The five helical ridges in SLX. and SPX provide additional stiffness with only a nominal increase in weight. The concept had originally been used on the Columbus steerer tube. When Campagnolo's brazed-on front derailleur hanger appeared circa 1982, there was a rash of failures. The helical ridges were applied to the seat tube to add more material for brazing. Pro riders noticed a slight increase in bottom bracket stiffness and the concept was added to the bottom bracket ends of the down tube and chainstays to produce the SLX and SPX tubesets. TSX expanded on the concept by running the ridges the full length of the top and down tubes and reducing the butts to 0.8mm.