Originally Posted by
CABELLOJO
So, after researching it seems I have the famous Shimano 10-speed only freehub.
I believe that is the infamous deep spline hub they had for a couple of years. The only cassettes that had deep splines were Ultegra and Dura Ace 10sp. Possibly 105 as well but I'm not sure about that. Good idea in theory but stupid in execution since you're limited in cassette selection. I have an aftermarket wheelset with deep splines and I didn't even know about it when I bought it.