I know I should be upgrading to 12 or whatever the latest and greatest is but I want a low cost way to eek out some more life on the second bike.

Excuse my lack of knowledge but Will a new Sram 9spd X5 (New) or X7 rear derailleur be comaptible with the 9spd shifters that are on there (labelled 9spd impulse technology and changing a higher end sram derailleur with red alloy body and black box carbon cage..)?

thanks

Yep, it’ll be fine. You have X.0 currently.

thanks!