Some tall bikes have really steep seat stays making it impossible to mount most racks nicely. I just replaced my month old Velo Orange steel rack (you can have it for 55 bucks shipped) with a Tubus Cosmo with room to spare.
I debated over this one or the Nitto but after some photoshopping I decided the Nitto might not fit either.
Highly recconended for tall frames without the extra chainsray length your Riv may or may not provide.
- Ryan