Need suggestions on crank arm length for the wife. My wife currently rides an Orbea Mitis Dama (52.7 ETT) and has FSA 170/50/34 Compact Cranks. She likes the gearing of the compact for the climbs here in Colorado but has commented that she feels like she spins too fast on flats. She is 5'5", has a short torso, long legs (longer than mine and I am 5'10.5" but I am all torso) and avg arms. Do you think she would be better off with a 172.5 compact as opposed to her current 170 compacts? Her femur is definitely longer than mine and I like the 172.5 over the 175s that are on my MTBs. TIA!!!