i'm 5'10" and i ride a 52 and it fits great. one of the things you should know about the bareknuckle is that the seat tube is sized center-to-center, so my 52cm is more like 53.5 center to top of seat tube measurement. the 52 also has a 54.5cm top tube, which is why i think many people find the frames to run large for their size. going by the seat tube measurement alone, you may find yourself stretched out too far on the bars because as the frames get smaller, the top tube lengths tend to be proportionally longer. i would suggest a 48. that would give you a 52cm top tube. compare that to your rush hour and determine whether you feel you need a longer or shorter reach to your bars. the seat tube size is less relevant because your seat post is easier to adjust than a stem/steerer tube length.