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  1. #1
    Senior Member franswa's Avatar
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    Spontaneously exploding tubes

    Not sure what's going on but three tubes burst on me today - the bike was stationary. Two tubes in the rear and one tube up front. Last week I swapped the wheels from my Batavus to my Fuji to compare the weight difference. The tubes and tires that were on the Fuji were transferred to the borrowed wheelset. I swapped the wheels back to the Batavus today, reinstalling the tubes and tires that were on them before. While I was installing the rear wheel back on the Batavus, the tube/tire started to expand and bulge at one spot on the rim until it explodes. The carnage that was left on the tube was a long slice approximately 6 inches long. I install a second tube and the same exact thing happens, leaving a similar slice on replacement tube. Fast forward three hours later...I'm in my home office and a third explosion. This time the front tube! Odd that it was delayed. I've checked both tires and rims and everything seems fine to my eyes. Any idea what may be causing this?? Sun M13II rims and Panaracer Pasela PT tires. Kenda tubes.

  2. #2
    bro
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    check the rim tape or rims for burs? i seriously though have no idea what could be causing this. check the tire for something embedded in it too

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    The way you get the explosive sound and long gash in the tube is that part of the tube first escapes from the tire, then that part rapidly blows up like a balloon and pops. If the tire is undamaged then the tube must have escaped from under the bead of the tire. Either because it was trapped between the bead and rim on installation or because the tire bead wasn't properly seated in the little lip on the outer edge of the rim. (Other possibilities are a tire that's made a bit oversize vs. a rim that's a bit undersize, or a defective bead - but those seem unlikely when you have multiple failures.) When you install the tire and tube on the rim go all the way around and make sure that no part of the tube is stuck under the bead of the tire. Then when the tire is inflated check again to see that the tire edge at the bead is evenly seated at the rim edge on both sides (spin the wheel and watch this edge to check for any high or low spots). If there are any then deflate and determine the cause. Then reinflate. One common problem area is at the location of the valve - push the valve into the rim to free it from the tire bead before inflating.

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    bro
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    putting talcum powder on your tires and tubes before installing helps

    with some stuff

  5. #5
    Senior Member bmwjoe's Avatar
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    Quote Originally Posted by prathmann View Post
    The way you get the explosive sound and long gash in the tube is that part of the tube first escapes from the tire, then that part rapidly blows up like a balloon and pops. If the tire is undamaged then the tube must have escaped from under the bead of the tire. Either because it was trapped between the bead and rim on installation or because the tire bead wasn't properly seated in the little lip on the outer edge of the rim. (Other possibilities are a tire that's made a bit oversize vs. a rim that's a bit undersize, or a defective bead - but those seem unlikely when you have multiple failures.) When you install the tire and tube on the rim go all the way around and make sure that no part of the tube is stuck under the bead of the tire. Then when the tire is inflated check again to see that the tire edge at the bead is evenly seated at the rim edge on both sides (spin the wheel and watch this edge to check for any high or low spots). If there are any then deflate and determine the cause. Then reinflate. One common problem area is at the location of the valve - push the valve into the rim to free it from the tire bead before inflating.
    +1 I have had this happen a bunch of times until I figured it out. Mount the tire and inflate it to like 5 psi then work the bead into position with your fingers. Make sure it is even all the way around the wheel. It is easy to mess up.

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    Dog is my co-pilot 2manybikes's Avatar
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    You are pinching some of the tube between the edge of the tire and the wheel. One needs to carefully go all the way around each edge, and push the tire in a little and be sure you can see metal. Only then do you put more air in the tube. The long rip and delayed explosion are typical symptoms of this. It is not unusual, lots of new tire changers do this. Practice and patience will help. Inflate the tube just a little to get it up into the tire. Then as you get close to the
    last part of the bead to go over the rim, deflate the tube a little. Pump in a few psi, then visually compare the line all around the tire on both sides that is near the wheel. If one section of the line moves away from the wheel that is a sign that there is pinched tube in there.
    [SIGPIC][/SIGPIC]

  7. #7
    Senior Curmudgeon FarHorizon's Avatar
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    I've done the same thing. If you aren't REALLY careful on installation, you can pinch the tube between the tire bead & the rim. The advice from @prathman to inflate to only 5 psig & then check the seat is excellent. I normally then deflate & look closely again. If everything looks good, I inflate to 20 psig to check the valve position in the rim. If the valve is at an angle, I deflate again & rotate the tire/tube on the rim until the valve is straight. Third try goes to full pressure.

