Tyre blowout, ripping along bead?

alaimacerc

Had a rather energetic blowout the other day: seems to have worn, ripped or split right above the line of the wire, a couple of inches. Went pretty energetically -- huge bang, and the tube seems to have actually lost a piece of rubber from the middle of the hole. I assume that's now sitting somewhere in the middle of Model Farm Road.

Any particular cause for this sort of failure? Don't think it's a brake issue: too close to the bead, and the blocks seemed to be well-adjusted. Looked too even to be damage from debris. Just something that randomly happens after a certain amount of wear, cross fingers one's not doing 55kph downhill when it happens?

Cee-Jay-Cee

If there was no mechanical interference then it was most likely a defect in the tyre itself. How old was the tyre and how many miles on it? Older tyres start to perish and the rubber hardens and therefore weakens. A bump on the road may have put just enough pressure on that point for it to explode. These things happen.

07Lapierre

Cee-Jay-Cee wrote: »

If there was no mechanical interference then it was most likely a defect in the tyre itself. How old was the tyre and how many miles on it? Older tyres start to perish and the rubber hardens and therefore weakens. A bump on the road may have put just enough pressure on that point for it to explode. These things happen.

It could also be a damaged tyre if it was fitted using tyre levers.

(Tyre levers! my pet hate...never use them if at all possible)

JBokeh

Had the same happen to me on thursday, only I didn't really pay much attention to it because it didn't go flat. I had the tyre casing rip just above where it meets the bead, what happened then is the threads in the carcass tore and the tube started poking through, and due to the carcass tearing the tyre developed a buckle and rubbed my chain stay on one side, and the tube was rubbing the seat and chain stays on the other side. I tried get a pic of how close the tube was to the chain stay but the picture isn't from a great perspective, it was poking well proud of the edge of the tyre

My diagnosis is that it failed because I'd tend to run 22psi for mountain biking, and around 55 - 60 if i've to do some road miles, and the tyre flexes more at low psi and rubs the rim when mountain biking, and then inflating it puts more stress on the damaged bit, this cycle getting repeated will probably wear the tyre where the bead is. I think what i'll be doing is putting the bike in a stand with the rear tyre off, and putting it in a high gear, getting someone to turn the pedals and rounding off the edges of the rim with a file

aFlabbyPanda

I had this happen before with a tyre that was only a few months old. I contacted the company I bought it from and sent it back. They replaced it since there was no sign of wear/rubbing on the tyre itself.

alaimacerc

Cee-Jay-Cee wrote: »

If there was no mechanical interference then it was most likely a defect in the tyre itself. How old was the tyre and how many miles on it? Older tyres start to perish and the rubber hardens and therefore weakens. A bump on the road may have put just enough pressure on that point for it to explode. These things happen.

Not at all sure how many miles, due to serially dodgy bikeputer and taking note of such things... low thousands, I suppose. About a year old I think. Normally I just run 'em into the ground, and have only previously had a blowout when there was obvious physical damage to the wall.

07Lapierre wrote: »

It could also be a damaged tyre if it was fitted using tyre levers.

(Tyre levers! my pet hate...never use them if at all possible)

Hrm, guilty on that score, have been known to resort to those.

I'm wondering if this was a somewhat more "delicate" tyre than I'm used to... was one of the Contis from the road tyre "amnesty" a while back. Actually now that I think about it, first folding tyre I've ridden on, though I've been carrying around one as a spare... for just such contingencies! (Though this time I just trudged sadly home the last 3-4k.)

07Lapierre

alaimacerc wrote: »

Not at all sure how many miles, due to serially dodgy bikeputer and taking note of such things... low thousands, I suppose. About a year old I think. Normally I just run 'em into the ground, and have only previously had a blowout when there was obvious physical damage to the wall.


Hrm, guilty on that score, have been known to resort to those.

I'm wondering if this was a somewhat more "delicate" tyre than I'm used to... was one of the Contis from the road tyre "amnesty" a while back. Actually now that I think about it, first folding tyre I've ridden on, though I've been carrying around one as a spare... for just such contingencies! (Though this time I just trudged sadly home the last 3-4k.)

NEVER use levers to put a tyre on. Easier said then done I know, but really can't emphasis it enought. I'm talking road tyres...

manwithaplan

I've had a couple of conti GP4000S fail along the sidewall. Lately I've been thinking that I should pay more attention to when they were made - I usually buy them cheap and 4 at a time off one of the German sites. I wonder if they get them cheap off the distributors/manufacturers when they are nearing their sell-by date (do tyres have a sell-by date?).