Very disturbing, looking at how much tread you have, seems like a pretty darn new tire. This is one reason why I'm a bit wary of the GP4000

My tires were less than a year old. It was a front tire too, so not much wear at all.

A Google search of these tires shows numerous reports of Continental Grand Prix sidewall failures. Saw a video were the sidewall blew on a rider who was on a flat road, no braking.

Here in Switzerland we have Suva. This is an accident insurance which is mandatory and they investigate things like this very seriously. Continental has to be held accountable for these catastrophic failures.

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"Your Attitude Determines Your Altitude."

Wow. You are right. Lots and lots and lots of talk and pictures of sidewall failures. I didn't know. Mine had a sidewall failure descending down a 4 mile hill. LUCKY it was at a particular nasty curve just before the only traffic light on that hill so I slowed down expecting a red light. Managed to come to a stop without crashing.

For those looking for a similar tyre, you might consider the Michelin Pro4 endurance; the rolling resistance is a bit better than than 4 Season, and it's pretty close in puncture protection. Tis what I got after a 4 Season I was using received a huge gash (so much so that the inner-tube was sticking out of the hole) after several months of sporadic use.

Looks like brake pad rub to me.
Post up a pick of your front brake showing the pads position and shape.

Also a pics of the entire sidewall of the tire, not just the failed section.

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"Your Attitude Determines Your Altitude."

Sidewall away from the failure.

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"Your Attitude Determines Your Altitude."

Another point: 303's have a toroidal shape which effectively moves the brake pad away from the tire sidewall.

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"Your Attitude Determines Your Altitude."

Looking at the pad you can see the curve worn where the pad has been going off the top of the rim.
User error.
Put your wheel back on and squeeze the brake hard and see where it is resting.

And whats the go with the rim edge in the top of your last picture?
Looks like it has been ground away.

The pads were absolutely within the brake, not even close to going over the edge.

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"Your Attitude Determines Your Altitude."

The ground down part is where the rim hit the pavement. I think you should install these tires and go down an 11% grade in the Alps and give us all a report how your expert experience prevented sidewall failure. BTW why don't you tell that to the other folks that have reported Continental sidewall ruptures genius. I hope you never have to take an ambulance ride to the emergency room and have nurses check your pupils every 30 mins throughout the night with a penlight for response.

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"Your Attitude Determines Your Altitude."

Yeah, it's tough to prove user error given the evidence you've provided. In any case, sorry for your accident, and good luck resolving it one way or another.

Look, I and everybody here is sorry for your accident.
We all hope you recover well with no lasting complications.

You mention other instances, but the only ones I have seen have not been atyre falling apart.
I f you understand how these tyres are constructed, you will realise that there is no joining happening there.
There is also no threads hanging out indicating carcass failure.

By all indications, the tyre was burnt/ cut by the brake pad.
The pad is obviously curved where it overhung the wheel.

I myself run zipps with those pads and they wear quite fast and require regular adjustment to keep them on the brake track.
Especially so on the side you have the failure as the brake arm is very short on that side and swings up in an ark quite dramatically.
Yes I do understand riding in the hills, I live at the top of a 24% grade.
All of my riding includes long decents, very often in the late teens or low twenties type pecentages.
I have caught my own pads nearly off the brake tracks on that side after particularly long rides with big decents.

I check my pads after avery ride now.

@ rob2681
I hope you are okay now. New to this forum, I can' see if this is a 2018 issue - or earlier.
For your information.
I ride a disc brake road bike and had a side wall failure in the form of a blister - perpendicular to the side wall.
This occurred whilst I had only done less than 200km with my new set and already suffered a couple of punctures (one at the rear, one at the front).
So to start with, I was not impressed by this supposedly rock solid tyre.

The side wall blister did let the tube out. I was lucky I noticed this whilst still climbing up a hill. I was even more lucky to have a MAVIC assistance van - from whom I bought a Mavic tyre. I eventually finished the Sportive (The 2018 Ardechoise - a 170km gran rondo, with 3500m of hill climb ... and some deep descents too). It happened with â…” of the race still to go. I can tell you I was in a state of shock - as I could have found myself in the same terrible situation you are in : fall in a fast descent. I am not sure I would still be here to talk if that happened.

I did not hit any pothole on the road, not hit any kerb. For me, the issue on the side wall is likely to be a design fault - which Continental will of course never admit. If it is not a design fault, then the likely causes are either : bad batch of material (compound, threads, ...). it could also be a bad lay-up during the manual manufacturing process and finally perhaps not picked-up by quality controls.
I come from a professional world where safety of the product in use is the single most important matter.
It does not matter to have the "best" product on paper if, when installed, the surrounding environment makes it weak.
I sort of understand that a badly installed brake pad will damage the tyre. I also get that a low inflated tyre will cause issues on the side wall (let alone cause pinch flats).
However, I cannot understand how and why Continental were so bluntly dismissive when I contacted them to relate my issue.
This was not a case of getting a free tyre from them, as my on-line merchant reimbursed me for 2 tyres immediately).
No, I only mentioned this so that the manufacturer would know about this and would perhaps investigate internally of possible causes (I did not send them my tyre - as I left my worn out tyre to the Mavic assistance guys, as I was not in a position to cycle the remaining 100km with a tyre around my waist ;-)

At that time, I was not aware of any other issues - like yours.
Continental's responses were shocking : they claimed they have no problem with the product, nor with the process, nor with anything.
I then found similar issues and pointed them the web links I had found - and relating similar problems.
I also said that many happy thousands of customers cannot hide a recurring issue, with publicly available testimonies.
Still, they said they could do nothing if they didn't have my tyre in their hands and could not investigate. they re-iterated the facts that their product was well made, with no manufacturing default and made strong suggestions that I probably hit a pothole, or stone or badly installed my tyre.

