Originally Posted by
wunderchicken
Thanks - that PDF is very helpful. My understanding is the hole in my frame is complaint with the BB386 Evo spec and Specialized or the bike shop pressed PF30 cups into said hole? The exterior facing side of the PF30 cups are the threaded part then?
If your frame is threaded (per your LBS, and from what I can gather most all Sequoias use threaded BB shells), the cups
are not pressed in. Rather the cups thread in but the bearings themselves are outside the BB-shell. Remember the crank axle is itself 30mm, inside a standard 68mm roadie bottom bracket the internal bore is only 34mm...that PDF? Remember the bearings themselves are 46mm, there's no physical way to press them inside the frame as they're larger in diameter than the shell, so they are outboard in cups that thread in. What is more the bearings are supposed to be 86.5mm apart per the standard and a 68mm BB shell is only 68mm (hence the name).
What you're getting confused by, I think...is the interchangeability of the bearing cartridges themselves, as well as the interoperability of the cranks. Both PF30 and BB386EVO use the same size of bearing cartridges (46mmx30mmx7mm)--but PF30 press-fits them inside a 68mm shell...BB386EVO however is a swiss-army knife, the bearings can either be pressed in or reside in threaded cups outside spaced at 86.5mm (and with spacers the 386EVO cranks can be made to work with narrower BB30/PF30 systems)
https://www.mantel.com/blog/en/botto...-brackets/#BSA
The cups are outboard of the shell, by themselves should itself looks like this by itself:
https://www.maplegrovecycling.com/pr...t-243422-1.htm
Here's what a BB386EVO SLK crank looks like installed in a threaded shell...you can even just see the wavy-washer for bearing preload in this photo of my gravel rig: