TRL project into lost wheels.

[Flat in Fifth]

HMG just employed TRL on a project to find out why lorry wheels still keep coming adrift despite all the yellow pointers, nut locking devices etc etc.

Look guys give me a call and I'll tell you.

1) Too low clamping pressure thus wheel shuffle starts, bolt / stud wears, eventually fractures during cornering.
Reasons for too low clamping pressure :-
- a) chimpanzee fitting wheel doesn't use correct torque
- b) as above doesn't clean /oil threads hence lost effort overcoming friction, reduced clamping pressure
- c) old fittings very small window to aim at, newer vehicles have more studs of bigger diameter (by way of explanation)
- d) debris / paint between clamping faces on rims

2) Too high clamping pressure
- see chimpanzee ref 1 a) above
- old fixings see 1 c) above
- driver cracking nuts every morning (ooooh matron)

You can have all the stud locking devices, yellow pointers you like, if the thing hasn't been done up properly in the first place you are stuffed.

HMG you can now sack TRL, please send cheque for inordinate amount of cash to

Villa FiF
2 Letsby Avenue
Nickem on Sea

I'll not hold my breath.

[towman]

The yello pointers don`t work because some of the idiots wh are out there don`t know what they are for.

I caught a new driver moving the pointer the other day because "they don`t line up any more" !

[simpo two]

Locknuts?

[towman]

Threads would be too long.

[pesty]

towman said:

The yello pointers don`t work because some of the idiots wh are out there don`t know what they are for. I caught a new driver moving the pointer the other day because "they don`t line up any more" !

I can well beleive this. there are just far too many fools walking around these days.

Towman. as I beleive you are a truck driver perhaps you can answer this for me.

A few years ago after reading about several deaths that were caused by wheels falling from trucks I wondered why the truck drivers don't carry a torque wrench with them and periodically check/tighten wheels themselves. possibly at the beginning of every journey/ once a week/every 2k miles etc etc.

does this happen, could it happen, any reason why not?
cheers

[Flat in Fifth]

pesty said:

A few years ago after reading about several deaths that were caused by wheels falling from trucks I wondered why the truck drivers don't carry a torque wrench with them and periodically check/tighten wheels themselves. possibly at the beginning of every journey/ once a week/every 2k miles etc etc. does this happen, could it happen, any reason why not? cheers

I can answer this having investigated a number of lost wheel accidents in a former job.

There are a number of reasons for lost wheels as outlined in the original post.

The major problem in my experience is after wheels have been removed for maintenance or tyre/puncture repair.

There has been for some time a Code of Practice to be followed which in short comprises, knowing the correct torque to be used, making sure that there is no soft material eg paint/debris interfering with the clamping faces, stud/bolt threads to be cleaned and oiled, apply correct torque using a torque wrench, then the nuts being checked again by driver after so many miles in case there has been any settlement.

The main problem is with trailers, ie in my experience drivers look after their tractor units, but "nobody owns trailers." By that I mean driver A has a puncture fixed on a trailer, which is then picked up later that day by driver B, who has no idea that the wheel has been changed and the nuts require checking.

Add in the chimpanzee element, a fitter who doesn't know/care and doesn't clean the threads just bangs them "tight" with the air hammer. The problem is that so much friction is lost when the threads are dirty that clamping pressure is reduced.

In the old days when wheel nuts were run up the threads using a spider, you made damn sure the threads were clean because it was hard work otherwise.

To answer your specific question about drivers carrying a torque wrench and checking fixings at regular intervals. One lost wheel incident (actually in this case the vehicle didn't physically become separated from the wheel but vv close) that I was involved with concerned a driver who checked his nuts every morning. He put a long bar on the end of the wrench and bounced on the end until the nuts cracked, by that I mean made that distinctive noise which shows you've shifted them a little bit. What he'd managed to do was increase the stress on the studs little by little until the yield point of the material had been reached, on a corner one of the studs suffered plastic deformation and this placed extra load on the others until another one stretched and away we went.

Hope that explains,

FiF


>> Edited by Flat in Fifth on Monday 5th December 09:42

[Flat in Fifth]

simpo two said:

Locknuts?

Lots of firms supplying locknuts.

