Hi Quinten,
You caught some good action for sure, but it seems that every shot you posted was back-focused. Take a look at the fans and the non-riders in each shot - see how they are sharper and more in focus than the subject? I don't know if this is because your technique needs some work to follow the action better, or if it's because the 85 f/1.8 is a screw drive lens and isn't great for keeping focus during fast action. I have the 85 f/1.8 and I used it once in a basketball game and that's all it took for me to discover that it just doesn't consistently adjust focus fast enough.
I recently attended the North Texas State Fair in Denton and had a chance to go see the rodeo. I have a whole gallery, but here's one photo where you can see the rider is in focus but the signs in the background are nice and blurry:
Granted, my equipment is a little different than yours - I used a D700 with the 70-200 f/2.8 VR lens, which is a great combo and the lens focuses super-fast. I'm glad you had a great time - we had a fun time as well. Just work on your technique of keeping the focus point on the subject and you may get more keepers in the future.