A cautionary tale

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whimsical ninja

Original Poster:

164 posts

29 months

Sunday 7th August 2022
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In a month and a location that will remain nameless, there was an emergency services driver. That driver was me.

When I took the car out I had a low tyre pressure warning. One of the tyres was down about 5-6 psi lower than the others. Low, I thought, but not dramatically low. I filled it up to proper pressure, had a good look at the tyre, could see nothing out of the ordinary, and thought "It'll probably be fine."

I then went on an extended blue light run. Long story short: that same tyre blew out at 120mph on a motorway. I instantly lost all control. Somehow - and it's testament to how well made modern cars are made - my passenger and I walked away uninjured. Car is completely written off, needless to say.

Two lessons which I think are worth repeating:

1. Your daily inspection of the car isn't optional. As blue light drivers it can sometimes be something we think "we do this because a stupid policy says so". No. It takes 2 minutes and it literally just checking the essential safety features - tyres, brakes, lights. Dashboard warning lights aren't an irritation, they're a life saver, blue light driver or not.
2. "It'll probably be fine"...just isn't a thing. It probably won't be fine. And for the non-blue light drivers out there, you might think "well it's cos you were at 120mph". We got exceptionally lucky but even at 70mph it would have been terrifying and potentially life-changing. If you're in any doubt about the roadworthiness of your car and you're doing anything other than slow urban driving, get it looked at sooner rather than later.

Life goes on...

Edited by whimsical ninja on Sunday 7th August 19:28


Edited by whimsical ninja on Sunday 7th August 19:29

Pica-Pica

14,029 posts

86 months

Sunday 7th August 2022
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Some questions:
Can you describe ‘blew out’ ?
Did the tyre leave the rim?
Would run-flats have helped?

911hope

2,773 posts

28 months

Sunday 7th August 2022
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whimsical ninja said:
In a month and a location that will remain nameless, there was an emergency services driver. That driver was me.

When I took the car out I had a low tyre pressure warning. One of the tyres was down about 5-6 psi lower than the others. Low, I thought, but not dramatically low. I filled it up to proper pressure, had a good look at the tyre, could see nothing out of the ordinary, and thought "It'll probably be fine."

I then went on an extended blue light run. Long story short: that same tyre blew out at 120mph on a motorway. I instantly lost all control. Somehow - and it's testament to how well made modern cars are made - my passenger and I walked away uninjured. Car is completely written off, needless to say.

Two lessons which I think are worth repeating:

1. Your daily inspection of the car isn't optional. As blue light drivers it can sometimes be something we think "we do this because a stupid policy says so". No. It takes 2 minutes and it literally just checking the essential safety features - tyres, brakes, lights. Dashboard warning lights aren't an irritation, they're a life saver, blue light driver or not.
2. "It'll probably be fine"...just isn't a thing. It probably won't be fine. And for the non-blue light drivers out there, you might think "well it's cos you were at 120mph". We got exceptionally lucky but even at 70mph it would have been terrifying and potentially life-changing. If you're in any doubt about the roadworthiness of your car and you're doing anything other than slow urban driving, get it looked at sooner rather than later.

Life goes on...
What I'd like to know is...what sort of car protects it's occupants the this degree in a 120mph crash?

That is about 3x the energy of a car at 70mpg.

I think we should all get one.

whimsical ninja

Original Poster:

164 posts

29 months

Sunday 7th August 2022
quotequote all
All fair questions. It wasn't a head-on - if it was I wouldn't be here to post this. The central reservation did its job in slowing the car down - we were mostly dragged along it. The only airbag to go off was the driver's side one.

Tyre certainly left the rim but my technical know-how isn't good enough to know about run-flats. In terms of what happened, I don't know - there was no degradation of the handling until it happened, which was (or felt) instantaneous.


Zarco

18,061 posts

211 months

Monday 8th August 2022
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I think even run flats would over heat and fail when run flat at 120mph.

