290 or 295mm belt for 15/36T

Hi!

Im going to give a 3D printed (reinforced with metal rods) mount a go. If it brakes, thats fine, I’ll use the waterjet at school and make an aluminum one. Found here:

Center to center distance is 77mm, and https://www.bbman.com/belt-length-calculator/ is giving me a length of 295mm with a 36T/15T setup? Why not 290mm? Are bbman not recommending 290mm since they don’t have it in stock or whats going on? :slight_smile:

Thanks!