It's not your job to go after tanks as Ashe. Those are not high priority targets. You kill squishy carries first. And LW is a nice item, and if the other team is really really heavy on armour, just go Black Cleaver.

i lold at whoever gets other boots than zerk greaves on ranged dps. i cant think of one ranged dps that doesnt get zeal/pdancer anyway later on and then gets in the breaking zone for movement...