Just had to drop one of our mechanics off at A&E after the compressor being used to inflate a tubeless tyre blew the tyre off, breaking his thumb in the process (or it looks as though it has). By 'eck, this never happened when I were a lad using an old hand pump and an inner tube….

Blokes doing lorry tyres often die… powerful stuff compressed air..

What are the other bad things?

shoulda used a track pump.

Isn't that a bad thing about compressors? I have a tubeless setup and I've never used a compressor.

This was a tyre/rim combo resistant to the charms of a track pump unfortunately.

H&S will be after you 🙁

can you reduce the pressure on the compressor? it's not the high pressure that's needed just the flow/volume.

Silly question, but did he control the flow rate at all? Or did he just dump it in big style? I always start slow and keep increasing until it take for just this reason.

The big industrial stuff should by rights be done in cages or water tanks. How many accidents like this before we have to do the same with bike tyres.

I hope he's okay though.

What actually gave way?
The tyre bead or the rim?

Any idea what pressure it went at?

Personally I don't think tubeless tyres are to blame here, perhaps more working practice..
As mentioned already in the car / truck tyre industry these things also happen occasionally with far more severe consequences and accordingly there are well known recommended working practices. It's not like an inflation cage is necessary with cycle tyres but standing back a bit & not holding the rim would seem to be sensible (hindsight is wonderful I know)

fingers don't count as a riddor AFAIR.

ahh ok 🙂

Still got the accident book to do though.

I believe that the tyre popped off at about 40psi. I think this is one of those bad practice things whereby he already knew what he was doing was not the 'right' way. He is a chap who, not learning from the example of others, has become an example for others to heed.

does the ringing in the ears count as RIDDOR?

we have to cage our truck tyres, never blown one yet but the guy sets the pressure connects the air line and back round a corner.. 🙂

is there a way to set your compressor pressure then?

the tyre popped off

What does that mean?
Something should be broken (other than his thumb) – either tyre or rim?

40 psi doesn't sound high…

Truck tyre death is quite horrible.
Fortunately they are quite rare as most tyre fitters are aware of the risk. I recall one case I came across not so long ago though where the tyre had already been mounted and the fitter was remounting the wheel on the trailer when the sidewall ruptured. Dead on the spot poor fecker 🙁

does the ringing in the ears count as RIDDOR?

Ha! I remember once when I was a kid pumping up my bike tyre, got it nice and hard, then suddenly noticed a hole in the tread where I'd been skidding with a bit of innertube poking through. Just reached to let the tyre down when there was an almighty bang that echoed all round the neighbourhood, and my ears rang for ages. So sorry for the poor bloke who had the tyre go while fitting it. That's horrible.

a question here because i genuinely don't understand.

If the bead isn't seated right, thus leading to a blow off and broken thumb – would that be any different with a tubed set up? The pressure being exerted on the sidewall causing the blow off would be the same, no?

I can see that using a pump vs a compressor means the rate of inflation would be less and so the failure might happen at lower pressure, whereas the compressor will have it at 40 in no time at all, but what else am I missing?

depends where the settings where on the compressor. It might have failed because it went well over 40 psi. In that case, tubeless might be safer and the tyre will pop off the rim. With a tube in there, inflated at the same rate but seriously over pressured, you might split the rim. (had that happen on an old Campag mountain bike rim with a track pump. Luckily it was the side facing away from me.

Blimey mtbfix, still not convinced by tubeless eh?! 🙂

I suggest he use a Lezyne minipump in future, like I do to fit my UST tyres.
Or maybe just get him to make the tea instead of touching bikes.

Had this happen to me using a trackpump! 😯

about 40 odd PSI while seating the tyre

no broken fingers thankfully, but had a numb hand for about an hour, was in my garage at the time and was nie on deaf for a good 5-10 mins too
wheel milk went everywhere all over me and sprayed all over the garage ceiling and all

bad tyre/rim combo, 29er Retard Rim with a SmallBlock8 don't try it

Can you get injection injuries at these sorts of psi?

