketrs used on HGV's and some caravans do not indicate if a fixing has been correctly torqued, they will only indicate if the hexagon has rotated, by which time all clamping force will have been severly reduced or losts on that particular fixing.

May I bring your attentio to this
http://www.boltscience.com/pages/failure4.htm
Check thedescriptio on the picure at the bottom of page 1.

 

[steve2019]

Gazbut

It is no good comparing car wheel nuts to caravan wheelnuts, there are subtle differences between the two and how they perform.
Car axles where the wheel is mounted have a central spigot which helps place the wheel in exactly the right place and forms a kind of lock.
Caravan brake drums do not have this spigot which means the wheel can be not sitting correctly when fitted and will allow the wheel to move under certain conditions resulting in losing a wheel...... .,

The main problem here is getting the wheel centralized on the hub, when there is no central flange to hold the wheel in the centre people will often do the first wheel nut tight before centralizing the wheel with the remaining nuts, and because the first nut is clamping the wheel to the hub it cannot move to allow the remaining nuts to sit nicely in the tapered recess, (hope that makes sense)
The correct way to do this would be to gradually tighten each nut a bit at a time (in an opposite sequence, eg: north, then south, then west and finally east) until all 4 or 5 nuts are at the correct torque.
I have never seen a wheel come loose from an uncalibrated torque wrench by the way, its always because the wheel was not fitted correctly in the first place. If the wheel is tight coming off or on the hub with the wheel nuts removed then sonething needs cleaning up.

 

[JTQ]

Gazbut

It is no good comparing car wheel nuts to caravan wheelnuts, there are subtle differences between the two and how they perform.
Car axles where the wheel is mounted have a central spigot which helps place the wheel in exactly the right place and forms a kind of lock.
Caravan brake drums do not have this spigot which means the wheel can be not sitting correctly when fitted and will allow the wheel to move under certain conditions resulting in losing a wheel...... .,

The main problem here is getting the wheel centralized on the hub, when there is no central flange to hold the wheel in the centre people will often do the first wheel nut tight before centralizing the wheel with the remaining nuts, and because the first nut is clamping the wheel to the hub it cannot move to allow the remaining nuts to sit nicely in the tapered recess, (hope that makes sense)
The correct way to do this would be to gradually tighten each nut a bit at a time (in an opposite sequence, eg: north, then south, then west and finally east) until all 4 or 5 nuts are at the correct torque.
I have never seen a wheel come loose from an uncalibrated torque wrench by the way, its always because the wheel was not fitted correctly in the first place. If the wheel is tight coming off or on the hub with the wheel nuts removed then sonething needs cleaning up.

I like to take a minimum physical effort approach with centreing up wheels.
When putting a wheel back, as the bolting is a pentagon pattern, I just insert finger tight a bolt in any available hole, then rotate wheel to bring this up to the top, with the wheel hanging on that bolt. This then offers the two base bolt holes of the pentagon to readily finger tighten those two bolts in place. Then take wrench and lightly tighen all three allowing their centreing cones or spheres [Alloy & Steel wheels respectively is the general convention here] to do the job of just raising the wheel off the top bolts shank. Then the other two bolts go in and I do a light tightening in the cross diameter fashion. Lower off jack then again fully tighten diametrically. I do it the same with spigotted hubs as the spigot on European trailers and cars where used, is not a precision centreing feature, still the bolts do the centring. If the spigot was tight enough to do much more that approximately centre to get the bolts in, then it would be far too tight to remove a wheel by the road side without extraction kit. Some centreing is done simply with a plastic ring insert, just a guide that takes the wheels weight as my top bolt does with non spigotted hubs.