Author Topic: Bike tire inter tube exploding question  (Read 1790 times)

Loren Ver

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Bike tire inter tube exploding question
« on: May 23, 2021, 11:11:19 AM »
Hello Fellow Bikers,

Question about changing out inner tubes so that they don't explode when you add air :P.  What am I doing wrong?
DH's rides a cheap hobbled together garage sale bike that takes a 26x1.95, Schrader. I'm apparently the bike person in the family so bike work gets delegated to me :).  Over the past two years I've changed out the tire 3 times (always the same tire, rear) and had it explode twice, and it is currently sitting in the garage waiting on a new inner tube since our last one is all exploded.  So my record is currently 33% success, but once we get another tube at best I can get to 50%.  This is ridiculous. I have to be doing something wrong (am I causing pinching by how I am putting in on?) or there needs to be something wrong with the rim or something else?  I went over the entire inside of the tire with gloves to get out any debris that might have caused the original flat.    Help?

About me, I've been successfully changing out my bikes inner tubes for years (700cc, Schrader valve).  Never had an explosion. So I'm not a total newbie at it, or my bike is just a sweet heart and has been treating me well :).  False sense of security maybe?  Jealous junk bike perhaps?

I put new inner tube in as follows for both bikes, works for one and not the other. 
-Check the old tire for debris (we also try to track the puncture etc to get location)
-Add enough air to new tube to give it some shape but keep flexibility
-Put the partially inflated tube in the tire.
-Put the valve through the rim.  DH then hung the tire (valve side up) between two saw horses so I could work around it.
-Slowly work the tire onto the rim.  I use only fingers, no tools.  Mostly a lift the tire and set onto the rim.  This changes more to lift and slide as it gets tighter and harder to work with.
-Once seated, I go hide (sound sensitive) so DH can inflate - tire then explodes around 50 PSI (instructions call for 45-65 PSI)

Advice would be appreciated, the cost of tubes has well out paced the cost of the bike, and we are getting zero use out of them.  So sad. 

Loren


nereo

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Re: Bike tire inter tube exploding question
« Reply #1 on: May 23, 2021, 12:12:58 PM »
It could be a few things

1) a spoke is puncturing your tubes (A: check spokes, replace rim tape)

2) burr on the rim (A: check rim with your finger and notice any sharp metal bits. File down as needed

3) a crack in your tire (A: replace tire)

4) embedded glass in tire - sometimes not noticeable until you bend/flex tire around the puncture sites. (A: replace tire)

Assuming no debris (which you’ve said you checked get previously) these are your most likely culprits, roughly arranged in order of likelihood. If the tubes keep getting flats in the same basic spot it’s an indication that something (spoke, burr, crack or glass) is the problem.

Good luck

PS - you can patch tubes several times with inexpensive tube patch kits. I normally do 3-4 patches before tossing the tub fir a new ~$6 tube.

gooki

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Re: Bike tire inter tube exploding question
« Reply #2 on: May 23, 2021, 12:44:19 PM »
Or you are getting pinch flats (been there, done that). Do not use tyre levers when putting the tyre back on. If they tyres are a tight fit, go on YouTube to see how to do it without levers. It takes a bit of practice but finally solved my problems with flats tyres.

Good quality rim tape is a must.

Loren Ver

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Re: Bike tire inter tube exploding question
« Reply #3 on: May 23, 2021, 07:01:31 PM »
Thank you both for your replies.

The original flats seem to be independent of the exploding.  The exploding only happens when putting on a new tube and immediately.

I've never heard of rim tape and will take a look.  I don't use tyre levers, so I don't think that is my issue, but I'll look around.  I could very well be pinching to cause an issue.

Thank you for the list @nereo I'll go down it and see what I can find once I have day light again. 
We were going to try and patch the previous tube but don't currently have a kit so we thought we'd swap the tube in the mean time, that didn't work so well.  The exploded tube doesn't have a hole but a giant tear of about six inches. 

markbike528CBX

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Re: Bike tire inter tube exploding question
« Reply #4 on: May 23, 2021, 08:57:26 PM »
If the tube has slime and  air source is a compressor, the air might be too hot and starting a reaction.

