I am 5' 6" (66 inches/ 168cm) I weigh slightly north of 140lbs / 64kg. I am a size small in race cut bibs...Assos, Primal, Endurance, Rapha, Pearl Izumi, all size small.
These are much smaller. They are tight enough that when you take them off, they still feel like they are on. The straps are also TIGHT...