njkayaker: If you spin your wheel slowly, until it comes to rest, the light side will be up. If you put weight on the light side, it will be closer to being in balance (hard to get it perfect). Placing the magnet (weight) closer to the rim puts it where it has more effect on the imbalance. I have done this on several wheelsets, and have had good success this way. I even tripled my presta valve lock nuts in conjunction with magnet, and got that wheel nearly perfectly balanced. It works.