Continental GP 4000s sidewall blowout

Discuss light weight issues concerning road bikes & parts.
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by image12

Sad day for a ride. :cry:

Tires: Continental GP 4000s
Tubes: 72g Forte inner lightweight tubes
Wheels: Zipp 404 Firecrests clinchers
Tire Pressure: 110psi

I went out yesterday for a sunday ride with my brother and less than half mile into the ride. Going 25-30mph I hear LOUD pop from my rear wheel, the back starts to fishtail then the rear wheel is locked up and grinding against the road. I manage to stop and in my head I'm thinking it's a tube blowout. I look at the rear wheel and see the whole sidewall of the tire split wide open. The inner tube ejected out of the tire when it burst and wrapped around my hub and brake cause the rear wheel to lockup. Plus the inner tube is still inflated, full of air!
Some more info, I've ridden 380 miles(logged from strava) on this bike/tires, never had a flat on them. Rode a century with no problems. I'm more in shock because I've seen some big gashes and cuts on tires but never seen a tire burst open like this. I just feel like I'm in a crap situation. I'm Bringing the bike into the dealer and hoping for the best. The pictures say much more





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by Kastrup

Looks like a failure due to manufacturing errir.
Sure looks bad...
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by Weenie

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by system787

Wow, talk about bad luck. Glad you're safe. The wear indicators are practically brand new.

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by bm0p700f

I have seen once the bead on these tyre pop out of the carcass causing a similar problem to this. I am running these tyres also at the moment. I hope bad luck is not going around.

I did have one of my supersonic tube go bang on me during a ride. It split at the seam, nothing went through the tyre. Maybe the bad luck is going around.

Glad your safe.

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by stella-azzurra

I have the same exact ones. Looks like a manufacturing failure.
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by prendrefeu

Damn, that sucks.

Glad you're safe. Maybe Continental will send you a new one.
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by tinozee

Similar setup here too - 4000s clinchers with Reynolds 46 rims @ 110psi. No problems yet but your story is scary. I have about 1000 miles on mine and have been surprised to see it hold up with no flats on pretty rough New England roads. Prior to this wheelset I have always used tubulars and tubeless. This makes me want to get back on the tubeless wheels for fall and winter.

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by image12

Yea im glad to not have gone down. I'm really hoping zipp will give me some deal to repair/ replace the rim.

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by thisisatest

"it is probably the crappy zipp hubs."


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by ticou

That's a pretty cheap shot dude. It's the most, or amongst the most, revered tyres out there, I run 'em too, so it's definately a bodge job at the heating press.

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by 11.4

You show photos from both sides of the blowout and, as I would be, seem more focused on the damage done to the wheels. Rightly so.

However, here are my two cents' worth. It looks to me like you had a brake block that slightly chafed one side of that tire right above the braking surface, until it wore through a level or two of cords. At that point it started to separate, the tire emerged, and you had your failure. Different rims need brake block height adjusted slightly, and I think that's what happened here. It's not common for a sidewall to "unzip" like that for a long distance without having another contributor to the problem. That area is where the casing wraps around the bead and back up again, so it's actually pretty damned strong and the casing doesn't show delamination that could have initiated the problem on its own. The casing is still bonded to the bead.

I'm perplexed that you could have had an inner tube at 100+ psi come so far out of the tire, wrap around the frame, etc. and not have blown long before. If you separated the casing at the chafing line, a good size amount of tube could have extruded through the cut and actually reached the brakes/seatstays/chainstays and caused it to jam, though the tube wouldn't have lasted long like that. Note that you have chafe marks all over the side of the tire at the point where you ground your rim. This suggests that the tire had already collapsed at the point when you were grinding the rim -- i.e., a flat or blowout had already occurred.

Tire casing failures due to manufacturing defects are not that common these days. Usually if you look hard you find some other reason, such as an unidentified deflation, a tire cut, a brake block rubbing the tire casing, etc. It seems that you had something like that happen here. I don't think I'd blame Conti based on the photos you show.
Last edited by 11.4 on Mon Sep 10, 2012 8:22 pm, edited 1 time in total.

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by HammerTime2

Very impressed that the 72g <Performance Bike> Forte inner lightweight tube did not "flat" given all the drama it experienced.

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by BigCol

I had similar issue!

Riding down mont ventoux at approx 35-40mph, rear tyre blew out instantly (wasn't braking or cornering), lost control and crashed hard. Didn't break any bones but in a bad way and had to be driven off the mountain :(

As you can see from the pics the tyre and tube were wrecked. Hard to tell how it went due to amount of damage but suspect sidewall blew out. Tyre was approx 150 miles old. HAd done a couple of fast descents on it previously without issue. Used latex tubes for 10 years - always very careful not to pinch and have never had an issue with them.

Video here, sound out of sync though


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by image12

11.4 - brake block as in my pads were on the tires? those would have blown long before from some long descents. I can take more pictures of the brake track, zipps have a pretty large area. The wear on the sidewall is from the tire sliding around the rim.

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by topflightpro

I've seen that same thing happen to a mountain bike before. But the tire was not so new.

by Weenie

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