This is a parametric HTD5 pulley made in Fusion360. The design is partly customizable by changing the number of tooth and width of the pulley. I have made some comments on the other parameters also, so for the mathematically inclined there should be no problem to modify the other parameters as well.
Please note that I have assumed bend-point of belt to be in the middle of the belt. If you want a tighter fit, change outerCircleDia "-(3.8-2.06)" to a slightly smaller number, to reduce the offset.
To change parameters in the Fusion360 model, download it from the provided link(generated by the share-button in Fusion360 and open it in Fusion360. Then go to modify->change parameters. Here you can apply any changes you want.
Model dimensions is based on and designt methodology is greatly inspired by this guide by Richard: https://capolight.wordpress.com/2018/06/16/full-guide-to-creating-a-htd-timing-pulley-in-cad-fusion-360/
From his site i sourced dimension data was inspired by his design strategy. Thanks :)
The parametric model can be downloaded from this site:
I have printed this is both 20 and 30 teeth with no other changes than the numTeeth parameter. Please let me know if anything may be improved.