Finally I had to replace my tires. The old set was Bridgestone BT-57 and lasted 10400 miles. Now I can try the Michelin Pilot Road that everybody was talking about as they're supposed to be much better than the Bridgestone BT-57. We'll see...

I put a piece of wood under the engine and used a scissor jack to jack up the front wheel. Now both the front and the rear wheels are off the ground.