A 55 gram iron shaft is on the far side of crazy. Like others have said, there is no way a shaft can be produced at 55 grams and have any amount of stability whatsoever. That is either a shaft option for women and seniors (still extremely light for those golfers), or Taylor Made is so he||-bent on distance that they've lost their senses completely.

In my honest and somewhat reliable opinion, throw any idea of ReAx 55 shafts out of your head unless your 5-iron swing speed is under 40 MPH and your tempo and transition are slow and soft.

If you want graphite shafts in your irons for the specific purpose of shedding the extra weight of steel and gaining a couple MPH of clubhead speed, look at shafts in the 85 to 95 gram range (I believe there is a newer UST ProForceV2 95 iron shaft). Standard weight steel shafts are around 130 grams in full length. Superlight steel models are in the 110 gram area. Pay close attention to the bend point and torque ratings and try to learn how those attributes will affect the way the shafts play for your swing.