OldBike876

So...

I built a front wheel for my aluminum commuter that I ride every day. After two weels, I removed the wheel to have a look, tweak the spokes, and so on. On a lark, when I reinstalled the tire, I tried a CO2 filler I have but have never needed.

I over filled the tire, but it didn't blow. I let the air out, refilled slightly and then left it. The next day, I took it downstairs to the bike, installed it, and pumped to the right pressure, and rode around the parkade for a few minutes to see how she worked. All was fine.

Monday morning: flat tire. Completely flat. I had a look just now and found the tube with a gash in it and the tire installed with the bead exposed. Maybe I damaged the bead installing the tire, but I think I'd notice that. Also, the bead was off the rim right next to this damage.

I have removed, patched, replaced tubes and tires many times, I've never seen something like this. Do you think I cocked it up? If so how?

Thanks in advance.

FBinNY 

OK, thanks for the photos because they told the story better than you could have in words.

It's a clear case of tire body failure. The proximate cause was probably the prior over inflation which tore some fabric. Initially it wasn't enough for immediate failure, but once there was partial failure, more threads broke progerssively,like a fraying rope, until it let go.

There's also the possibility that a brsle shoe was overhanging the rim, and scored the tire, which is fairly common, so double check for evidence of that.

OldBike876

Hmmm, user error, as i expected. I am glad I wasn't riding it when this happened.

dsbrantjr

Interesting that there is damage to both tire beads. I wonder if the beads were damaged during installation.

OldBike876

That's a good point. These tires go on and off quite easily, so i have never really reefed on them.

Andrew R Stewart 

I suspect some form of abrasion on the tire's bead. You can see the worn/roughened bead just below the actual wire blowout. This can happen if the tire was not fully seated and than ridden. the edges of the bead sits on the rim's top edge and that rubs enough to slowly cut through the casing fibers that wrap around the wire. This type of failure is not generally a fast happening one, unless the device that caused this was particularly sharp (like a screwdriver or knife) and much of the cutting happened when the "lever" was slid along the rim, between the rim and tire bead. That the bead's rubber coating shows no abrasion above the wire blow out location makes me think it was a tool and not a brake pad that did this. Andy

OldBike876

Interesting. I often use a plastic lever if need one. Serves me right for hamfisted installation, I guess.

79pmooney

Oldbike876 - three points. 1) watch the tiny line on the sidewall just above the rim while spinning the wheel in your hand after mounting and inflating the tires. It should stay rock steady above the rim, telling you the bead is properly and evenly seated. And 2) with the rim properly seated you should never see the blowout, tire coming completely off the rim and jamming in the stays or fork that I had the chance to witness from the driver's seat. (It was not fun. A top five crash. Collarbone, ribs and a hard helmet hit. Acre of abrasion.

3) Rims vary in diameter. Yes not much. Tires do too. Tires age and stretch. We all know of rim-tire combos that are a bear or worse to mount. Well there are tire-rim combos that simply aren't safe. If mounting seems just too easy, maybe consider whether you actually want to chance riding that wheel. My tire in my example above was one of those too easy fits. I just threw it on because I had it and wanted to ride in town and back.

All advice to keep you off the pavement. And about your bike - it's a good one. Quietly arranged to have my incident happen when you weren't present. This wasn't the bike's fault. But maybe it had a hand in your fate. Keep it. (The bike in my photo pulled a minor mechanical 20 miles and 2000' from home. Took all the fun out of the ride. I had to baby it down the great descents. 5 miles from home the front end started bucking every time I touched brake. Both fork blades were about to snap. Cracks totaling a full "lap". The cause - a combination of decisions between myself, the frame builder and the plater. We pulled a metallurgical no-no. Bike bailed me out big time. Keeper.)

Edit: Front wheel. Mine was a rear. Front ratchets up the damage to you. Again, good bike!

FBinNY 

Yes, I only mentioned the brake shoe possibility because I always double check for alternate possibilities to avoid repeat failures. Murphy's Law dictates that what I miss will bite me later on.

