I just bought a Trek Marlin 7 for my wife, and it came with Bontrager Kovee TLR wheels, with tubes inside them. I'm trying to convert them to tubeless, but am having issues finding valve stems that fit.

I looked up which stems I needed here: https://trek.scene7.com/is/content/TrekBicycleProducts/TK21%5FMISC%5FRimstrip%5FCompatibility.pdf
This says I need the Round Base 32mm stems: https://www.trekbikes.com/us/en_US/equipment/cycling-components/bike-tires/bike-tire-accessories/bontrager-round-base-tlr-valve-stem/p/W250324/

I bought some, and they do not fit. They hit the sides of the inner wall long before coming in contact with the bottom.
I also tried Stan's universal valve stems. They almost work, but have the same problem.
Has anyone had this problem?
Does anyone know which valve stems I need?

  • Clarify - it is a problem with the inside of the rim and the shape of the sealing flange of the valve?
    – Criggie
    Commented Oct 5, 2021 at 2:02
  • 1
    @Criggie That's right. The flange is too wide and doesn't fit down into the dip of the inner wall. Commented Oct 5, 2021 at 2:42
  • 2
    Are you using the Bontrager TLR rim strips, and putting the rim strip on first and then the valve through the strip and into the valve hole? Commented Oct 5, 2021 at 5:51
  • The flange should have nothing to do with the rim’s inner walls. It merely sits on the flat part of the rim strip, which is elevated way past where the rim’s dip should be a problem. As Nathan said, rim strip first, then valve.
    – MaplePanda
    Commented Oct 5, 2021 at 6:07
  • Oh I am an idiot. I cut the hole in the strip that came on the wheels bigger so the valve stem could sit down against the rim. Commented Oct 5, 2021 at 12:24

1 Answer 1


Trek/Bontrager TLR wheels, rim strips, and valves are designed as an integrated system. The rim strip is chunky compared to a conventional (i.e. Stan's-like) tubeless tape, and is designed to lock into the rim precisely, and then help create the bead lock area on its top side. The valves have a simple flat flange profile and are made to lock into their spot on the Bontrager rim strip, somewhat differently than how most tubeless valves either wedge into place with a conical section or attempt to make a broad contact area of squashed rubber as in the more oblong type.

I can't speak to how successfully one can mix and match different other-than-intended rim strips and valves on the different Bontrager wheels. There are lots of them. I have seen other brand valves with a conical rubber base like Stan's and WTB be able to substitute for the Bontrager successfully ones in a pinch on wheels with TLR strips.

In your situation, if the rim extrusion profile is one where it seems to not want to take anything else but a TLR strip and valve, and plus you already have the valve, you're probably better off buying another TLR strip to replace the cut one. Conventional tubeless tape is thin so typically won't do anything to change the rim profile and allow a different valve choice. One can imagine different ways of re-profiling the valve rubber to fix the situation or building that area of the rim back up, but you may only be in for more frustration when you try to get it to seal, so it depends on whether you're willing to experiment.

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