Originally Posted by wagathon
You'd think the next size up would be a 59. It is for some makes of bikes but maybe Sirrus does not have that size. If not, my guess is their 61 is not measured c-to-c, in which case, it's not all that big--definitely not for giants. Looking at some other bikes, for example, a 61 Bianchi or Trek is no bigger than a 59 Lemond wheras a 63 Bianchi or Trek is equal to a 61 Lemond.
P.S., I just checked out the geometry on Specialized's website and they sure make it hard to know what's going on there. They're not giving you what the measurement would be assuming the top bar was horizontal. Even so, the headtube lengths on your brand does seem big, e.g., about 40 mm longer for your 58 than for my 61c Lemond and 63c Trek. It must be a bike that is made for more upright riding. Even your wheelbase is longer (y just a little) so I'd you probably do have the right size frame. If you feel too scrunched, maybe you just need a longer stem.
Thanks! I guess my only gripe is that the saddle needs to be slid all the way back in its track in order for my knee to be properly positioned over the pedal at 3:00 o'clock. The seat tube is definately not 57cm (more like 51cm) but I think they measure it as though the top tube were horizontal. It's a hybrid bike, so it has a little bit of an upright riding position, but it's less upright than I'm used to on my old mountain bike.