Question about conversion kit BBs
Hello all, I'm trying to learn if/how I can use a mid-drive kit to upgrade the 35yo frame of my daily ride.
My frame is threaded BSA on one side of the BB, and Italian on the other.
(The only reason that my younger self was able to afford such a nice frame was that it had been stripped during assembly on one side, and re-tapped larger.)
I know that BB systems went through a number of changes in the intervening decades, splined cranks etc. I have an old-school cup and spindle setup. If it ain't broke...
I have watched a lot of videos of people installing mid-drive kits, but (frustratingly) I cannot tell from any of them if the kit BBs are threaded in like old-school BBs were; or if they are just a compression fit, similar to the old Mavic BBs?
My question is this: does the BB threading of an old frame matter when looking for a kit, or is BB shell width the only important factor?
Thanks kindly