I have a 2008 QU-AX 20" crossfire uni with the red ISIS hub and QU-AX cranks.
im building higher drops that had intended but its addictive.
which should i upgrade first- hub or cranks and what is the difference between the red ISIS and yellow ‘splined’ hub?
the cranks will be the first to bend, you wont have to upgrade your hub for a very very long time. ISIS is super strong and only a few people have bent the hubs but that was from absolutely insane riding.
If you want to get new cranks i would suggest the Kris Holm moments, they are very strong, kind of on the heavy side but good and cheap