RP10128 wrote in news:Xns96A0D45BAB0C5richardpu2aolcom@
216.196.97.131:
I need a bike with a top tube of about 50.5 cm. To get a top tube of
that length, I need to get a frame that is one or two sizes too small.
That is, I would have to get a 49 cm. frame, whereas my inseam would
indicate a 52 cm. frame. My LBS says that it doesn't matter that the
frame is so small, but this strikes me as being counter-intuitive.

Top tube is more important, but if your seattube is too small then (depending
on frame geometry), your head tube may be very low. If you want your
handlebars several inches below saddle height, that may not be a problem. If
you want a more upright riding position, then you may have fit or handling
issues.