Here are some pictures I took of a frame for someone who was asking me “how big” a 24″ bike could be. In the pictures the seat post is at the max. From the center of the bb, to the top of the seat where the sit pads are is 35.5”. The top stem is 17degx110mm with a cut down Titec H-Bar with some rise. The bottom stem is 10degx110mm with an HD H-Bar.

blog_24size1.jpg

From the sit pads to the stem clamp center is 32”.

24 inch sizing

The layback seat post does change things slightly (so does a straight post) but it depends on how you measure things. In the picture the seat post is at the maximum extension. Remember, from the center of the bb, to the top of the seat where the sit pads are is 35.5” – (and consider crank length when comparing this with your inside leg measurement).