Well, no two tubes the same with the mold lines to use as a cutting guide... one belt is 69mm, another is 72mm... that I recall off the top of my head. I measure throughout the entire length to find the widest area, the cut varies 1 - 2mm in width... not perfectly true, but that shouldn't pose any problems.
Tight enough that I could probably play a tune from it.
If the bearings I got fail, then I'll install bigger bearings.
