mountainwalker

Of course we'll try some on at a nearby shop, but to narrow things down, which frame size do you suggest for a woman 5 ft 6 in. tall, with slightly shorter legs and longer torso (30 in. inseam), and would you suggest a man's frame given that men typically have proportionately shorter legs than most women? Really appreciate your suggestions. She'll be riding either a road bike with flat bars and slightly more upright posture than typical road, or a hybrid, both with 700c wheels. Here are her complete measurements from the Competitive Cyclist bike fit measurements:

Actual measurements:
Actual Inseam30 In
Trunk24.5 In
Forearm12 In
Arm23.25 In
Thigh21.75 In
Lower Leg19.875 In
Sternal Notch53 In
Total Height66 In

Competitive Cyclist Fit Suggestion For Road Bikes:
Fit Style
The Eddy Fit
Top Tube Length51.5 - 51.9 Cm
TOP TUBE LENGTH

This measurement is along the top tube, from the midpoint at the seat tube to the midpoint at the head tube. No single piece of frame geometry has a greater impact on comfort than your top tube. If you plan on paying attention to one measurement and one measurement only, make it this one. Keep in mind that we do not measure the actual top tube on bikes with compact frame geometry. Rather, we use an "Effective Top Tube" measurement - an imaginary line drawn parallel to the ground along the length of the top tube.
Seat Tube Range CC50.5 - 51 Cm
Seat Tube Range CT52.1 - 52.6 Cm
Stem Length9.1 - 9.7 Cm
BB Saddle Position67.1 - 69.1 Cm
Saddle Handlebar48.8 - 49.4 Cm
Saddle Setback3.7 - 4.1 Cm
Seatpost TypeNot Setback


Competitive Cyclist Fit Suggestions For Mountain Bikes:
Fit Style
The XC Fit
Standover Height Range28.6 - 29.2 Inches
Virtual Top Tube Length22.3 - 22.7 Inches
VIRTUAL TOP TUBE LENGTH
This is not a measurement of the actual top tube itself. Rather, this corresponds to the mountain bike industry standard of measuring an imaginary line drawn parallel to the ground along the length of the top tube from the midpoint at the seat tube to the midpoint at the head tube. This is also known as an "effective top tube." No single piece of frame geometry has a greater impact on comfort than your top tube. If you plan on paying attention to one measurement and one measurement only, make it this one.
Stem Length8.7 - 10.3 Cm
BB Saddle Position67.1 - 68.6 Cm
Saddle Handlebar49 - 50.6 Cm

MichaelW

those fit systems assume a racing position.
see here.

mountainwalker

Thanks MichaelW that was a very helpful article. One thing I'm wondering - if she's picking up a fast commuter/fitness bike, essentially a road bike with flat bars and 700c wheels, or, a hybrid with smooth 700c wheels and flat bars, do you follow mountain bike fitting or road bike fitting? The frame shape of these types of bikes is closer to a mountain bike, with a sloping top tube not a straight one, so do you follow mountain fitting or road fitting?

For example, using this general calculator, Mountain Bike Size Sheet | eBicycles.com at 5 ft 6 in. tall and 29.5 inseam, it recommends a 16.5 in. (42cm) frame for a mountain bike, but for a road bike it places her at a 51cm or 20 in. frame. Say we use a Marin San Rafael as an example, with hybrid frame and smooth 700c wheels, would she be better off on a 50-51cm/20 in. frame, or a slightly smaller frame?

I realize she needs to try different bikes, but this is helpful in narrowing things down.

NormanF

I'm a guy just an inch taller than your woman friend. For me, I'm happiest on a 53-54 cm road bike, I'd be comfortable on a 51 cm-52 cm CX to compensate for the higher bottom bracket, on an MTB and hybrid, I ride an 18" and on a 29er or fat bike I ride a Small frame bike.

Sizing may very a bit across branding and depending on the geometry a bike manufacturer lists for its models but in general I find this to be a good fit for someone who is not 6" tall. Good luck in finding the road/hybrid bike for your needs.