PMW EC34/EC44 Head tube profiles

Thanks for the suggestion. I will plan to account for those.

I could answer this question a few different ways depending on your expectations.

The answer that I think will work for most is that you can already model these headtubes in BikeCAD. Below is a diagram of the 120mm headtube (HT0510 for Ti or HT2510 for Steel). In the animation, I've overlaid a headtube in yellow that you can represent by setting E=25, d=37, B=70, ∅=47.2 as shown below. The 120mm length can be specified in the Primary dimensions dialog box by selecting the Front center / Head tube length option.

You can model any other length using the same specs above except set B = Headtube length - 50mm. For convenience you can save them to your menu of standard head tubes as described at bikecad.ca/standard_parts_library.

If you are noting that these head tubes have a 4mm band of extra material at the top and bottom edges of the tube and that the cross section is not made of perfectly straight edges but rather follows a bit of a sigmoid curve, I regret that I won't be able to capture these nuances in BikeCAD at the moment. The next update will feature an export to FreeCAD option that will export dropouts, yokes and gearbox bridges as 3D STEP files in all their intricate detail. In the future, I could see exporting headtubes as individual STEP files to capture all these nuances if this is the kind of thing you are looking for.