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  1. #1
    spins pedals Zomar's Avatar
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    I came home to a 5-6 inch rip in my tube.

    This is my first flat tire...

    I have alex rp15f rims, 700x23 kenda kontender tires, a avenir tubes

    So last night I was riding my bike and the pressure was really low, so I filled my tires to the recommended 125psi. I road around for a bit and everything felt great. I brought my bike back into the garage and went to bed. The front wheel has been a little out of true for a while but not too bad. Everything was peachy.

    So then I go to work the next morning and come back and decide to go for a bike ride. Turns out my front tire is flat! The front tire had been pushed so that it was partially off the rim. I tried to reset the tire and fill up the tube but it didn't work. A FLAT I was dreading this...

    So me being far too hasty, grab two rulers and use them as tire levers to take off my tire completely. Then I pull out the tube and there is a ~5 inch long cut along the side of the tube. I later looked at my tire and it appears that maybe the beading on a small segment was partially worn away, but I can't tell for sure and I can't match this with the location of the rip because I noticed it later. The top of my presta valve cap is missing as if all of the air violently rushed out from the valve and blew a hole through it (the side walls of the cap remained screwed down).

    I don't think I ripped the long cut into the tube with my makeshift tire levers, and I don't see anything that would have caused the flat. Like I said, when I put my bike away it was fine, when I went to get it the next day the tire had come off and there was that 5-6 inch cut in the tube. It probably got 30 degrees warming out after I filled the tube, so perhaps the air expanding caused a problem? But my back tire appeared to be fine. I read that long cuts like that only can happen if there is a problem with the tire itself? Is this true? What should I do?

    I'm afraid if I just replace the tube I might get another flat right away, but I don't want to replace my tire/frame/etc if I don't have to. I plan on taking the wheel, tube, and tire to a bikeshop tomorrow for assistance, but I'd love everyone else thoughts especially before I buy anything. Could the wheel being out of true lead to this?

  2. #2
    Senior Member
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    check the rim to see if you have dinged it and flattened part of the lip that grips the tire. If not you are probably right about he tire bead being worn. Either way the tire slipped of the rim and the tube ripped from the escaping air. Only other though is if you recently replaced a tube you might have pinched the tube between the rim and tire. Then it finally slid off when you jacked up the pressure.

    Always place a the label at the stem and you can check placement easier.

    There are several discussions here on blowing tires in a hot car at high pressure. The science seems to indicate it is a none factor. Hence the heat is not an issue.

    Unfortunately you did not get the thrill of the explosive slip that some times occurs with a bang.
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  3. #3
    Senior Member DannoXYZ's Avatar
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    When installing the tyre, you pinched the tube between the tire and outside edge of the rim. That's where the tube bulged out and blew.

    Don't use tyre-levers of any kind. Technique with hands is all you need. Then before pumping up the tyre, pull it away from the edge of the rim so you can inspect the gap between the rim and tyre. Make sure no tube is visible. Work your way around the ENTIRE TIRE on BOTH SIDES and make sure no tube is visible. Only then should you pump up the tyre.

  4. #4
    cab horn
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    Quote Originally Posted by DannoXYZ View Post

    Don't use tyre-levers of any kind. Technique with hands is all you need.
    Gimme a break.

    Like all tools, they are good when used properly. Don't avoid tire levers because that's the "macho" thing to do. Learn how to use them properly and you'll change out tires with zero risk of pinching the tube faster than anyone using bare hands can.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  5. #5
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    It is a common problem for the bead of the tire to not be set evenly around the rim. Most tires have witness lines very close to the edges of the rim that make it easy to check. Where the bead is high especially at high pressures, the tube can start to slip out and then go blam.

    Especially since "the front tire had been pushed and was partially off the rim" it sounds like this is what happened. It is also the only way I've ever had of getting a gash in the tube the size you mention.
    mainlytext.com/bike.html Bicycling in winter, the entertainment version

  6. #6
    Space Dust
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    Quote Originally Posted by Closed Office View Post
    It is a common problem for the bead of the tire to not be set evenly around the rim. Most tires have witness lines very close to the edges of the rim that make it easy to check. Where the bead is high especially at high pressures, the tube can start to slip out and then go blam.

