Originally Posted by
thumpism
Rifled steerer would be SPX, wouldn't it?
SLX, SPX, SL, and SP all had rifled steering tubes. Need to examine tubes at the BB for rifling to rule in either SLX or SPX.
I also believe that some Japanese tubing used helical reinforcements on some steering tubes, but perhaps fewer, or more and slightly wider and flatter, IIRC.