    Since I began the "three-stage" inflation method, I've not pinched a single tube in many, many tire/tube swaps. Experienced guys can probably do as well with a single check @ 5 psig, but I'm a klutz!

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    Senior Member franswa's Avatar
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    Thanks for all the replies. I thought I was good at installing tubes and tires. Been doing it for a while without incident. Perhaps the Paselas require some extra finesse.

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    Senior Member zandoval's Avatar
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    Quote Originally Posted by FarHorizon View Post
    ..."three-stage" inflation method...

    Right up there with the measure twice or more then cut once...

  10. #10
    A Roadie Forever 79pmooney's Avatar
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    It can also be that the tire has slipped off the shelf into the center area of the rim. That means the bead will be looser on the opposite part of the rim. It can then be pushed up the rim and off. The tire will appear to be expanding as it moves up the rim. When it slips off, you get exactly what you describe.

    Note that dropping the bead off the shelf is commonly done to ease the bead tension at the opposite side to mount tight tires. No problem but you have to make sure the bead is pulled back onto the shelf before inflating.

    This can also happen with old or poorly made tires where the bead is too stretched to fit tightly enough. There are tires and tire rim combinations I will not use.

    Ben

  11. #11
    Morton Nagrom_'s Avatar
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    "I don't know how to change a tire."
    Quote Originally Posted by seau grateau View Post
    No offense but you're an idiot.
    PedalRoom

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    Senior Member franswa's Avatar
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    Quote Originally Posted by 79pmooney View Post
    It can also be that the tire has slipped off the shelf into the center area of the rim. That means the bead will be looser on the opposite part of the rim. It can then be pushed up the rim and off. The tire will appear to be expanding as it moves up the rim. When it slips off, you get exactly what you describe.

    Note that dropping the bead off the shelf is commonly done to ease the bead tension at the opposite side to mount tight tires. No problem but you have to make sure the bead is pulled back onto the shelf before inflating.

    This can also happen with old or poorly made tires where the bead is too stretched to fit tightly enough. There are tires and tire rim combinations I will not use.

    Ben

    Thanks for your response, Ben. Sounds like what most likely occurred in my case. I have to remember that each tire/rim combo is going to be different and it is evident with this pair.

  13. #13
    Grumpy Old Bugga europa's Avatar
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    Quote Originally Posted by franswa View Post
    Thanks for all the replies. I thought I was good at installing tubes and tires. Been doing it for a while without incident. Perhaps the Paselas require some extra finesse.
    Some tyres are worse than others, even within the same brand and model. It also depends on the life they've had before you get it. Sometimes you look and feel like an expert, others like a TV soap opera parody.
    I had a good bike ... so I FIXED it

  14. #14
    Senior Member GENESTARWIND's Avatar
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    Quote Originally Posted by Nagrom_ View Post
    "I don't know how to change a tire."
    good ol Morgan

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    Senior Member franswa's Avatar
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    Quote Originally Posted by europa View Post
    Some tyres are worse than others, even within the same brand and model. It also depends on the life they've had before you get it. Sometimes you look and feel like an expert, others like a TV soap opera parody.


    I went a little slower this time and it seems to have worked. Now I know, and knowing I'd half the battle.

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    Morton Nagrom_'s Avatar
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    Quote Originally Posted by franswa View Post
    Now I know, and knowing I'd half the battle.
    Might be more than half.
    Quote Originally Posted by seau grateau View Post
    No offense but you're an idiot.
    PedalRoom

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