AND, replacement THUMB SHIFTER sets (
with cables) are typically available for under $20 on eBay (
direct from the "source") ...
- The right hand thumb shifter can be toggled between friction & indexed mode ...
Because thumb shifters can operate in
Friction Mode, future "repair" would be to simply cut a new "friction" washer from a plastic jug ...
OR, if there is truly no interest in shifting with the current shifters, the one can EITHER "lock" the derailleur in place on the preferred Cog OR (
presuming the shifter is viable on a few indents) to simply adjust the shifter to work across the limited-but-desired Cog range.