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Been running a set of quite nice slicks at 120-140 PSI for a couple of months. Might have done 400-600 km on the bike in that time. Tonight the rear tire exploded while the bike was sitting in my entryway. It's split right along the seam, with a roughly 2 inch long gap. Very loud bang etc.

Before I go out and buy another $70 tire, I want to get an idea of what caused this. Some possibilities that I've thought of include:

  • Running the tire at 140 PSI. The tire is rated to that pressure, but maybe this is still too much?
  • Some brief stretches of gravel road (1-2km) I did on it last weekend. The bike seemed fine then however.
  • There is a central heating/cooling vent directly adjacent to where the bike is stored. Perhaps the changes in temperature were enough to damage the tire?
  • The roads in this area are not always very good. Maybe this is just the result of accumulated damage from dozens of minor nicks and bumps?
  • The tire could be defective.

Edit: added a picture. Looks like the tube has a ~1cm hole in it.

enter image description here

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Please post a picture. –  cherouvim Sep 7 '13 at 2:31
    
Defective rims are another cause of tire blow out.... –  mattnz Sep 7 '13 at 2:47
    
What size tire? And how old is it? –  Daniel R Hicks Sep 7 '13 at 11:07
    
@DanielRHicks It's 700x23, and about 2 months old, maybe a little less even. –  John Doucette Sep 7 '13 at 15:04
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3 Answers

up vote 2 down vote accepted

From the picture it appears that the tire simply failed. It may have gotten "bruised" at some point, or the cord may have simply fatigued to the point of failure.

Without examining it in person it's hard to tell where the split started, but it appears to have split mostly along the joint between tread and the white sidewall. In general, white sidewalls make the tire weaker, both because the white material is not as durable and because there's a necessary seam between sidewall and tread.

Also, the tire likely has some sort of belt under the tread area, and, in such a narrow tire, that can result in fatigue along the edge of the belt.

The heating/cooling vent could have been a factor if hot air were blowing directly on one spot on the tire, but seems unlikely if it was cooling air.

And, of course, it's always possible that you had cut/bruised the tire at some point and it finally let go.

Age would be another suspect, but you indicate you've only had the tires a few months, and it would take several years for that to be a factor.

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Thanks for the answer! To be clear though, the sidewalls are black - the white bit to the right of the tire in the picture is a deep rim. Do you think the colorized white stripes on the tire could be a similar point of failure? –  John Doucette Sep 7 '13 at 16:05
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@JohnDoucette - I meant the white stripes. They create a discontinuity in the rubber that can contribute to failure. –  Daniel R Hicks Sep 7 '13 at 18:05
    
Very interesting. Indeed, on closer examination, it's split right along the discontinuity. Reviews of other similar tires on Amazon point to the same issue - blowouts along the seam at high pressures. Will switch to a solid tire I guess. –  John Doucette Sep 7 '13 at 20:06
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@JohnDoucette - Of course, one would have to examine the tire closely to determine (if even possible) where the failure originated. It could have started mid-tread but then the "zipper" effect would still have found the "path of least resistance", which is along the stripe. –  Daniel R Hicks Sep 7 '13 at 21:24
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My guess is cords were damaged on the ride creating a weak spot. Threads held together long enough to get you home and a bit longer, then ripped apart. This kind of delayed and catastrophic failure is not uncommon. Heating vent might have softened them enough to make a difference, but the tire was damaged anyway (assuming warm, not very hot air).

More puncture resistant tires may help prevent it in the future, but you cannot prevent it completely.

The size of the hole in the tire, and the hole in the tube are irrelevant, its a symptom of the tire failure, not the cause. Once the tire fails, there is nothing stopping the air pressure inside the tube expanding - the tube cannot stop it, it gets pushed though the tire, making that hole bigger and blows up and pops just like a balloon, hence the bang. If you were listening closely, the bang was preceded by a short ripping sound.

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Either you damaged the casing or it was defective to begin with. Once it starts to go it basically zippers open in an instant. The white tread and the vent had nothing to do with the failure, but the 140PSI certainly could have encouraged it. That's not to say it wouldn't have happened eventually at a lower pressure anyway, but to digress slightly, just because your tire says you can run 140PSI in it doesn't mean you should. At some point you are actually slowing yourself down by running higher pressure (unless you're rolling on a glass flat surface, which you're not), and you are most certainly making your ride less comfortable. This gives me the opportunity to post one of my favorite graphs:

enter image description here

No reason to be dogmatic about the pressures listed here, but they do give you a good starting point. Don't always pump your tires up to their max pressure. Even if they say they can handle 140psi it doesn't mean you should pump them up that tight. It makes the ride more uncomfortable and it does put more stress on the casing and bead of the tire. If something is going to go wrong with the tire, it's more likely to happen the more air you put in it.

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Thanks, but w.r.t. your chart, I am a bit over 180lb, and inflated to the maximum pressure indicated on the sidewall. In fact, part of the reason I got a tire rated to a higher pressure was that I very often get pinch flats on a lower tire pressure! –  John Doucette Sep 7 '13 at 20:04
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You may want to consider moving from a 23 to a 25 if your roads are that bad. Might reduce your pinch flats and make your ride a little more enjoyable. The Specialized Roubaix is a good one and a bit of an oddball. It's a 25 tread on a 23 casing. Most people who run them like them. –  joelmdev Sep 7 '13 at 21:15
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