The problem is not the nuts working loose, but the wheel shuffling under braking and cornering loads. This causes wear on the studs, which them become overloaded. If you haven'y got the clamping pressure high enough to stop wheel shuffling you could weld the nuts on and you'd still lose wheels.

One firm brought out intelligent studs which was imho a nice solution worthy of further development.

Bit complicated to explain but the stud contained a central core which could be spun realtive to the body of the stud. When the stud was under the correct amount of stress the stud stretched and gripped the loose central core. The idea being that a regular check to see if the central core was loose would determine if the studs were done up tightly enough.

Of course not a cheap solution for an industry which is vv cost conscious, and does demand a driver grovelling round 18 wheels at 4am so not popular there either.

FiF

>> Edited by Flat in Fifth on Monday 5th December 09:49

[gasblaster]

Flat in Fifth said:

I was involved with a driver who checked his nuts every morning. He bounced on the end until the nuts cracked, by that I mean made that distinctive noise which shows you've shifted them a little bit.

Sounds bloody painful but I hope it was good for you too!

[Flat in Fifth]

gasblaster said:

Flat in Fifth said: a misquote but then you knew that Sounds bloody painful but I hope it was good for you too!

btw you mean you don't check your nuts every morning? They're mine and I'll check em as often as I want.

[Code Monkey]

hmm interesting, a thread on threads,

but hasnt this thread been done up before? not sure but all the pointers seem to be there

[pesty]

Thanks Flat.

So it sounds like education is the key. I did say carry a torque wrench in my origonal question which would have stopped the last example you gave if used correctly.
i.e stop turning when it clicks. I see so many people who carry on turning the wrench after the click

anyhow shoult I be cleaning my nuts more often? on my car I mean

>> Edited by pesty on Monday 5th December 11:32

[towman]

pesty said:

I wondered why the truck drivers don't carry a torque wrench with them and periodically check/tighten wheels themselves. possibly at the beginning of every journey/ once a week/every 2k miles etc etc.

Six axles, 10 nuts per wheel = 120 nuts!
Trailers lose wheels far more often that units because of the huge stresses on the wheels. Ever seen an artic doing a "U" turn? The front and rear axles of a triaxle trailer are actually dragged sideways.

[esselte]

Flat in Fifth said:

Villa FiF 2 Letsby Avenue Nickem on Sea

Is that next door to
Miss Mary Lykes
The Dickwell Inn
Tillet
Herts?

[gary_tholl]

Over here, a company came up with a bit of a band-aid solution, which will never be adopted, because it's simple, cheap, and it works.

It's nothing more than a steel strap that runs horizontally around the wheel, about an inch or so bigger than the tire. It's bolted to the frame in front of, and behind the wheel. When (not if) a wheel comes loose, it has nowhere to go, but bounce around a bit inside the cage made by this frame.

They even received special dispensation from Transport Canada that would allow this piece to extend wider than the vehicle maximum (similar to mirrors). This all happened at least 5 years ago, and I still only very seldom see a trailer with them fitted.



>> Edited by gary_tholl on Monday 5th December 20:09

[tvradict]

I threw a couple of wheels from an 8 legger last year. 1st Rear N/S. Had only been at work 2 hours, driven 79km. In the Morning the yellow markers all lined up, 2 hours later 2 wheels rolled past me on the O/S and I found 7 of the 10 nuts scattered up the road. I last had a wheel key on the nuts 4 days before, and the wheels hadn't been taken off for nearly 2 months!

I was told they came off because I hadn't done my checks properly but could offer no explanation to why the nuts has loosened in only 4 days, when they had remained tight for 2 months! Sometimes, nuts just come loose apparently

I dont use a scaffold pole to check them, I dont jump on the bar, I dont crack them everyday, use a bar on them maybe once or twice a week. Whenever I change a wheel I make sure all surfaces (hub and wheels) are clean and I never overtighten wheel nuts!

Haven't changed what I do and haven't lost a wheel since! Go figure!

[Flat in Fifth]

What sort of nuts were they tvradict?

There is actually a design problem with certain types of wheel and fixing design. Bit complicated to explain here, but if the nuts are the ones with a cone to locate into the wheel hole then it can be difficult to get the wheel clamped enough even with the correct procedures in place.