Has anyone ever heard of this? I'm not sure how it happened, but when I went to replace my tire today, I found that I had two stem lock nuts on my valve. One inside the rim and one in the normal place. Not sure if the shop did this for me a awhile back or if I did this absentmindedly last time I changed it. Anyway, it didn't cause any problems and I put at least a few hundred miles on it like that.

Any reason to do that? Thanks!

  • 1
    Does your rim have a 6mm Presta sized hole, or a 8mm Schrader sized hole? Could be the first nut on was in lieu of a grommit ?
    – Criggie
    Commented Apr 30, 2016 at 21:44
  • 1
    Yeah, the usual reason for that is a hole that's too big for a presta tube and using the nut to take up some space.
    – Batman
    Commented Apr 30, 2016 at 23:27
  • nope. Rim has the proper presta hole...
    – ss ulrey
    Commented May 1, 2016 at 0:34
  • 7
    Then assume whoever installed it was drunk.
    – Batman
    Commented May 1, 2016 at 1:21
  • 1
    Assuming the rim is drilled for Presta, there is no reason to do this, and doing it could potentially lead to premature tube failure. Commented May 9, 2016 at 18:02

3 Answers 3


It is a commonly used quick and dirty fix when you don't have a purpose-built grommet to install in a rim cut for a Schrader valve. It may also not be a terrible idea if, for whatever reason, your Presta-hole rim has a burr or sharp edge and you want to avoid any possibility of problems with that.


No, there is no reason for that type of installation unless the whole in the rim is sized for a Schrader valve, rather than a presta valve.

It is, as you found, unlikely to cause an issue though.


I put one inside and outside after having a few failures of the valve stem tube connection point. It appeared that the stem was being pulled away from the tube Now months of use later no issues

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