Loren Ver

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Re: Bike tire inter tube exploding question
« Reply #5 on: May 24, 2021, 03:08:17 PM »
Thank you for the reply @markbike528CBX
No slime, though DH is thinking about going that way for the next tube given our current record.
The compressor is also DH pumping by hand (classic bike pump where feet hold it still and you compress with both hands).  He's pretty hot, but I don't think he causes that kind of reaction.  :)

GuitarStv

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Re: Bike tire inter tube exploding question
« Reply #6 on: May 24, 2021, 03:24:08 PM »
The original flats seem to be independent of the exploding.  The exploding only happens when putting on a new tube and immediately.

Just an idea here:

The tire bead sits on a little lip under the rim of the bike wheel.  With tight tires (and there are some tires made tighter than they have any right to be . . . Continental GP4000s, I'm definitely side-eyeing you here) it's very easy to pinch a little bit of the rubber of the inner tube between the tire and this lip.  Everything will look fine at first glance but when you apply pressure the tube will blow, and depending on how much tube got stuck it can cause a really big hole that is impossible to patch.

I've done this twice.  :P

After you mount the tire, go all the way around the rim squeezing the beads of the tire together and visually checking to make sure that there's no tube stuck in that spot.

Richardp10

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Re: Bike tire inter tube exploding question
« Reply #7 on: May 24, 2021, 04:47:31 PM »
It sounds that potentially the tubes aren’t wide enough to suit the tyres you have. what width of rim, tyre and tube are you using?

Poor Rod

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Re: Bike tire inter tube exploding question
« Reply #8 on: May 24, 2021, 09:15:16 PM »
The original flats seem to be independent of the exploding.  The exploding only happens when putting on a new tube and immediately.



After you mount the tire, go all the way around the rim squeezing the beads of the tire together and visually checking to make sure that there's no tube stuck in that spot.

This. What I do is pump up the tire slightly, maybe 5 to 10 psi, and then deflate it and squeeze the bead on both sides to ensure that the tube isn't caught between the tire bead and the rim. The slight inflation allows the tube to expand to it's shape, but it's not enough to cause the tube to explode. Once you've done this you are good to pump it up to full pressure.

ChpBstrd

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Re: Bike tire inter tube exploding question
« Reply #9 on: May 25, 2021, 02:57:00 PM »
Is it possible your air pressure gauge is bad? For example, if the pressure gauge says 50psi but you've actually pumped it up to 75psi, it will seem like a mystery why the tube keeps popping. It may affect some tires/wheels more than others, but definitely a dangerous situation! Get a 2nd gauge to verify the reading on the first one.

Otherwise, I like the suggestions to make sure your tube is the correct width and to check for bits of tube pinched between the tire and wheel.

Another screw up I've personally done is to accidentally twist a bit of the un-inflated tube while shoving it in. Then you inflate it and it's twisted inside. It sounds like you are not doing this though, because you're putting a little bit of air in it before installation.

Last thought: Try a different brand of tubes. Amazon and eBay have a lot of garbage being sold. You could simply have a bad batch. 

Loren Ver

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Re: Bike tire inter tube exploding question
« Reply #10 on: May 25, 2021, 03:17:27 PM »
Thank you for the replies!  We haven't done any actual work since we are waiting for supplies (the bike store is too expensive if we are going to be troubleshooting this) and we got distracted building a castle in the yard with bunch of pavers a friend gave of for free. The minions needed a castle and we needed to deliver....

Anyway... sizes
bike tire is 26x1.95
rim is 26x1.5/1.75

DH and I have been talking about this as well.  The two tires that exploded were both from the local bike shop (months in between purchases) and where the size 26x1.75-1.95.  My one success (if DH and I recall correctly) was scavenged from a trash bike he found.  It now has a hole (after months of use) and we are waiting on a patch kit. Its size is 26x1.50-2.125 (? the 2.125 is really hard to read, even after chalking over it).  So we are starting to think it is a width issue, which is seems some of you think it could be too.  Maybe the bike store ones just aren't getting fat enough to fill in and get pinched or slide under the tired and then pinch and explode. 

That is what we were thinking last night before placing the replacement tube order, but wanted to brain on it a little more before spending the cash. 

gooki

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Re: Bike tire inter tube exploding question
« Reply #11 on: May 26, 2021, 03:31:23 AM »
Looks like you had the right size tubs so I doubt that's the issue. Feel free to try a different brand and all the advice above - you'll get there.

PS post pics of the castle please.

Loren Ver

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Re: Bike tire inter tube exploding question
« Reply #12 on: May 27, 2021, 10:54:02 AM »
@gooki as requested, here is the castle

Just a little place for the minions (and their cannon) to be.  Yah, it kinda lacks scale...  The tires off to the right (green and brown stack) are car tires that have been painted.  Then to the left, the jack-o-lantern you can see part of is a washer drum. 

