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Coming home tonight - A12 - not a lot of traffic.. got a slight vibration - pretty sure either a tyre or a wheel bearing was rapidly on the way out. Instinctively eased off (but in retrospect should have braked hard and then let the pedal go).. BANG. Rear offside made a noise similar to someone bursting a crisp packet an inch from my ear. I was on a gentle lefthander and anticipated losing an oversteer, but thankfully it was slight and I caught it. A minute later I was in the layby. Tyre was smoking - I waited a good 10 minutes before changing the wheel - even then it was sticky andf hot still.

Inside sidewall ripped in two places, but I think that was a consequence rather than a primary failure (but can't be sure of course).

Spacesaver fitted - was brand new 12 miles ago, now it's about 30% gone. By the time I get to work in the morning it'll be on the canvas. Silly bloody things. I feel sure they must be on dodgy grounds legally.

That's the second time I've had a catastrophic tyre failure. The previous one - 20+ years ago and at about the same speed was a front - and much easier/safer to control.

WoW!

Never had a "Proper" blowout!

AIUI There is almost always a "Reason" for this sort of thing! I wonder if you will be able to find out what the "Reason" actually is?

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"The road to a police state is paved with public safety legislation"

Sounds like a typical 'underinflation> overheating > failure' sequence.

Now if we had a good way to pick up either of the first two stages we could avoid the third.

I know I've mentioned it before but I check tyre temperatures with my hand every time I stop on a fast run. It only takes a few seconds. Any extra heat in a tyre is an excellent early warning sign.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Brainstorming style thought: Infra-red thermometer? Or would that require the wheel to be stationary?

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Andrew.

There was such a system around in the 80s with heat sensors in each wheel arch. I don't know what happened to it. Maybe it's still available?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

I know I've suffered an offside blowout on the M40 in the past and changed the wheel myself but, given the potential risk, ideally shouldn't you call out the AA?

Is it a good idea to change an offside wheel on the hard shoulder of a motorway, or alongside a high-speed dual carriageway such as the A12?

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"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

Pressure sensors in each wheel, linked by some wireless magictrickery to an onboard computer?

Oh, we have those already. Well I do and they are pretty picky about pressures. Although if you picked up a slow puncture in a warm tyre the extra pressure created by the air warming could cancel out the loss of pressure due to the puncture until it was too late.

I did call the AA. ETA was 1 hr 20 mins. I had animals to feed and knew I coud do the wheel change within 5 minutes (once it was cool). I played the percentages and did it myself. I had already decided the tyre (and probably wheel) was a write-off so rode it flat to the lay-by before even stopping, let alone changing the wheel. I was reasonably happy with this given the light traffic.

soon to be standard fit in the US.

What a great tip and one I'll pass on. Thanks Paul.

My driving school car should have a spacesaver in it as standard, but it's an ex AA Driving School vehicle and it came to me with a 'proper' spare wheel!!

I don't think so. If the rise in temperature brought the pressure back up the temperature would stop rising and the high speed failure would be averted.

We need a 'runaway' condition to precipitate the failure, and that means low pressure throughout.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Do you happen to know how they are powering the sensors / transmitters? I always thought that part of such systems was horrible. Sooner or later there's going to be a flat battery in a wheel and a right pain to replace it.

Or will they change the batteries every time a tyre is changed? Or is there some sort of 'generator gizmo'? I once thought you might be able to power such sensors with piezo-electric effect.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

i beleive most systems are self-powering.
the tricky bit is working out (cheaply) which wheel is which
which the US legislation requires you to do at the start of every journey within X minutes (can't recall the numbers).

I was at a seminar about six months ago. One of the talks was on this very subject - harnessing vibration to power small thingies. I'll see if I can dig the paper up some time. This is obviously a prime application (although the applications that were being discussed were far more, er, macabre.

Interesting. I've been picturing a 'crystal' microphone. Do you remember the flat thing with a gold grill that was ubiquitous 30 years ago?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

What I know about mine.

If one is missing or faulty the computer reports it.

I'll have to dig out the manual, can't remember if a flat carried onboard is reported as low pressure or missing. IIRc it's low pressure.

The pressure sensor is part of the valve assembly so fairly easy to replace but is not replaced as a matter of course at a tyre change.

go crazy...
smartire

BLOWOUT - many years in AFRICA , got one at 70 mph- high sided 4x4 --no sensors just a standard road - controlled with brakes /standard anti kid driving. Blowout due to poor quality tyres on vehicle.

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lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

Roger, good to hear you are ok !!



Just a question why brake hard? I was taught to ease of the gas and keep braking to a minimum as it is the course of action least likely to contribute to unbalancing the vehicle further.


Space saver spare tyres, a pet hate of mine, have a sort of one on the C4 but is not, I know, sounds odd, but my car has 17" wheels on it so they have put the standard 15" wheel from the base model in as a spare, it is slightly slimmer than the 17" so does affect the abs and traction control slightly so they have designated it a 'space saver tyre'.

I did get in touch with Fifth Gear when they were doing lots of crash test articles on the programme about testing SSSW's, the response was that they didn't think it would be of interest and wouldn't get a favourable response.

I took that to mean they would embarress to many car manufacturers !!

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I am referring to the short but very definite period when the wall had ballooned (vibration/warning), the tyre was about to go, but was still capable, for that limited period, of doing its job. In that window of opportunity, perhaps a second, I should have eliminated a lot of speed, being ready to lift off the pedal immediately if it went.

I did not - and would not - brake once it had gone (except where loss of control was potentially less bad than ploughing straight into something).