Feedback Sports Flop Stop Handlebar Holder. The Flop Stop is a clever service upgrade for the most demanding and home bike mechanics alike. The Flop Stop is an adjustable solution to keep your handlebar position static while you manage detailed bike maintenance like brake bleeds handlebar wrapping and full assembly to name just a few. This handlebar holder also works great when storing road bikes fitness bikes mountain bikes and e-bikes to keep the front wheel straight.