Before I used those tyres, I rode with Micheli Pro 4 Race tyres. I used them for nearly 5000km. I only had a couple of punctures at the end (the tyres were quite worn out). I must also mention that I inflicted my Michelin tyres some very harsh training conditions, as I rode many, many kilometres on gravel roads, full of potholes. I did this intentionally on y standard Michelin, as part of a training for a race which did have a gravel section. Those behaved so well (not even one puncture !), were reasonably cheap : I am now wondering why I did choose those stupid Grand Prix 4 seasons.

I read of course the online comments and asked other riders theirs thoughts before buying.
Of course, there are many many happy cyclists with those tyres - which certainly proves a point - that when it works, it works well.
This experience has showed me though that this product is either strongly subjected to a meticulous installation (not practical in real life - particularly when riding). Or worst, the product suffers from a design fault or some issues in the manufacturing process. All of this is of course denied strongly by the manufacturer.

So be it. I am very disappointed and angry by the manufacturer's answer and stance. Very arrogant.
I will not risk my life - knowingly - on Continental tyres anymore.

all the best to you.
Lionel

By the way, being literally disgusted by Continental's attitude, I had to change my two tyres - with only 2 weeks to go before my major cycling sportive (The Etape 2018). I have not been in position to really trial my new set-up before the big day. I felt really awkward until I eventually passed successfully the Glières gravel path - without a hitch.

This is my current set-up.
- Michelin Lithion 2 Reinforced tyres
- Slime inner Tubes inside.

on my standard Shimano SHIMANO WHRXr31 disc wheel set.
My rotating mass is awful - so be it.
I am safe.

I went away from Michelin (Pro Race)a few years ago, because of a sidewall failure in a training race while doing 35mph. I stayed up thankfully. Also, they were fragile and didn't last long.
Been on GP4000 and Supersonics for TTs and have had no sidewall blow outs, they are durable and roll fast.

Interesting to see you went the other way round (on GP 4000 though - not 4 season).
More importantly, good to hear you stayed up.

Sure, there are external factors and conditions that will affect a product's performance.
I might have been particularly unlucky for 2 punctures in less than 200km. But I don't believe in bad luck when issues are arising successively in such a short period of time for me.
I also take on board that I might have been the root cause during installation ... but I also fitted quite a few other tyres in my life!

No, in the end, whilst there is no perfect product (not even my current super heavy Michelin Lithion 2 Reinfoced at 300gr. a piece).
I really struggle to understand the head in the sand attitude and arrogant response from Continental.

So, just to be clear, are you saying you never hit a pot hole in 200k of riding? In my experience (which is with GP4000), the "blister" can occur a considerable time after the sidewall is damaged by hitting a pot hole. It can take some time before the inner tube can squeeze itself through the weak spot (I am guessing that is what you are referring to as a blister). Not to say that Continental should get all the way off the hook -- I do think that hitting pot hole which immediately or eventually results in a sidewall blow out should be a normal failure mode.

Absolutely : smooth road, no kerbs hitting, no pothole either and correct tyre pressure.
To clarify : 200 kilometres. Not 200k ;-)
I fitted those GP 4 Seasons and did less then 200km in total (actually it was less on the front tyre) and about 200km on the rear one.
I totally agree with you : hitting a pothole or a kerb will damage the tyre. I know it too well, as it happened to me on my car - as I was avoiding a motorcycle coming too close to me. I hit the kerb with my rear right tyre which was then irreversably damaged on the side wall. I had to change my two rear tyres (for good tyre wear balance) as a consequence. Funny or not, it was also a Continental tyre. But this is no fault of the tyre.

On my initial Michelin Pro 4 on the contrary, I hammered them and was not particularly gentle with those (gravel roads, kerbs at low peed, low pressure, pot holes. The whole lot).
Only 2 punctures, which were self induced - as I was stopping along the pavement to rest a bit, I rode on sharp stones and glass debris I didn't see.
They lasted nearly 5000km and they are not well known for their puncture resistance - nor their overall resistance.
They did prove however to be more than worthy.

Again, the chords are at an angle to the damage you describe.
Bicycle tyres are not radial construction.
There is no manufacture failure mode that will produce what you describe.
The wall was cut by one of the billions of stray little rocks/debris/glass/bits of metal on the road.
A tar sticky rock can also jam between the fork and the tyre and cut the sidewall.
This may well be the damage mode of the original poster.

Don't ride in the gutter where this stuff resides.
Experienced riders know how to constantly scan the road and miss most of this stuff, some people just keep riding straight over anything in their path and blame the world for their inattentiveness.

For the folks with sidewall blow outs, do you use tire irons to install the tire? This can cause unseen sidewall damage, that does't reveal itself until it blows out.

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Athlinks / Strava

Just in case everyone missed it, this thread is two and a half years old now.