Originally Posted by
Lazyass
Does anyone have a good guess what size this Miyata is? '83 or '84 Ridge Runner. I have a hard time determining what will fit me on non-compact geometry MTB's. The seller says it's a 18 inch medium. If it is, 18 inches would be fine it it were a compact frame. The smallest road frame I can ride is 54cm. I can see the TT length is fine but on this bike I wouldn't want a foot of seatpost sticking up.
it looks like this pic is taken pretty close to dead on, perpendicular to the bike. the rear rim measures about 314 pixels, and the top tube measures just under 300 pixels. 26 inch rims measure about 58cm, so its definitely less than 58 top tube. math puts it at about a 55.5cm top tube.
obviously an extremely imprecise way of measuring, but maybe better than guessing