As discussed in postings above, belts like all manufacturing are not precision but will have + or - tolerances in their actual lengths. It sounds like you have one that is at the end of the - tolerance, or stated another way, the smallest allowed by the tolerance. If it is that difficult to slip on you may find if you do get it on that it is way too tight to operate properly putting too much stress on the shaft or the motor. You may have to remove the motor and file some slots in either the mount or the motor base to allow some adjustment before you can get it assembled without damage to the tool or the belt. Even if you go for a link-belt you will need some adjustment to compensate for the segment lengths as you can only adjust the belt by one segment at a time.