Originally Posted by
foldup68
Looking to buy a 70,s twenty or stowaway and I want to upgrade the gears new seat handlebars to bring it up to date. but still keep the old look. anyone have any ideas what type of gearing to put on there i was thinking about making her a 18 speed as it will be for touring.
Thanks folks. help much appreciated.
I have converted many 20's to a 73mm bottom bracket and 24 tpi threads and have had no reported issues and have been riding my own P20 for well over 5 years with a 73mm cartridge bb... the Phillip's has a stock 72- 73mm bottom bracket so no facing was required but the threads needed to be re-tapped.
The rear spacing is problematic in several ways as the frame is 115mm and will accept a modern IGH with no issues while using a derailleur equipped wheel poses some issues. The frame needs to be cold set and the rear seat stays are rather beefy and will interfere with the chain when it runs on the outermost cog.
Spacing a new hub requires that you add spacers to the drive side to give the chain the room it needs so a 126mm hub needs a 130mm spacing or you can go beyond that and modify the stay so that it offers adequate clearance.
If you are a guy like me and work in a frame shop, you cut out the rear triangle and replace it with a modern one with 130mm spacing, a proper dropout hangar, and cable guides and stops, build a new fork, and powder coat it.
I have chronicled the entire saga here... I run a triple with a 48/52 half step and 40 tooth granny and built up a custom 7 speed freewheel.
Forrest - 1973 Phillip's 20