So according to Sram website…
Descendant Eagle that I have is compatible with
BB30/PF30-68/73mm, GXP/PF GXP 68/73mm
And the GPX ones are compatible with
BB30/PF30-68/73mm, GXP 100mm/PF GXP 121mm, GXP/PF GXP 68/73mm
But according to Trek my BB is PF92 BB89/91.5 which does not match either of the above including what I already have 9 on the bike. So confused!!