    Especially since "the front tire had been pushed and was partially off the rim" it sounds like this is what happened. It is also the only way I've ever had of getting a gash in the tube the size you mention.

  7. #7
    Senior Member BCRider's Avatar
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    Quote Originally Posted by Zomar View Post
    ...So last night I was riding my bike and the pressure was really low, so I filled my tires to the recommended 125psi.....The front wheel has been a little out of true for a while but not too bad......
    Getting a blowout of this sort is typically due to the tube being pinched between the tire's bead and the side of the rim's tire channel. It may be fine for a while but it seems that eventually the pressure continues to herniate the inner tube out and finally it has enough pressure to lift the bead up so it slips off the rim and then KABLOOEEE the tube blows out with a long rip like this. I've had it happen a couple of times over the years and one time it was good for about 10 minute and the other time for a little over an hour. You got more than that out of it but it's the same method of failure.

    When you rode the bike with the low tire pressure it must have been low enough that it allowed the tube to work around the bead to clincher connection and sit under the bead. THe air pressure you used started to work on the "hernia" and eventually some time over the night or day the tire lifted off the rim and the tube went bang.

    The advice to push the tire inwards and check for tube hernias is a good one. I like to put about 5 psi into the tube when doing this. That's just barely enough pressure to feel it. This small amount helps to give the inner tube shape so you can sort of lift the bead and a potential hernia will snap back into the tire instead of coming out more when you massage the sidewall around such a spot.

    Get some tire levers. They are your friend and won't cut a tube like steel rulers will do.
    Model airplanes are cool too!.....

  8. #8
    spins pedals Zomar's Avatar
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    So I took it to the LBS. The guy there said the tire and rim looked fine. He said that my tire looked loose/thin for my rim and recommended that I not fully inflate to the tire's recommended 125, as that could more easily cause a blowout(?). He said I'd be safer at ~100psi or so. I road 10 miles or so after fixing my tire.

    Any thoughts?

  9. #9
    Insane Bicycle Mechanic Jeff Wills's Avatar
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    Quote Originally Posted by Zomar View Post
    So I took it to the LBS. The guy there said the tire and rim looked fine. He said that my tire looked loose/thin for my rim and recommended that I not fully inflate to the tire's recommended 125, as that could more easily cause a blowout(?). He said I'd be safer at ~100psi or so. I road 10 miles or so after fixing my tire.

    Any thoughts?
    Yeah- he's an idiot. You'll probably get a better ride at 100psi than 125psi with little or no penalty in rolling resistance, but a tire that won't blow out at 100psi won't blow out at 125psi.

    As to the "no tools" installation- I'm mostly with Danno. If you can get the tire on without tire levers, you should do this all the time. It takes a little practice and finger sensitivity, but you'll figure it out. Once you do that, you'll be much better off than if you keep pinching tubes with tire levers.

    (Danno- PM or email me. Know where I can get raw carbon cheap?)
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  10. #10
    Senior Member DannoXYZ's Avatar
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    Quote Originally Posted by operator View Post
    Gimme a break.

    Like all tools, they are good when used properly. Don't avoid tire levers because that's the "macho" thing to do. Learn how to use them properly and you'll change out tires with zero risk of pinching the tube faster than anyone using bare hands can.
    It's not macho, I worked in a shop for years and raced for 10-years and can't tell you how many people come in with this exact problem. The catch word is to use tyre-levers "properly". Rulers and screwdrivers have sharp edges that'll easily puncture a tyre. Even tyre-levers can pinch a tube and put holes into it.

    Here's a technique that'll work without requiring any machoness:

    1. with tyre & tube off the wheel, give the tube a little pump so that it's round, but just barely.

    2. insert tube into tyre and lay over rim.

    3. push one bead completely over rim

    4. stuff tube completely into tyre & rim so that remaining bead sits flush on rim-edge

    5. start pushing over the remaining bead by hand

    6. that last 6-8" will be tough, DO NOT try to push up on the tyre at the middle of the unseated section, no human is strong enough to stretch the bead on a tyre.

    7. instead, push SIDEWAYS on the tyre at one of the two spots that wraps up and over the rim-edge; you don't need to stretch the bead this way, just push it sideways.