We still need to fill in the moat under the drawbridge with some blue rocks or something.   

nereo

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Re: Bike tire inter tube exploding question
« Reply #13 on: May 27, 2021, 10:55:25 AM »
^^ That's awesome.

TrMama

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Re: Bike tire inter tube exploding question
« Reply #14 on: May 27, 2021, 11:33:05 AM »
Your castle is awesome. I assumed when you mentioned the minions before you were talking about your small children. However, I can see I was mistaken and you've upgraded to real minions :-)

As for the tubes, try a better brand. I've never dealt with exploding tubes, but I do notice a difference between discount brand tubes and name brand ones.

Hibernaculum

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Re: Bike tire inter tube exploding question
« Reply #15 on: May 27, 2021, 11:51:20 AM »
Inner tubes blow out like that when the tire is not well seated on the rim. While it is nice to check for debris, and make sure that there aren't any spokes poking out, those things don't cause this problem. Also, using tire tools to install the tube can pinch the tube and cause it to flat upon inflation, but a) you're not doing that, and b) it causes a flat, not a blow-out. The blow-out is caused by a section of the tube getting out from underneath the bead of the tire. The tube, unsupported by the tire, can't hold the proper pressure and will explode like a balloon.

So, as others have mentioned, the procedure is to install the tube as you've already done (since your technique sounds just right there), but upon inflation, only give it a bit of pressure. You want the tube and tire to get to their final orientation, but not without some pressure that the tube blows out. Now, inspect the tire carefully. Spin the wheel in your hand. There should be an equal amount of sidewall visible all around the tire. Some tires have lines on the side. If so, the line should be at the same place all around, rather than dipping high or dipping low. Also, the tire itself when viewed from the side should be the same height all around. No hops. Look at it from the top now, looking down at the tire while it spins. You shouldn't have any side-to-side wobble of the tire. If you have any of these things, first, try to manipulate the tire in your hand. Wrest it from side to side. If that makes no difference, totally deflate the tire, and work the bead around the whole thing, just kind of pulling and tugging on it, to make sure the tire bead is evenly under the part of the rim that is designed to capture the bead. Then, inflate slightly, inspect, repeat if necessary. One more thing that can help is to use something slippery on the tube and tire. For instance, you can use talcum powder on the tube. That keeps it from sticking to the tire if you don't have a flat for a long time, but it also helps the tube to slide against the tire and take the correct orientation when mounting. You can also use soapy water to do somewhat the same thing, for tough cases.

Here's the thing: there's supposed to be a standard bead seat diameter for a given rim and tire. But, due to manufacturing tolerances, some rims can run a little large or small. And some tires can run a little large or small. You can't tell by looking or measuring, just by installing a tire. If you get a small tire and a large rim, then the tire is a bear to install. If you get a large tire and a small rim, then it is more prone to blowing out tubes. Also, some tires are just made somewhat wonky, and you'll never get an even seat for the bead no matter what you do.

So, if you really can't get the bead seated straight all around after you've tried all of the above, replace the tire. And one final thought- you might use a hand pump, if you have one, instead of the compressor. 50 psi is likely more pressure than you need. Generally, what's listed on the sidewall is maximum recommended pressure. For a 2.2" wide tire, you really shouldn't need to go above 35 psi. Higher psi will transmit more road vibration and thus feel faster, but it actually isn't any faster, and if you've got a sketchy tire/rim interface, you're more likely to blow out the tire getting to 50 psi than you would at 35.

gooki

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Re: Bike tire inter tube exploding question
« Reply #16 on: May 28, 2021, 03:29:36 AM »
Sweet castle. The draw bridge is next level.

Loren Ver

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Re: Bike tire inter tube exploding question
« Reply #17 on: May 29, 2021, 06:20:11 AM »
Thank you all for your replies.  We got a new inner tube in the other day. 

I check for spoke, rim, and tire issues before starting and didn't see or feel anything.

Then we took it really slow as suggested.  I think what was happening is the tire was not seating well against the rim and the inner tube was then getting pinched as it was being inflated, causing it to explode as it came up to pressure.  So we just kept reseating it round and round after each little pump of air to make sure seating well and not moving to where it shouldn't be. 

That and we went with a slightly larger size inner tube, maybe a little less movement as it inflates.

Thank you for your patience and expertise!

LV

 

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