Update: he's torn the tendon, not broken the bones. I suppose a one handed mechanic is not totally useless.

Blimey mtbfix, still not convinced by tubeless eh?!

Not a bit of it. A genius piece of marketing convincing us to use heavier wheel components at the rotating extremity of the wheel. I'll stick to light tyres and tubes at 35psi thanks.

I am still not getting this popping off issue….

A tyre bead is considerably smaller than the rim outer diameter.
Something must have to break? (a tyre bead won't stretch!)
Either the bead of the tyre or the rim no?

He could not get it seated so I presume that it was sitting under the bead and when he blasted the air in the tyre slipped. It is a Hutchinson tyre and IME these go one and come off very easily. One of those things I think.

A genius piece of marketing

I concur if tubeless was SO that much better for off road duties, how can no MX are running on tubeless.
What happen when you pinch flat a tubeless tyre? What happen when the bead pop out of the lip on the rim, what happen when you tear the side wall, what happen when you get a sharp rock to go through the tyre?

I've gone tubeless, and I'm convinced after only a couple of rides.

I concur if tubeless was SO that much better for off road duties, how can no MX are running on tubeless.

Stresses in mx on the tyres are huge compared to mountainbiking- both in cornering and on landings. It doesn't help that the tyres are high profile and squirm a lot more on the rim under acceleration. MX tracks don't have rocks to shred sidewalls.

yeh they do. dirty great flinty rocks.

what happen when you tear the side wall, what happen when you get a sharp rock to go through the tyre?

The air comes out. If the sealant doesn't fix it you stick a tube in.
I've had a sharp rock through the sidewall once in 4 years. Didn't ruin the ride.

What happen when you pinch flat a tubeless tyre?

A pinch is when the tube gets nipped between the tyre and the rim. With no tube, this just isn't going to happen.

What happen when the bead pop out of the lip on the rim?

You lose some or all of the air out of the tyre. If you're running tubes, the tube is going to come out and probably blow itself to bits.

what happen when you tear the side wall?

You patch the sidewall as you would with a tubed setup, and stick a tube in. When you get home you can do a neat patch and go back to tubeless.

what happen when you get a sharp rock to go through the tyre?

See above.

So basically you run a tube in a tubeless tyre… great.
I have seen tyres pinch flat did a horrible noise though.

So basically you run a tube in a tubeless tyre… great.

Except that it almost never happens. 3 months so far with no burps, gashes or anything, including doing the Mega – haven't even topped up the sealant. And that's with a ghetto setup.

What happen when you pinch flat a tubeless tyre?

You get a nasty ding sound from the rim and you carry on riding for the rest of the day. It is only apon looking at video fotoage later that you realise that the rim has hit the ground lots of times that day. 😀

I know someone who was killed instantly when a tractor tyre he was inflating exploded. Probably bad practise, he was only an apprentice. Compressors are dangerous. Not really a valid argument against going tubeless.

Not really a valid argument against going tubeless.

Critically, tubeless was brought to the market after 1996 which means I am inherently suspicious of it as being new-fangled and an unecessary complication. My you should have heard me moan when we went to 9 speed!

I'll stick to light tyres and tubes at 35psi thanks

Please do, I'll stick to my lighter tyres, no tubes at all and the option to run far less pressure, whilst spending less time faffing with punctures.

I forget how many flats I've had since I went tubeless in 2001, fewer than 5.

Daft mechanic update – he's off work now for the week by the sounds of things! Boss ain't happy.

njee20 – I'll let you in on a secret, don't tell anyone, I'd happily try tubeless if I didn't have 5 pairs of part worn normal tyres in the shed. My tight-fistedness far outstrips my luddite tendencies.

Nowt stopping you running normal tyres, even part worn, they may be a bit looser on the rim and require a bit more tape to get a decent seal.

Schwalbe work particularly well, I've got normal Furious Freds to seal with a track pump, and you don't get many tyres lighter than that!

depends what they tyres are. I love my tubeless steups but I've only done two of my bikes so far because the tyres I have left are IRC and Intense, both of which are warned against using for tubless due to a lack of bead strength.