Originally Posted by
digibud
At 5' 11", for somebody to be on a 18" frame (46cm), they would have to use a freakishly long stem. They could not have long legs or the seatpost would not go high enough. I'm 6' and a 56cm frame will typically just barely allow me to ride it if I raise the seatpost right to the max. A 56cm frame is a pretty good size for most people around 5' 11". To ride a 46cm frame....well...I say no. No way is somebody 5' 11" riding a 18" frame. Pictures and video or it didn't happen
. And if it did....BLOW MY MIND (said like Kramer).
You don't need to know the inseam to know that a 46cm bike would only allow the seat post to be raised enough to accomodate a 5' 11" person -ONLY IF THEY HAD SHORT LEGS. My wife is 5' 7" and rides a 50 or 52cm bike (I forget which). For somebody 5' 11" to ride a 46cm bike....they would HAVE to have short legs, or they might sit way down low, I guess. Put a stingray seat on it
. Then their long torso would require a crazy long stem. So I just don't see it and think the OP simply must be somehow mistaken. Perhaps the bike is not 18". Maybe he's not 5' 11". lol
The only thing you need to be careful of is the way different bike manufacturers/marketers measure their bikes. This especially applies to bikes with sloping top tubes that result in a shorter seat tube (so-called compact frames). Some measure to the notional horizontal TT position, some measure to the top of the seat tube.
I have to laugh about the inseam comments -- I am 5'11" and Machka is 5'5" yet we have almost identical inseams.