They are designed to get you home at reduced speed.

larrylamb11

597 posts

253 months

Monday 8th August 2022
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I wonder if this was a sudden deflation as a result of the loss of a foreign object?
There is a reasonable possibility that the tyre showing the low pressure on the monitoring had been punctured by a foreign object that was still in the tread, something like a screw or nail... which then departed as speed rose and led to a rapid deflation. I've had exactly this situation myself and (years ago) even heard the object hit the inside of the wheelarch as it departed the tyre tread, following which the tyre instantly deflated.

Potential mitigation in your situation might have included a visual inspection of the entire tyre tread on the tyre with the low pressure before starting the shift. The TPMS had already warned there was a problem with that tyre, if re-inflation had been accompanied with a proper visual inspection it may have been possible to avoid the failure. Also entirely possible that none of that is relevant and you were just plain unlucky! Either way, glad to hear the outcome didn't involve any injuries - the car did it's job at the end of the day.

Solocle

3,384 posts

86 months

Monday 8th August 2022
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larrylamb11 said:
I wonder if this was a sudden deflation as a result of the loss of a foreign object?
There is a reasonable possibility that the tyre showing the low pressure on the monitoring had been punctured by a foreign object that was still in the tread, something like a screw or nail... which then departed as speed rose and led to a rapid deflation. I've had exactly this situation myself and (years ago) even heard the object hit the inside of the wheelarch as it departed the tyre tread, following which the tyre instantly deflated.

Potential mitigation in your situation might have included a visual inspection of the entire tyre tread on the tyre with the low pressure before starting the shift. The TPMS had already warned there was a problem with that tyre, if re-inflation had been accompanied with a proper visual inspection it may have been possible to avoid the failure. Also entirely possible that none of that is relevant and you were just plain unlucky! Either way, glad to hear the outcome didn't involve any injuries - the car did it's job at the end of the day.
Yep - of course it could also be something like damage to the inner carcass - but such a defect could be accompanied by a bubble.

georgeyboy12345

3,574 posts

37 months

Monday 8th August 2022
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So, say you go out in a car again in a few weeks, you get a TPMS warning and you find one of the tyres is 6 psi lower than the others. What will you do?

Rat Park Refugee

7 posts

22 months

Wednesday 10th August 2022
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Sorry forgive me if I'm being thick but what's the point of this story? You went to drive, saw a low pressure warning, blew the tyre up to its recommended pressure, and then had a blow-out? what are we supposed to do, not inflate such a tyre? if we ever get a low pressure warning never drive at 120mph until we get the tyre replaced? or have I misread?

Zarco

18,061 posts

211 months

Wednesday 10th August 2022
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Rat Park Refugee said:
Sorry forgive me if I'm being thick but what's the point of this story? You went to drive, saw a low pressure warning, blew the tyre up to its recommended pressure, and then had a blow-out? what are we supposed to do, not inflate such a tyre? if we ever get a low pressure warning never drive at 120mph until we get the tyre replaced? or have I misread?
hehe

Does rather seem to be 'don't ignore obvious warning'.

FiF

44,408 posts

253 months

Wednesday 10th August 2022
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I think some of are being somewhat harsh on the OP. They clearly stated they "had a good look at the tyre" before going out.

So taking that at face value it's possible to assume that there was no obvious cause to identify the reason for the pressure loss.

The vehicle was fitted with TPMS so again is it reasonable to assume (yes I know) that from start of shift to commencement of blue light run the TPMS had not triggered a warning.

So what was the cause? Was it a fault? Was it an unrelated piece of debris causing instant deflation and problem? We and you don't know, with respect.

What could have been done differently? Easy to say, depending on the time between start of shift and sorting out the pressures, was there time for an independent pressure check in case there was still pressure loss but insufficient to trigger TPMS? Easy to say, less easy to do under job pressures.

Putting another slant on things, piece of electrical kit stops working. Oh it's just the fuse. How many of use just change the fuse and carry on, yet the fuse blew for a reason.


