Sag Master
Voted as one of Dirt Bike Magazines 25 Best Tools Ever Invented, the Sag Master is a tool that makes measuring Static "Race" Sag a snap because you read it directly.
The concept is simple. There is a "nub" on the back of this tape measure (yes, it works as a tape measure too!) that gets inserted into the hollow axle. Then the tape is extended to a vertical reference point on the frame and "locked in". When the rider is put on the bike and the Sag Master nub is reinserted into the axle the "sag" is measured directly.