2

I just had flat tube #4. Enough is enough.

Please examine the photo of my rim and the valve stem hole. Is the rim tape too far off of the edge? I had inflated the tire with more air, per the first post's advice responses. It had been working fine for nearly a week now.

Suddenly, pssssss and it's a hole at the valve stem. AGAIN. Just like the last two times. So am I just not pumping it up enough -- but if so why did it last so long -- or is it the rim hole rubbing away at the valve entry area and eventually cutting into the rubber at the valve?

I don't mind pumping it up...I have to do it manually, and fear for overinflation and potential explosion...but I can certainly pump it to the proper volume, as I have been riding on this tube for several days now.

Rim Tape Valve damage

4
  • We recommend that new members take the tour to make best of the site. There are three things about this problem that all point the same way: that rim tape is much more frayed than the first photo, indicating movement; the rim tape has moved; and tears in the side of the valve indicate movement. Clearly, the tube has not been pumped up enough to stop the tire+tube+rimtape from sliding around the rim. You just have to pump the thing up. Hard. – andy256 Sep 12 '16 at 1:31
  • 1
    I suspect that you're running the pressure too low. You need a pressure gauge of some sort to do it correctly -- you can't tell the pressure very well by "feel", and, in fact, if you can squeeze the tire at all with your fingers the pressure is probably too low. – Daniel R Hicks Sep 12 '16 at 2:35
  • 2
    If your rim tape looks like that and you can see that it has relocated, exposing the edge of the valve hole (which is one of the things it is designed to protect the tube from), then you should really get a new rim tape. You don't have to spring for the lovely Velox cloth rim tape (though it should easily outlast any non-disc rim), you can get friction fit rim tapes for a couple of bucks and change them when they wear out - check the rim tape every tire/tube change. Yours looks to have had a hard life, got wet a lot...not good. Do whatever you can to prevent a puncture ruining your ride... – kellbell Sep 12 '16 at 9:52
  • 1
    (If you have a standard "floor pump" it's virtually impossible to inflate a narrow to medium width tire to the point of explosion. Even with a good high-pressure pump you are working pretty hard by the time you get to 100psi, and few sound tires are apt to explode below 125-150psi.) – Daniel R Hicks Sep 12 '16 at 17:58
1

Rim strips, proper ones from a bike shop, last a long time and are immune to the wear shown on your picture. It looks like the strip left the hole exposed enough that the base of the stem was allowed to make contact with the rim.

My advice is to take off the rim tape. Clean the interior of the rim with acetone. Take some fine grit sandpaper (1600-2000 grit) and gently rub it into the hole from inside of the the rim. That will help smooth out any possible burs. Then install the rim strip (not tape) and for one last good measure use a tube that is one size smaller than you usually do. It is curious how the tape shifted. Perhaps the stem wasn't perpendicular. At any rate, the smaller tube would decrease the chance of this happening with no ill effects.

Good luck!

13
  • What is the benefit of a toxic, flammable, carcinogen such as acetone vs scrubbing with another cleaner? – andy256 Sep 12 '16 at 0:05
  • @andy256 Acetone is not classified as a carcinogen: toxnet.nlm.nih.gov/cgi-bin/sis/search/… – kmm Sep 12 '16 at 1:32
  • 1
    But rephrasing my original question: What is the benefit of ... acetone vs scrubbing with another cleaner? – andy256 Sep 12 '16 at 2:33
  • 1
    @andy256 You're a better man than I. To answer your question, acetone is a better solvent of non-polar molecules. These include complex hydrocarbons found in oils, glues, paint, etc. Scrubbing with water and a detergent would remove a good amount of the offending material. However, water is still a polar solvent and even with the inducements of a detergent it cannot be as effective as a polar solvent (such as acetone). An acetone wet cloth used as a wipe will do the job well. – user26705 Sep 12 '16 at 3:42
  • 1
    I've seen rubber strips on new bikes within the last 10 years, so the issue @DanielRHicks mentions is still an issue. I suspect you (B Team) buy moe expensive bikes than my family! – Chris H Sep 13 '16 at 7:59
0

I've suffered from similar issues in the past and found a couple of easy options for avoiding rim holes that saw through valve stems.

  1. Staying with Schrader valves. Move to a tube with a full metal valve stem such as Conti-Tubes.

enter image description here

  1. Moving to Presta valves. Move to Presta valve tube and use a rim hole adapter such as a Wheels Mfg Presta Stem Saver.

enter image description here

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.