Pistom

5,102 posts

161 months

Wednesday 10th August 2022
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I'm a little taken aback by some of the responses to this thread.

As I see it, it's someone who has been in a potentially life threatening incident, possibly even writing this whilst under the influence of shock and sharing their thoughts.

Sounds like he did what any other reasonable person would have done and in fairness, doesn't even know if the slight low pressure was related to the later incident.

I assume their here to tell the tale as a lot of speed got scrubbed off before hitting anything.

So what do we do as a result of this tale? Make sure you check the condition of your car regularly and don't drive around with the attitude of "it will be alright".

Reasonable advice which I imagine most of us will ignore.

Glad OP seems to have suffered little if anything more than a bit of a shakeup.

BertBert

19,174 posts

213 months

Wednesday 10th August 2022
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sounds like a perfectly sensible cautionary tale to me - thanks to the OP for posting.

whimsical ninja

Original Poster:

164 posts

29 months

Wednesday 10th August 2022
quotequote all
I suppose the point is, firstly check your tyre pressures daily, manually. I don't want to rely on a single electronic system. Also some TPMS don't give you an absolute value but rather give a warning when value is low relative to a reference value, can you be 100% sure the last driver didn't just hit the "values are normal" button last time it was driven? (Not that relevant if you're the sole driver)

Secondly, for how many people is a possible/unconfirmed slow puncture an irritation and inconvenience, as opposed to something that needs to be looked at professionally? Hand on heart how long do you give a slow puncture before you take the car in? Most of the time the car will limp along just fine with air being put into the dodgy tyre from time to time. Days? Weeks? Months? I certainly know that I've done it with my own car in the past, and have been in cars multiple times hearing drivers say "I think I've got a slow puncture, I should get that sorted out at some point" In my own car, would I be happy to do the odd 30mph bumble around town with a possible slow? Possibly. Would I ever want to do a motorway run? No, and neither should you. (Maybe a chip in the windscreen would come into the same category...how long did you let yours go before you got it seen to professionally?)

Finally, my "good look" was that and no more. Was it a proper inch-by-inch, wheel-off-the-axle, fingertip search, by a trained eye? Not in the slightest. Perhaps what I'm saying is that if you're thinking "I should get this looked at sooner or later" that doesn't mean at some convenient time, it means now.

Hugo a Gogo

23,378 posts

235 months

Wednesday 10th August 2022
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When you say ' instantly lost all control' what exactly do you mean?

I've had a blowout at 120, it was surprisingly undramatic
Driver's side front tyre

Did it just pull you onto the central barrier

Narcisus

8,125 posts

282 months

Wednesday 10th August 2022
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Hugo a Gogo said:
When you say ' instantly lost all control' what exactly do you mean?

I've had a blowout at 120, it was surprisingly undramatic
Driver's side front tyre

Did it just pull you onto the central barrier
Did he not say that's what happened ?

Hugo a Gogo

23,378 posts

235 months

Wednesday 10th August 2022
quotequote all
Narcisus said:
Hugo a Gogo said:
When you say ' instantly lost all control' what exactly do you mean?

I've had a blowout at 120, it was surprisingly undramatic
Driver's side front tyre

Did it just pull you onto the central barrier
Did he not say that's what happened ?
Well you could scroll up and read it


whimsical ninja

Original Poster:

164 posts

29 months

Wednesday 10th August 2022
quotequote all
Yeah it just took us into the central barrier at a pretty kind angle (so got dragged along it, losing speed relatively slowly before spinning) but that wasn't due to any clever evasive action on my part

Pistonheader101

2,206 posts

109 months

Wednesday 10th August 2022
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hope you are okay

FiF

44,408 posts

253 months

Wednesday 10th August 2022
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Who remembers this, SYP from years back, you're essentially a passenger when a tyre blows at those speeds.

https://youtu.be/Naa3qhFUlUE