5' 1 3/4" w/26" standover, the builders for my custom Rodriguez reccomended 170m cranks for me. Besides taking the standard standover measurement, the LBS guys took another measurement with me kneeling to get my femur-to-tibia ratio. Turns out my femurs are way longer than my tibia. Who knew? I think shoe size went into consideration too. My knees are definitely happier now than when I had 165m cranks. Just so you know my current bike's geometry is way different than the bike I had with the 165m cranks on them, so that may make a difference too.