Problem With Rear Wheel Tyre Deflating Going Through Many Inner Tubes

Discussion in 'Cycling Equipment' started by cowlover, Nov 22, 2015.

  1. cowlover

    cowlover New Member

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    This problem has been going since the spring. In the spring I dusted off my bike and got it out the shed, then I had a slow puncture and I mean slow it took about a week to go entirely flat. I lived with that for a few months pumping it up before setting off. Then I decided to get a new inner tube and broke two inner tubes whilst inflating it they just went pop! Eventually I managed to get one in and inflated but noticed there was a bulge around the valve but decided to go cycling anyway and sure enough on every revolution I felt a bump but the problem seemed to go away the further I cycled and I got home and put the bike away. And now 2 weeks later I have just got the bike out and seen the tyre is completely flat and has a fast puncture. I've been using continental conti tubes race 28 (700c) and have been checking the wheel for sharp or foreign objects when changing the tube. Is there something obvious I'm doing wrong here? I don't want to keep forking out money for new tubes all the time and its really beginning to take the fun out of cycling for me. Any advice please? Am I using the wrong inner tube it looks the right size.
     
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  2. oldbobcat

    oldbobcat Well-Known Member

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    You're probably pinching the tube between the tire bead and the rim, but first things first. Before you install another tube, check that there's nothing sharp on the inside of the rim or the tire. Now, before you install the new tube, put a couple puffs of air into it. This will give it shape as you stuff it between the tire and the rim. Next, start pushing the bead into the rim, starting opposite the valve. As you do this, make sure the tube is completely inside--if you can see a pocket of tube sticking out under the bead of the tire, you'll need to work it in by "massaging" the tire or starting over. If you don't, air will enter this pocket when you inflate the tire, leading to a flat. Now, as you get to the valve, keep working the tire into the rim just using your hands. Let some air out if necessary. Next, push the valve into the tire to seat that. Inflation will push it out again.

    Now, before you inflate, check your work. Go around the wheel, pushing in the sidewall and looking for pockets of tube sticking out. Both sides. If all clear, inflate.

    Regarding tube size, look at width as well as diameter. You don't want to stuff a 32mm tube inside a 23mm tire.
     
  3. BobCochran

    BobCochran Well-Known Member

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    Also, if the tire has been around for a while, I suggest replacing it with a new one. My old Michelins were getting really thin in the tread. I had one flat at my day job and it took me hours to fix it. I learned! I replaced both tires with new Schwalbe tires and Serfas tubes. I'm pretty happy with them.

    Bob
     
  4. cowlover

    cowlover New Member

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    I'm going to go tubeless I think, I must have gone through 7-8 tubes for this rear wheel this year trying to sort it, I've had enough. I have one tube left which I may or may not give one last try with. Also my tyre is new I sorted that out in the spring.
     
  5. Froze

    Froze Well-Known Member

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    What kind of bike is this? You say the bulge was around the valve? Makes me wonder if you have a mountain bike or an older bike that uses Schrader valves, and you bought Presta valve tubes because the size marking on the tubes said it would fit a 27" wheel, I know that sounds lame but sometime we run into some lame stuff here. It's also possible that you're using too narrow of a tire for the rim which makes it very difficult to install a tube without pinching it, if this is the case, or not sure at least check it by trying to find the original specs on the bike and what size tire came with it and buy that size of tire.

    Normally I would think you're pinching the tube but since it apparently is happening at the same spot, the valve, leads to the below explanation. A small gash (tear) in the tube vs a small hole is indicative that you are pinching the tube. But first just to be safe check your rim tape to make sure it's not frayed or the hole for the stem in the tape is not centered correctly over the hole on the rim; if you have any doubts about the tape get new tape and leave your doubts behind. If you get new tape and are not sure of the size simply take a rim down to your LBS and have them get you the right width and thickness.

    If the valve situation I mentioned is not the case then you're not seating the tire correctly where the valve is. Use a talic powdered tube to make it easier for the tube to slide into position, either buy one pre talic'd or do it yourself with baby powder, simply but some powder on your hands and thread the tube through your hands so that you get an even application of the powder (be careful where you do this because the powder can get on some stuff that may be hard to get off). First repair the tube unless the hole or rip is at the valve stem then you need a new tube.

    Then see this video: https://www.youtube.com/watch?v=TnP6coXzbLY

    Next with your hands pinch the tire inward all around the rim to make sure the tube isn't pinched between the tire and that the tire is even on the rim, most tires have a small ridge (they discuss in that video) that is suppose to be just above the rim and visible all around the rim and on both sides of the tire for a guide. T

    The rest I'm going to tell you the video leaves out, but how he does it is correct once you get use to installing tires and tubes then all this double checking isn't necessary. Double check the stem by gently pushing it in and pulling it out, it should move freely, this will indicate the tube is not pinched in that area. Inflate your tire to about 45 psi then deflate, this helps the tube to untwist and to set properly; then pump it up again to about 20 psi check the ridge line to make sure it's even with the rim on both sides, if not you simply press the tire inward and it should move into the right position when you let go, or you may have to pull the tire a bit if the line is below the rim or push it down if the tire is too far above the rim, then continue to pump to about 35 and recheck, then pump whatever pressure you desire, once there recheck the tire to make sure the ridge line is even around the entire tire. If by chance the ridge line is hidden or too high in one area you'll need to deflate the tire down to about 20 psi and rework the tire in that area to get it right.

    Once you get use to knowing where the tire needs to be it will become faster to do then what appears to be a long process of checking and pumping and rechecking will be eliminated like the seen in the video.
     
