i'm 5'11", have read frequently that guys my height typically fit a 57cm in most brands, kilo's run large and to size down. went with the 55cm. now if i'm sitting ass flat on the saddle and my feet only my toes can reach the ground, is that a sign that i should've went another size down? also is there anyway to check that the bike i was sent isn't bigger than advertised on the box? i ride it fine but it's hard to stop and get going and i've banged the sides of my inner knees against the frames a few times that's leaving them pretty sore after a straight 7 mile ride.