Bead left the tire?? The carcass of the tire split between the bead and the sidewall? Got a picture?

(If instead the bead left the rim with recently installed tire, then I'd guess the tube was left between rim and bead during installation. See for example, here and here.)

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It doesn't really matter what Phil is saying, the music of his voice is the appropriate soundtrack for a bicycle race. HTupolev

[URL=http://s214.photobucket.com/...zpsgeurlrt7.jpg.html][/url]

Wow. I'll be interested to hear what the tire experts have to say when they wake up and comment on this.

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It doesn't really matter what Phil is saying, the music of his voice is the appropriate soundtrack for a bicycle race. HTupolev

Holy Shit!

A couple of questions

What pressure did you pump the tyres to?
When did you pump the up ( on the day or the evening before)
How hot was it when you pumped them up
How hot was it when they blew
Was there any existing damage to the rim

BTW this isn't normal and no amount of CO2 would have helped

Either a manufacturing defect or the tire was vastly over inflated or both. As other have asked, what PSI did you initially start with and was the road especially hot? David K.

where are the brake pads wrt the rim when lever depressed. ie were your wearing away sidewall when braking?

I had the same failure earlier this year with a Michelin Pro 4 Endurance tire during a training ride. Ended up having to hitch a ride back home.

I had about 2000 miles on this particular tire (front wheel) and it wasn't an especially hot day. I inflate tires to 110 psi (these are rated to a max of 116 psi). No other problems before or since with the rims, brake pads, or other tires. Since I replaced the tire that failed, I've gone about 1500 miles with a new tire without any problems.

With about 100,000 miles on clinchers, this was the only time I've experienced this sort of tire failure. I chalked it up to bad workmanship on this one tire/bad luck for me. I'm sticking with clinchers.

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"Human existence is based upon two pillars: Compassion and knowledge. Compassion without knowledge is ineffective; Knowledge without compassion is inhuman." Victor Weisskopf.

Hi sra,

Very clear photo.

Looks like a Zipp rim. They can be a tight fit with tires, and the edge of the brake track can be sharp from machining, so it's possible this edge cut your tire casing during installation. The casing "appears" shaved there. It might (or might not) be the area of the tire that was installed last, so moving tightly across the rim's sharp edge. (This isn't an issue with Zipp's carbon clinchers; they're smooth.)

If this seems like the case with your wheel, one solution could be to smoothly bevel the edge of the rim with a flat hand file. The idea is to take off the burr so the tire slips on easier and doesn't get cut in the process. I've successfully done this on several of my Zipp aluminum rims over the years.

Cheers,

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

I had a tire bead come off while it was sitting in my basement. It could easily have blow out the sidewall as it came off, but didn't. I think it was a combination of factors.
1) I inflated them to 115psi to see how much air they'd hold overnight. IN hindsight, being a wide rim...115psi is probably like 120-125 on a narrow rim, and it was pushing the limits there.
2) The newer wide Zipps I think don't have as deep of a bead hook, they are wider, so there's a little less sidewall force holding the bead.
3) They have been mounted and dismounted at least 4 times that I can remember.
4) It's possible that the tube, the last time I pumped them up, managed to slip under the bead. Keep in mind that I had raced on them 3 times since I last remounted them and had even been out in the sun on a fairly hot day.
5) Some sealant had gotten between the tube a tire and worked it's way to the bead.
6) I'ts possible i had a puncture at some point and even more sealant was now between the rim and tube.

I haven't closely inspected the tire and rim. I will when I remount a brand new GP4000S II this weekend.

NOTE: even with a coating of sealant, my front tire still lost about 20psi overnight, so pumping them up is unavoidable. My front wheel is an older Zipp 404 with aluminum rim.

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TrainingBible Coaching
http://www.trainingbible.com

Tyres pumped up in morning at 110psi the rip is at join under sidewall and brakes not close to tyre at all.
The heat was 23 warm for uk :)

It was 94 miles into race !

That looks like a defective tire, or something cut the sidewall.
I've had a similar failure on a 3 weeks old Michelin Pro4, but not during a race.
I race with tubies, they're more reliable [assuming it wasn't a cut sidewall]

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res, non verba

It's a hard call to make absolutely.

Modern clincher tire technology is amazing. They really are a wonder.

With garden variety flats/punctures, where all that is needed is a new tube, if you know what you are doing, a quick tube change can be made in a couple of minutes and you are on your way.

However, there are things that can go wrong with a clincher that are rarely if ever are problem with a tubular - which for some applications, may tip the balance to the tubulars.

Here's an example. My wife raced on clinchers in a road race as part of a stage race earlier this year. She was in a small break-away group battling it out for 2 - 3- 4. She hit a pot-hole really hard with about 800m to go. Front wheel blew out and the force of the tube being blown out, cause the inner tube to become wrapped around one of the forks. Neutral wheel service was right there. Normally this is a really fast change - 5 sec, but it stretched to close to a minute because, they had to wrestle with the tube wrapped around the fork. That cost her 2 spots in the GC slipping from 2nd to 4th! You never know what would have happened, but even if she had flatted with a tubular, she still could have ridden it in over the final 700m with minimal loss of time. Just one bizarre, bad luck story with clinchers.

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Steve Fleck @stevefleck | Blog

My first two thoughts:

1) Brake pad rubbing on the tire sidewall when brakes are applied. Eventually the sidewall gets too weak and splits.

2) Pinched tube pushed the tire bead bead off, and the resulting explosion damaged the tire, or maybe the tire was cut by the rim as you tried to stop.

i'll leave diagnosis of the cause to the experts
on the topic question of "Stick with clinchers or back to tubs" i'd say don't put much weight on this failure in that debate - consider it a one-off freak occurrence (pending determination of the cause and if it might happen again) and weigh up the pros and cons (which does include the reliability issue, though there are arguments either way). from the phrasing of the question i guess you've already had that debate with yourself and decided to switch from tubs to clinchers? i don't see any reason to change you mind based on this.

rolling resistance seems to be pretty equivalent these days so your basic trade-offs are:

tubs:
lighter wheel/tyre combo
generally better control after a puncture
expensive (especially when 1 flat likely means replacing the tyre)
hassle of fitting

clinchers:
cheaper
versatility/ability to swap tyres for conditions
compatibility - can borrow a tube from riding mates

roadside puncture repair is a debated point - some say pitstop works well (my experience says otherwise), some say fitting a pre-glued tub is easier than a tube (others say its fiddly and liable not to stick properly). what your experience here does illustrate is that there are things that can go wrong for which a spare tube is no use, whereas if you're carrying a spare tub then that will fix most tyre related issues (once - while you can carry a couple of tubes no problem and borrow another from others around, carrying multiple tubs gets bulky)

I'll echo what was said upthread and say that it was probably a sidewall cut. What tyres were you using? It may be worth looking at something with a tougher sidewall that's still fast like a Conti 4 seasons, especially if you race on bad roads. Running tubs may not have solved the issue but generally a better tyre all round anyway. Only nancy's ride clinchers :D

Flame away!

To highlight there is no cut tongue sidewall it's the seam that holds the bead in has split! No brake rubbing or cuts. It's the section onto the rim.

Iv went to clinchers as I got a great deal on the zipp 808 powertap wheels :)

I'm gonna have to go home and look at the inside of my gp4000s tires, but I know that the treads look nothing like what is in that photo. Is it possible this tire was put on inside out? Am I somehow looking at this picture in a wrong and twisted way?

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Ed O'Malley
www.VeloVetta.com
Founder of VeloVetta Cycling Shoes
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