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My rims have a couple of small holes along the edge of the flat at bottom of the bead (just above the valley). I assume they are there to vent the space between the tube and the tire, i.e., to let air out as the tube is inflated, but I don't see why that should be necessary. Maybe they are manufacturing artifacts?

The holes are small -- about a 0.1" (2.5 mm) in diameter. Should I cover them with rim tape to protect the tube? That will require wider rim tape--wide enough to get into the bead area. Seems bad.

  • Do you get punctures in that area of the tube? If not, I wouldn't worry. – Criggie May 2 '18 at 10:00
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    I don't get many rim tape flats. In my experience, if an edge is barely exposed, it could take weeks or longer to get a flat. Sooner at higher inflation pressures (voice of experience. ;^J ) I'm wondering if the (uncovered) vent holes are like barely exposed spoke holes. The plastic tape that came on the rim covered the holes, but it was too wide (I think--that's what I'm asking. The original tape interfered with the tire bead, so it got pushed around while dismounting/mounting tires. It was particularly noticeable while checking that the tube wasn't caught under the tire before inflating. – riderBill May 4 '18 at 23:42
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Schwalbe's Q&A Which rim tape should I use? advises a tape that covers the rim bed over the full width. According to the pictures, only the floor of the bead area should be covered. I guess this is in agreement with the ETRTO standards.

  • Thanks for the link. I took a quick look--different than what I was thinking. I thought the tape was not supposed to extend under the tire bead, lest it prevent the bead from seating properly. I'm in a bind for time. I'll have get back to this later. – riderBill May 5 '18 at 0:04
  • I'm thinking part of it might be terminology.... "under" the tyre bead in this context means "between the hooky part of the sidewall of the tyre, and the upstand of the rim where it hooks onto the bead of the tyre" as opposed to "between the edge of the tyre and the horizontal bed of the rim" – Criggie May 5 '18 at 4:48
  • Yes, the terminology is tricky; pictures would be useful. After looking around, I think your answer is right on the money. If the tape extends all the way to the "wall," the tire can't catch on it, and it shouldn't make mounting any harder, since the already mounted part of tire bead should be in the valley anyway. And it will cover my vent holes. Unfortunately, the width required to go full width, or wall to wall, isn't easy to measure, nor is it likely to be one of the two or three widths on the rack. Not the width of the OEM tape, either [sigh]. But at least I know that to look for now. – riderBill May 15 '18 at 6:21

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