I got one of these air wedges for hanging doors. It gives about 2 - 2½ inches of lift so isn't enough on it's own to lift a wheel (for me anyway). But used on top of a bit of wood, a few pumps raises the wheel to exactly the right height.
Having said that, I can't remember the last time I used it - the rear is a single-sided swinging-arm so is easy anyway and for the front, I've been using the Mr Gazza toes method as I can't be bothered to dig out the wedge.