Stick a scriber (or some other pointed tool) under the grip to make a gap. Insert the straw on a can of Liquid Wrench, or some other penetrating solvent and squirt some in there. The grip should twist right off; if not, repeat the procedure in a different spot under grip. Clean bars with alcohol to remove the solvent before installing your Ergons. Careful tightening the bolts on those GC2s... I busted one by over-tightening. If you don't have a torque wrench just tighten until you can no longer rotate the grips by hand.