We have two single lane roundabouts on one of our routes (Dove Road in Southlake, TX.. lots of cyclists). We haven't had any issues, we just follow common car rules.. yield to enter, and take the lane, signal our exit, and all is good! I take it solo a lot, and haven't had any issues.
There are three double-lane roundabout on the NE shore of Grapevine Lake that are nightmares. 98% of traffic basically continues the same direction on the same road (the crossing roads see little traffic), and cars seem to travel 50mph on that 35mph road, so cars stopped using the roundabout lanes, and they just take the straightest path across the circle, which cuts the lanes. If someone actually tried to stay in the lanes, they'd get hit by the cutters!
