Abstract: Optical fiber wound onto a take-up reel after production is invariably tensioned such that results of characterization tests performed on the wound fiber are markedly different from such results obtained when the fiber is untensioned. Doubly winding the fiber to minimize tension is a laborious procedure. The invention covers a reel which has an adjustable hub circumference. Adjustment can be made with the fiber wound onto the hub so allowing rapid characterization of the fiber prior to restoring the fiber and the hub to their normal storage positions for fiber shipment.