  6. mpre53

    mpre53 Well-Known Member

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    The first thing I would check is the rim tape covering the spoke holes. Make sure that a spoke end isn't pushing through. Then, very carefully, go all around the inside of your tire. It doesn't take much to cause flats---a hair thick piece of wire can do it. Something is causing your flats. That many tubes won't have a defect/go flat on their own in just half a year. It's either your installation, or something in the tire or rim.

    If you pinch a tube mounting the tire, it probably will blow soon afterwards---maybe even as you inflate the tire. Or on the first hard bump after you resume the ride. But not always.

    As far as tube size goes, you should try to match it to the tire/rim, but a 700c tube is fine in a 27" tire, and you can use a smaller tube in a wider tire. I've used 23 mm tubes in the 27x1-1/4" tires on my old Schwinn, when they were all I had on hand. 32 mm would have been the correct size.
     
  7. cowlover

    cowlover New Member

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    Its a satellite Jamis road bike bought and ridden in the UK. The tyres are 25-622/ 700 x 25c and the tubes I'm using are Continental Conti race tubes. (Theres a whole load of numbers on the box so I'm not sure what they mean or which are relevant so here they are as positioned on the box) :-

    Race 28 (700c)
    20-622 > 25-630
    27 x 3/4 > 27 x 1.00
    700x 20c > 700 x 25c

    S 80mm Presta (the bike was presta valve when I bought it new in 2012)
     
  8. mpre53

    mpre53 Well-Known Member

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    The numbers just describe the various size tires that your tubes are designed to fit. 700c and 622 mean the same--700c tires are 622 mm. Same is true of 27. 27" is 630 mm. In other words, you have 700c tubes that will also fit older 27" tires, and are made to fit tires between 20 and 25 cm wide (or 3/4 to 1 inch wide tires in older 27" tires). Your bike has 25 mm wide tires. But you can also use them in wider tires, if you have to.

    Your tube stems appear to be 80 mm long. Those are LONG stems, probably designed for deep CF rims. No problem running those in regular alloy clincher rims. They work fine. They just look strange.
     
  9. cowlover

    cowlover New Member

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    My Goodness thats confusing, but thanks, I'll give changing the tube one last shot tomorrow.
     
  10. BobCochran

    BobCochran Well-Known Member

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    @cowlover "one last shot" is the sure and certain sign of someone who needs to try again...and again...and again. Don't try "one last shot". Try as many times as it takes to succeed. 10 times, 100 times, 1000 times, 10,000 times, it doesn't matter: you keep trying till you succeed. Success is rarely instant. If you really want to succeed...you will keep on trying.

    Thanks

    Bob
     
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  11. cowlover

    cowlover New Member

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    Ok putting in my last tube now and the same situation seems to be arising. When I pump up the tyre slightly after putting in the new tube the area around the valve doesn't inflate like the rest of the tyre its soft not hard. Is this a sign of it pinching? Looking inside it looks as if the tube sticks out a little here at the valve but nothing major. In any case I cannot seem to get the tube to hide perfectly in the tyre in this area like with the rest of the tube. Also inside the wheel I noticed the numbers HP-702B 700C - 18mm . Is 18mm the recommended width of tube for my wheels? If so am I using to wider a tubes?
     
  12. Froze

    Froze Well-Known Member

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    Is it possible for you to take a clear close up picture of your valve stem and rim hole?
     
  13. cowlover

    cowlover New Member

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  14. Froze

    Froze Well-Known Member

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    Try mounting the tire 180 degrees from where you normally place it on the rim and reinflate. Maybe there's a problem with the tire, if the tire bulges on the opposite side than its the tire.

    If it still bulges at the stem the only other suggest is the rim hook that locks the bead of the tire onto the rim has been deformed enough not to let the bead seat thus the tube simply pushes the tire away from the rim.
     
  15. BobCochran

    BobCochran Well-Known Member

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    I've never seen a valve like that. Normal Presta valves are threaded so that you can screw a nut on the outer body of the valve and secure the valve to the wheel. The outer body of your valve looks smooth rather than threaded, and the valve itself is pretty long, too. So this is a new type of valve for me. I'm not sure what I can usefully add that will help you.

    Bob
     
  16. Froze

    Froze Well-Known Member

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    Bob, that stem is perfectly normal except it's way too long for the rim but that won't cause any problems other than make it easier to bend when pumping. A lot of long stem tubes are smooth all the way down, and you really don't need the nut to secure the stem to the rim, I haven't used those nuts in over 40 years.
     
  17. oldbobcat

    oldbobcat Well-Known Member

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    Aha! that bulge in the tire in beneath the valve is the tube being pinched between the bead of the tire and the bead seat of the rim.

    Do this. With the tire deflated, push the valve stem into the tire and wiggle it around a little bit. Now re-inflate. The pressure inside the tube will push the valve out a bit, but the tube will be fully seated inside the tire. This is common with narrower tires.
    Aha! that bulge in the tire in beneath the valve is the tube being pinched between the bead of the tire and the bead seat of the rim.

    Do this. With the tire deflated, push the valve stem into the tire and wiggle it around a little bit. Now re-inflate. The pressure inside the tube will push the valve out a bit, but the tube will be fully seated inside the tire. This is common with narrower tires.
     
  18. cowlover

    cowlover New Member

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    Yep thats sorted it, its strange I've never had that problem before unless these continental conti tubes are wider than what I usually buy, anyway thanks for the help.
     
  19. oldbobcat

    oldbobcat Well-Known Member

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    A photo's worth a thousand words. Glad I could help.
     
  20. Froze

    Froze Well-Known Member

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    LOL!!
     
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