They are made to handle traditional bow weights between 50 and 80. I shot them out of bows between 50 and 74 pounds with no problems. Sorry, but I do not have the deflection numbers.
The Continuous Taper Technology also gives the GrizzlyStik a tremendously wide spine range. GrizzlyStik Alaskan is designed for 50#-80# bows and has a finished arrow weight between 550 and 650 grains.
Hope that helps.