Sounds like it is the crack pipe adapter I'm using then. I did a quick check and the opening on my disc is 70mm for the valve stem. There is a 32mm stem length butyl tube in there now. If I added another 20mm on top of the current stem in there (to mimic a 51mm tube) that leaves me with less than 20mm of clearance to get an crack pipe in there.

I have a Topeak one (Schrader actually...But that was my mistake on ordering) and it wouldn't fit with any tube larger than 36mm valve stem length icluding a presta-schrader​ adapter easily. But, the shape of the correct presta only crack pipe wouldn't fit either I think as the profile doesn't appear that much less "high" than the one I got.

This is what the one I use looks like.

Much lower profile than mine.

x2 or x3. The Vittoria Latex tubes are the ones I would go with. You can get the Michelin shorter but they don't have removable valve cores and the valves do break. I have Jet+ Disc and have used numerous crack pipes, and even a full pump head w/o issue.

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