Speed tanking is not overpowered.
Having said that, one of the strengths of speed tankers is their ability to dictate range. If you can take away that advantage by fitting a weapon system that can deal damage at multiple ranges that may swing the fight in your favor. Try piloting your ship in such a way that transversal velocity is minimized, and as a result DPS maximized. Fast drones (Warriors or Valkyries) will also usually be able to deal good damage to these ships. At the very least it may force them to disengage, allowing you to reposition for a second try or run away.
To kill the fast ships however, you need some way of locking them in place while you lay the hurt on. That is where it gets tricky. Webs and scrams are an option, but unless they make a piloting error you will struggle to get in range. The same goes for neuts. Try overloading and manual piloting to catch them off guard. With some luck you might get a neut, web or scram on them and that will certainly give you the upper hand.
Ultimately though, as long as they have the speed advantage and you're unable to get tackle on, they can choose to disengage and run away if they find they are loosing the fight. A fast ship set up for kiting is just the paper to your rock I'm afraid.