Quintessentium

probably looking for a smallest size of 700c bikes, even women's bike is ok.

just looking for toptube is shorter than 500mm,

450mm – 470mm would be perfect, I'm not even sure that could exist.

dsaul

Such a frame would have some serious toe overlap with the front wheel. Also, top tube length is not really a good metric to compare frames. With sloping top tube bikes, the method of measuring top tube length is all over the place between manufacturers. The proper way to compare frames for reach is to use the "reach" measurement, which is the distance between the center of the bottom bracket to the center of the top of the head tube. Most geometry charts now list "stack" and "reach" numbers, as well as the traditional geometry numbers.

mstateglfr 

https://www.jamisbikes.com/usa/renegadeseries.html

Jamis' steel and aluminum frames come in a size 44 that has an effective top tube of 502mm and uses 650b wheels. Really neat feature is that the fork is designed to the frame sizes so that overall trail is relatively similar across sizes.

This size 44 ia advertised for young teens and would be intended for probably 4'10-5'2 or so(guess based on geometry chart).


What you are looking for many only come in a 24" wheel size. For example, here is an old Kona offering...
https://2016.konaworld.com/jake_24.cfm#spectop

5teve

https://salsacycles.com/bikes/vaya/2020_vaya_grx_600

chas58

Agreed, you want a "700c" bike that has been downsized for 650b wheels to keep the same handling (and lack of toe overlap) of the larger frames. The ones above are good options. Canyon Grail does this too. Their specs say 162-166cm height, 516mm top tube (so a little bigger than the bikes above).

tangerineowl

What size 700c max would you want to run?

Quintessentium

as small as I can get.

if you mean, tyre clearance, the bigger the better, but I'm perfectly open to different suggestions too

tangerineowl

1x builds:- https://kidsracing.co.uk/collections...-low-standover

They do up to 54cm, so its more proportions than just kids.

HUP website mentions:- 68mm bb. 1x is 44t max. (can be setup 2x 50/34 max). axle 142 / 100.
Clears a 650b x 42 or 700x38.

44cm mentions a 49cm top tube.
37cm mentions 48cm.
Probably want to contact them to confirm effective top tube lengths / standover on a bike size.

aggiegrads

How did you arrive at this number? If you worked with a fitter, then all should be good. If you are extremely short, have unusual proportions, or have flexibility or adaptive problems, then you may be best served going custom if it is within your budget. I have short legs and a long torso, so I have been difficult to fit; it sounds like you may have the opposite problem. Looking at stack and reach numbers will be very helpful - @dsaul gives good advice there. I would add that effective top tube measurements are more likely to be correct, and I have absolutely shopped/sized frames on ETT - for me, this is a better measurement for a frame. The seat tube is the most adjustable measurement (more adjustability in a seatpost than in stem length) and changes to saddle height have minimal impact on the bike’s handling, where stem length changes are much more noticeable. When someone talks about a bike that is too big or too small, they are rarely talking about the fact that they cannot get the saddle at the right height, but that the bike is too long or too short, and they cannot achieve a comfortable position.

Are you set on 700c? If so, what is driving the decision? This will be the biggest challenge. With 650b/27.5 rims now available, most reputable brands now spec smaller wheels on the frame sizes below ~50cm to avoid the trade-offs inherent in 700c/small frame designs.