Originally Posted by
thomson
So, Steve, what is the difference between a 53 and a 58 ? Is it just shorter tubes or would you need a different set of lugs too?
All else being equal, just a lower toptube. It would just slide down the seat and head tubes
5cm from the 58cm position.
But it's likely that the toptube would need to be shorter for the 53. That would require
opening the ST/DT angle a bit to keep the lower headlug at the same elevation.
For really radical geometries you need to either cut and weld existing lugs, fillet braze
or weld the tubes.