As for the damage to the opposite bead, abrasion is a possibility, as is water damage --- note the rust. However the over inflation remains the most likely proximate cause.

Just as a chain will fail at its weakest link, the stressed body failed where it was weakest.

OldBike876

All good points.

Also, iI like to imagine the bike down in the parkade letting out it's BANG while a neighbour walks by. That'd make for a memorable night, I'm sure.

zandoval 

There is also the possibility of getting a defective tire. Twice I have received new tires with defective beads...

https://www.bikeforums.net/22308392-post2.html

Sy Reene

I'm curious though, what size tire was this, and what CO2 cartridge size? A 16gm CO2 should fill a 700c tire to a non-extreme pressure, no matter the width.

OldBike876

It's a 700c Schwalbe... 45mm wide, I think. I used a 16g CO cartridge to fill it. I had pumped a small amount into the tube beforehand to mount everything, but that was just enough to keep the tube round. I admit that I was surprised at how quickly it filled, hence the overinflation.

cyccommute 

Tire levers can be hard on the fabric at the wire bead during removal. Sometimes when you push the second lever to remove the bead, you tear the fabric over the bead. If the quality control of the tire isn’t the best, you may have too little rubber covering the bead and it tears off. It happens and not much you can do about it once the damage is done.

See the rubber on the bead that the red arrow is pointing to? If you look at the part of the tire that the green arrow is pointing to, there isn’t any rubber covering the fabric of the tire casing. This is typical of the kind of damage levers can do to the bead…even on tires that are easy to remove.


It had nothing to do with inflation nor over-inflation.

maddog34

there are three brands of tires that i rarely reuse on a used bike rebuild... Innova, schwalbe, and continental. All three brands have a high problem rate, but different reasons for failing.
note the rusted beads,,, that tire was about to fail,and then you helped it fail by flexing that bead.

be happy it failed while you weren't riding the bike... and go buy a lotto ticket before your luck changes! :-D

Sy Reene

So a 16g cartridge would approximately fill a 700x45 tire to about 30psi. At least from guestimate using this random chart

OldBike876

Huh, I thought Schwalbe were ok. What brands do you choose instead?

OldBike876

Weird. I didn't put a guage on it, but it was WAY over that. I must have had more air in there than l thought.

FBinNY 

We'll never know the actual pressure, nor does it matter.

First, we don't know how much was pumped before the cartridge was used, so the final pressure could have been significantly greater than the chart indicates.

More to the point, the fail pressure might have been much lower because the body plies at the bead were compromised by age, water, and/or abrasion.

What we do know from the photo is that it was caused by over-inflation ----- not necessarily according to rated load, but certainly to the tire's actual condition.

maddog34

they show up here... i don't go after tires.

i've seen several beads like the thread is about... i also see schwalbes with out-of -round and too tight issues... the contis are almost always tough to seat, or even just Get On some rims.... the Innovas can show seam cracks in a matter of weeks, can slip OFF the rims too easily if not well centered, and some cause customers to think the rims are bent due to SERIOUS side-to side wobblies, bead-seated or not.
*batch variations may deliver different results*.. which may also answer WHY the companies are having quality issues, eh?

Remember those Firestone tires that flew apart on several hundred Ford Explorers an couple decades ago? it wasn't JUST that size/style that had that problem... i had a set of Passenger all season Firestones on my Nissan truck... they Delaminated too... 4 out of 5 of that set...a nd THEN, a borrowed Subaru at a rally with Firestones had THE SAME PROBLEM, leaving us stranded for two hours in a snowstorm, During a rally... i was driving advance car that day... ProCar loaned me a road slick to get us out of the woods... in the snow... with the car's doughnut on too... in the snow. A set of Coopers the next day had zero problems, even after diving into the ditch to avoid a drunk spectator in a jacked up blazer....Trask River area, Oregon Coast Range, Oregon Trail Pro Rally, just south of the Fish Hatchery. The wet snow was 6" deep up on top of Hembre Ridge that Sunday... the problem with the Firestones was traced back to an Over-Zealous Floor Manager wanting to get a bonus and insisting Inferior Materials be used... he was warned by the workers.