Bartlett, DeKalb and Jackson Park had several Grass-pavement 90 degree transitions. Mud tends to accumulate right there, and you often still have mud on your tires. I have seen several people just in front of me wipe out on those turns. I ALWAYS take those transitions very easy, simply not worth trying to force it. Crashing on pavement isn't worth the risk. For safety's sake, it would be great if course designers allowed a shallower angle to transition instead of a sharp turn - not hard to incorporate, even just by making the course a bit wider at that point.

At Northbrook there was a transition from that steep off-camber to a hairpin pavement corner that lots of people wiped out on as well. Lots of mud on pavement and tires made it very slippery and many took the corner too hot - not the course designers fault.

AS MJH2 said, road brakes would have worked on every course - except for the Tour de Groundhog in Springfield where even a derailleur was a disadvantage.