So then get the RK30. It's the TT30 with a urethane back. If Flux is able to sell you a pair of DS45 urethane backs, I'm almost positive they'll slip right into the Feedback base.
17 Jones Storm Chaser . 17 Never Summer Proto Type Two . 16 Never Summer Swift . 16 Rome Pow Division ST x Snurfer . 16 Gnu Swallow Tail Carver . 15 NS Snowtrooper BIA . 15 Jones Hovercraft
17 Burton Malavita Wing . 16 Burton Genesis X
16 Flow Talon . 16 Flow Hylite