Not quite a remix of the Valve stabiliser for carbon road bike wheels as I modeled it from scratch, but definitely an inspiration, so wanted to give the credit.

Sometimes a Presta nut doesn't sit quite right on a rim profile, generally because of a curve in the rim. I've printed RodLaird's design before, but I don't have carbon aero rims, so it doesn't fit quite right. Working on a fat bike wheelset with a curved center channel, I thought of this design and thought I should give a try at modeling a parametric version.

Mine isn't as fancy as RodLaird's as his has nice, sculpted transitions, and mine is a straight loft, but if it's printed smaller, that's less obvious.

To change the design to fit your rims properly, you'll need Fusion 360 and the F3D file. You can measure the curvature on the rim with any of the awesome radius gauges available here on Thingiverse, then feed that into the third sketch. The 280mm dimension came from the Bontrager 650b fat bike wheel I was working on, but it isn't going to make a large difference for most rim sizes, so you can probably leave that alone. If you want to measure, measure from the hub centerline to where the valve comes out of the rim.

Also, feel free to adjust any of the values in the first two sketches. All I ask is that you print your makes or post your remixes!