Originally Posted by LowCel
It depends more on the frame manufacturer than anything. All (or most anyway) companies measure their frames differently. Personally I always go by the top tube length, I don't even pay attention to what the "claimed" size is.
With that said I'm 5' 10.5" and I ride an 18" frame.
No they dont. All frame sizes are mesured from the central bottem bracket, through the seat tube to the top of the seat tube. Thats where they get the 17" 19" 21" etc.
If anything, you should buy the bike on the HEIGHT of the bike (hence the frame size). Length that be easily adjusted, (longer/shorter stem, flat bars vs riser bars, dropping the stem a few spacers down on the steerer tube, sliding the seat back, buying one of thos FSA seat posts that are titled back alot more).
You CAN'T change the heigh of a bike. Sure you can change seat height to fit your pedaling style, but that dosn't change the bike height.
So you
should be buying the bike on clearence from the top tube. If you dont have enough clearence then you should buy the smaller size. Of course it depends on what riding you are doing as to how much clearence you feel you need, but it comes down to personal preference.
