SL and SP had helical ribbed steerers long before the introduction of SLX. I don't know when ribbing first appeared though.
Mark Bulgier Seattle, Wa USA
Glenn Jordan writes:
> The ribbing is in SLX steerer tubes, introduced after the
> early 70's I think. It added strength to the SL (Super Light ?
> Stupid Light ?) tube sets. Is the any helical ribbing found
> elsewhere on the tubeset ? Earlier Columbus tubesets weren't
> labeled SL or SP or SLX, just "Columbus", like on my 1975/76
> Trek 910. No helical ribbing on this frame, if I remember
> correctly, even though it is Very Large.
>
> A replacement fork ?