Bicycle sizing for my girlfriend..

[VeloVT]

It's hard to say. Depends on the bike, the setup, and her proportions. You can get a rough idea of whether her torso is much shorter than yours or not by comparing inseams. If her inseam is much longer than yours, she probably needs a smaller frame. (Because her torso is relatively smaller for the same height).

As to bike frame size --
I'm 5'6".

I have a 52cm Bianchi Axis that fits me perfectly. It has a 53.9 cm virtual top tube. I'm running a 90mm stem with a substantial positive rise, maybe 10 degrees.

I also have a 49cm Scott Contessa CR1 pro that fits me beautifully. It has a 51.5 cm virtual top tube. I'm running a 120mm -6 degree stem on it.

The Scott is a much more aggressive position with much more saddle-bar drop, but both bikes fit me well and they are very different frame sizes and setups.

So it's just hard to say . But it's worth a try. It seems at least plausible that your bikes could fit her.

[BleeckerSt_Girl]

I'm 5'5". I have a 54cm Rivendell which is 'about' the right size, though I could probably be comfy on their 52cm as well (never tried one though).
No one needs more than a 1/2" of standover, technically speaking. That's about what I have on my Riv.
You ought to measure and compare your two heights from floor to pubic bone however- that's more accurate and will tell you more than overall body height.
Here's how:
http://www.rivbike.com/article/bike_..._to_measure_it

[Pedal Wench]

No one needs more than a 1/2" of standover, technically speaking.

Even on a cross bike?

[BleeckerSt_Girl]

Even on a cross bike?

What i mean is, lots of people get nervous when they have less than one or two inches of clearance- but you can get as close as 1/2" standover clearance and still be just fine. I'm talking bikes in general, not cross bike geometry specifically.

[1150A]

Even on a cross bike?

I think that's what makes her uncomfortable the most.. There's not much room down there.

Though, I was concerned about that myself at first, I can probably lift up my front wheel about an inch when standing over it. It was kind of scary knowing how close it was at first, but it's not really a problem.. yet.

[1150A]

Unfortunately, the Surly has a 54cm TT..

[VeloVT]

It might be OK. As I said, my Axis (which is a CX bike) has a 53.9 tt -- I don't think that 0.1 cm would make that much difference . What kind of stem do you have on it?

[1150A]

It might be OK. As I said, my Axis (which is a CX bike) has a 53.9 tt -- I don't think that 0.1 cm would make that much difference . What kind of stem do you have on it?

A 120 at the moment.. I'll put the 90 from my current bike onto that one to see how she likes it.

[Cataboo]

I think you want a bit more than half an inch for a cross bike and definitely more for a mountain bike.

Hower, road bikes I think standover height is somewhat overrated - as long as I don't feel like I'm racking myself, I'm fine with whatever on road bikes.

[Biciclista]

the bike feels too big for her. The top tube is 54cm. That might just be too long for her reach!
what's wrong with the smaller bike you bought her?

[1150A]

the bike feels too big for her. The top tube is 54cm. That might just be too long for her reach!
what's wrong with the smaller bike you bought her?

It has track ends and not enough clearance to run knobby tires.

[ilima]

I'm 5'4.5" and normally proportioned, although I have long arms.

My road (Merlin Atreus) and cross (LeMond Poprad) bikes are both 49cm, with ca. 52cm TT and I use short (80 and 90 mm) stems and short-reach handlebars.

My sister is a tad taller and rides and Airborne 54cm, which I don't get, but she likes.

[uforgot]

Unfortunately, the Surly has a 54cm TT..

Yup! The Surly Cross Check sizing is mis-leading. I have a 46cm Cross Check and it is larger than my 53cm Burly was. Has 52.8cm top tube which is perfect for me, and your effective top tube is actually 54.7. I also have about a 31.5" inseam which is somewhat long for my height, 5'5" on a good day. Mine has a 29.6" standover whereas your 52cm has a 30.6". Not sure I'd like it that close.

[roguedog]

use this: http://www.competitivecyclist.com/za...LCULATOR_INTRO

it'll get ya into a decent ball park and then you'll know how you might play around with stems and what not to get the fit in the ball park or.. if it jsut outright might not be a good fit.

though this is more road oriented fit. i dunno if cross might have a slightly different fit since typically the bb are higher than road bikes.

again, this'll probably get you in the ball park and reduce your guessing range ..?

anyway, it'll be fun and interesting. did this with a friend.. and we had lots of laughs and "argued" over the measurements, requiring 2 or 3 measurements. i measured myself and then had an lbs fit and it put me in the general ballpark. your results may differ.. depending on who wins the argument