Switching frames doesn't mean you have to switch posts! Use your old posts without worry with Problem Solvers' wide variety of seatpost shims.
Specifications:
100mm long (including 3mm lip)
3mm lip
Alloy
Problem Solvers seatpost shims are not intended for use with carbon seatposts
Specifications:
100mm long (including 3mm lip)
3mm lip
Alloy
Problem Solvers seatpost shims are not intended for use with carbon seatposts