Can a blowout knock a wheel out of true?

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Matthew Williams

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Sep 8, 2020, 4:50:15 PM9/8/20
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I was sitting on a log and enjoying the view, when my front tube exploded with the sound of a gunshot! Fortunately, I wasn't riding or sitting on the bike, and it wasn't loaded with gear. The local shop put in a new tube and remounted the tire, but when I reinstalled the wheel, the rim was bent and hit the brake in one spot. 

The rim is an AlexRims--probably stock from Rivendell--with a 700x45C Kenda tire. The blowout was explosive and knocked the bead of the tire out of the rim. I didn't ride the bike until I had the new tire installed, and the wheel was true before the blowout, so I'm wondering if the wheel warpage was caused by the severe blowout or something else. How'd my wheel get out of true in just one spot? Has anyone else experienced this? Do I need a new wheel?

200905_blowout.jpg

200905_view.jpg

Peter White

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Sep 8, 2020, 6:02:35 PM9/8/20
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What pressure before it blew? 

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Ben Mihovk

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Sep 8, 2020, 7:52:10 PM9/8/20
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Hmmm...here's where I'm at on this...

1. I've been told that the ONLY way a tube makes a "BANG" when it pops is when the tube gets outside of the tire (pinch flat)
2. I wonder if you could have hit something on your ride that didn't feel too bad but maybe could have dinged your rim, causing the tube to sneak out?
3. If so, maybe the ding on the rim is why the wheel is out of true?

Again, just guessing. It's weird that you'd get that kind of a flat without something goofy happening...the tire typically wont't get unseated by a flat unless the tube sneaks out. 

It the wheel isn't mangled, I'm sure you could get it trued by your LBS. 

-Ben

Steve Palincsar

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Sep 8, 2020, 10:00:52 PM9/8/20
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On 9/8/20 7:52 PM, Ben Mihovk wrote:
Hmmm...here's where I'm at on this...

1. I've been told that the ONLY way a tube makes a "BANG" when it pops is when the tube gets outside of the tire (pinch flat)


That's not what a pinch flat is, and pinch flats (aka "snakebites") do not make a BANG.  Usually, not even a whimper.    https://www.liveabout.com/what-is-a-pinch-flat-365617


2. I wonder if you could have hit something on your ride that didn't feel too bad but maybe could have dinged your rim, causing the tube to sneak out?
3. If so, maybe the ding on the rim is why the wheel is out of true?


How long between when the tire was mounted and when it went BANG?



Again, just guessing. It's weird that you'd get that kind of a flat without something goofy happening...the tire typically wont't get unseated by a flat unless the tube sneaks out. 

It the wheel isn't mangled, I'm sure you could get it trued by your LBS. 

-Ben

On Tuesday, September 8, 2020 at 3:50:15 PM UTC-5 Matthew Williams wrote:
I was sitting on a log and enjoying the view, when my front tube exploded with the sound of a gunshot! Fortunately, I wasn't riding or sitting on the bike, and it wasn't loaded with gear. The local shop put in a new tube and remounted the tire, but when I reinstalled the wheel, the rim was bent and hit the brake in one spot. 

The rim is an AlexRims--probably stock from Rivendell--with a 700x45C Kenda tire. The blowout was explosive and knocked the bead of the tire out of the rim. I didn't ride the bike until I had the new tire installed, and the wheel was true before the blowout, so I'm wondering if the wheel warpage was caused by the severe blowout or something else. How'd my wheel get out of true in just one spot? Has anyone else experienced this? Do I need a new wheel?

200905_blowout.jpg

200905_view.jpg
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Steve Palincsar
Alexandria, Virginia 
USA

Jim M.

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Sep 8, 2020, 10:17:23 PM9/8/20
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On Tuesday, September 8, 2020 at 7:00:52 PM UTC-7, Steve Palincsar wrote:

That's not what a pinch flat is, and pinch flats (aka "snakebites") do not make a BANG.  Usually, not even a whimper.


Nice T.S. Eliot reference! 

I've seen over inflation do that, but can't think of much else that would.

Matthew Williams

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Sep 8, 2020, 10:18:57 PM9/8/20
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Hi everyone, here are answers to your queries and more information:

1: What was the pressure before it blew? 
Unknown. Probably +70psi. Yes, I now know that was too high!

2: How long between when the tire was mounted and when it went BANG?
4 years. The bike still has the tubes and tires from Rivendell, circa 2016.

3: Did I hit anything to knock the bead out of the rim?
Nope. The majority of my travels are on asphalt and concrete, a few gravel and dirt roads, and I don't jump curbs.

I'm wondering if the too-high tube pressure popped the tire bead out of the rim and then exploded, but I wouldn't think that sequence of failure would knock the wheel out of true.




Ben Mihovk

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Sep 8, 2020, 10:21:53 PM9/8/20
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Yes...wrong terminology (pinch flat). My bad.

Matthew Williams

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Sep 8, 2020, 11:31:47 PM9/8/20
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On Sep 8, 2020, at 8:10 PM, Eric Norris wrote: 

Matthew: 

When you say the “rim was bent,” do you mean that 

1) the wheel is out of true, and the entire rim is moving to one side and hitting the brake pad, or 

2) the rim is straight, but one side is bent out? 

Whoops, poor choice of wording on my part. Yes, the wheel was out of true, meandering in the fork and contacting the brake pad. The rim wasn't "bent" like a paper clip or a bumper; it was mildly warped in one spot--presumably where the tube pushed the tire bead out of the seat and then failed. 

My local shop re-trued the wheel but I'm surprised a blowout could affect a wheel to that degree. I guess I'm just used to my indestructible Sting-Ray! 

spencer robinson

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Sep 9, 2020, 6:04:08 PM9/9/20
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Yes, a tire that blows off a rim can put the rim out of true
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