    8. The last bit 3-4" may need tyre levers, to do this cleanly, the tyre lever must never leave contact with the rim.

    9. place the tip of the tyre-lever on the rim-edge just under the unseated bead.

    10. GENTLY push it up under the tyre, BUT don't push it further than the top edge of the rim, you can feel it drop down slightly. Again, don't lose contact with the rim, this ensures that you never open up a gap between the lever and rim into which the tube and squeeze into and get pinched.

    11. next slide the tyre-lever sideways as far over as possible towards the area where the bead goes over the rim-edge; use your other hand to pinch the tyre onto the rim so that tyre doesn't slide off

    12. then GENTLY lift up the lever and push the tyre sideways; typically you don't need to raise the lever more than 90-degrees perpendicular/sideways relative to the rim

    13. pull lever out and repeat for other side. Remember, constant contact between the lever and the rim and don't poke the tip much further than the edge of the rim

    14. After the entire bead's on, let out some air from the tube and pull the tyre sideways to inspect the gap between the rim-edge and tyre, no tube must show the entire way around on BOTH sides.

    15. only after you've inspected the entire bead on both sides, then you can pump it up.

    BTW, depending upon your weight, 100 or 125psi will be a good -pressure. When I was a 150-lb racer, I used 100/110psi F/R on 23mm tyres. Later when I ballooned to 245-lbs, I used 120/125psi on 26mm tyres. Now that I'm down to 180lbs or so, I use 110/115psi on 25mm tyres.

  11. #11
    Senior Member Thumpic's Avatar
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    Quote Originally Posted by operator View Post
    Like all tools, they are good when used properly...........
    +1

    I've never pinched a tire using a lever. I have broken a lever or too; but that was more my fault than the lever's............

  12. #12
    Senior Member
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    slim box section rims can be really difficult to fit or remove tyres from.

    I use some liquid on the rim and tyre. soapy water.

    try not to use tyre levers as they will puncture the tube.

  13. #13
    Senior Member BCRider's Avatar
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    In my time I have come across a couple of tire to rim fits that were a little too sloppy and resulted in the tire not fitting securely onto the rim so it IS possible. It seems to come down to the tire being made slightly "loose" rather than the rims being bad. But if you get one of those sort of fits then it's best to plan on a new tire at some point in the future.

    Although I've most often seen this with folding tires it happened just a month ago while I was touring in Europe. My old tire was slashed by a bit of glass or other knife like shard and cut enough of the tire casing that the tube was trying to herniate out. A folded 10 Pound note solved the issue for the emergency. But a day later I bought a Schwalbe Marathon from a shop. When I got back to England from France I tried to mount it but it was so loose that I could almost toss the tire onto the rim. Even after seating it the tire still wanted to slip off unless I kept it centered. And yes I did check the size about 6 times to make sure I had not gotten a 27 inch by accident. It definetly said 700 on it but it just was a loose fit that would not stay centered. Perhaps it was a 27 that was mismarked? Who knows. It was left in a bus station in Scotland reluctantly and with disgust.
    Model airplanes are cool too!.....

  14. #14
    Banana seat Captain Slow's Avatar
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    I keep my daily ride in the sunroom, ready to roll at 5am. One evening, I was on the sofa in a nearby room, just drifting off... When suddenly, there's this huge, overwhelming BANG!!!! from the sunroom. Got my attention. Good thing I have a strong heart, otherwise the noise would've killed me. The tube in the rear tire (700X23, couple years old, no patches) just... popped. It split along a good three inches of seam.

    A friend suggested that it had committed suicide rather than endure another of my famous ride-with-no-end-in-sight Saturdays. Whatever. Tubes wear out, just holding air. I knew that, but I just kept on using these old ones.



    One tip that nobody mentioned...

    When replacing a tube, or tire, or both, inflate the assembly to about 40psi, and remove the pump.

    Spin the wheel in your hands, and sight along the tire bead on both sides... make sure that the bead is tucked in, and is close to even all the way around. (40psi won't seat it perfectly, but you shouldn't see any high spots, where the bead is visible.)

    Now, deflate the tube, and gently knead/squeeze the tire around its circumference. Finally, inflate to your preferred riding pressure.

  15. #15
    Senior Member gldrgidr's Avatar
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    Captain S.
    Can we see some better photos of your bananna bike?

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