The serrated edge should embed into the seat lug to prevent movement/spinning.
If that's not happening your hole is shagged or too large.
Purchase a bolt with hex on both ends or with a notch on one, if the lug is keyed.
[URL="http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=BZwwCs8KbL2XIM&tbnid=Vw_kdqROwS_XGM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.rakuten.com%2Fprod%2Fritchey-wcs-one-bolt-road-bicycle-seatpost-mast-topper-30-25-x-70mm-x%2F240621746.html&ei=9eYTUozfO4rG0QW69IDYDw&bvm=bv.50952593,d.ZGU&psig=AFQjCNEkgDCfThgjelfK4je5dLTgXP34wg&ust=1377122332865245"][/URL]
@dmczone started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
The serrated edge should embed into the seat lug to prevent movement/spinning.
If that's not happening your hole is shagged or too large.
Purchase a bolt with hex on both ends or with a notch on one, if the lug is keyed.
[URL="http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=BZwwCs8KbL2XIM&tbnid=Vw_kdqROwS_XGM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.rakuten.com%2Fprod%2Fritchey-wcs-one-bolt-road-bicycle-seatpost-mast-topper-30-25-x-70mm-x%2F240621746.html&ei=9eYTUozfO4rG0QW69IDYDw&bvm=bv.50952593,d.ZGU&psig=AFQjCNEkgDCfThgjelfK4je5dLTgXP34wg&ust=1377122332865245"][/URL]