Which bike? My K9 and Mastiff (both 06) had them replaced a few years ago and they're both perfect. You have to adjust the height of the rear mount so it's really tight when you slide the tank forward onto it, then the front mounts just hold it down and from sliding back. The rear mount may need to go down a turn or two. I just put my mastiff back together last night after a fresh paint and ended up turning the rear mount down a half turn, which holds it a lot better. Really shove it forward hard, then do the front mounts. I even put a little WD40 on it so it'd slide forward all the way.