Originally Posted by
3alarmer
...I once drove all the way to Merced and back to look at a 58cm Paramount that turned out to be a 21" frame, even after I asked the guy to measure it. So I always ask the current owner, and then I don't count on getting correct information. I want to measure the top tube length and the stem to saddle distance as currently configured anyway, so while I can sort of get a feeling from a photo, I don't count on my feeling being correct either.
The tip is to bring along a tape measure.
If the camera position is good, you can take a ruler or caliper and scale the TT length against the wheel diameter, and come up pretty close to an in-person measurement. Of course it's possible to mess up an in-person measurement as well.