Around 1981 Reynolds rebranded their standard 531 DB tubing for marketing purposes. Their standard 531DB tubing was divided into 3 distinct sub groups:
531C = Competition, it was the old 531 DB tubeset
531ST = Super tourist, a heavier version of the classic DB tubeset
531 Designer Select = Designer Select tubesets allowed the builder mix n match 531C and 531ST.
At the same time Reynolds lightweight 531SL was rebranded into 531P or 531 Professional.
531P = 531 Professional which is the same tubeset as 531SL
Last edited by miamijim; 06-20-09 at 03:26 PM.