I used to have trouble with spiderwebbing on the back, a real mess. After a visit to the local LYS, where they had the same trouble after a try on their high end model even after playing with tension and thread changes. Slowing down on curves and putting a teflon washer called Magic Bobbin Washers in the bobbin, most of the problems have been resolved. I keep the washers in the bobbin case all the time now.