Originally Posted by
mstateglfr
I've been meaning to ask this about other member's upper tier late 80s schwinn road bikes, but keep forgetting.
I have an 87 prelude and an 88 premis, both tenax, and the seat tube is quite literally slammed and squished into the bottom bracket shell to fit with the down tube(vs being mitered/coped to fit inside the shell with joining tubes).
Any chance you happened to look at the joining method of your Prologue? I know the Prologue is Panasonic built with Prestige tubing, vs Greenville built with Tenax tubing like the rest of the upper tier of bikes, but just curious if the slam and squish build method was used for the highest level bikes too(with Prestige or SL tubing).
When I converted my '88 Premis the tubes were "slammed and squished" as you put it, although I'd say they were squeezed at the end to make them clear the other tubes in the bottom bracket. While this worked ok for old school BB's when putting in a modern Shimano 24mm bearing set I did have to take a Dremel tool to the tube ends so they wouldn't interfere with the threads of the bearing cups. However, my '88 Circuit (Columbus SL) has nicely mitered and fitted tubes in the BB area. I've also modernized an '87 Super Sport which is also Tenax but the tubes are also mitered not squished. So it seems to me that only the higher level bikes, Super Sport, Circuit, Prologue, Peloton got mitering and the lower ones, Tempo, Premis, Prelude, got squished.