20" Frame vs. 18"

[mjhyer]

I am considering purchasing a 29" wheel bike with an 18" frame. I originally wanted a 20" but that may not work out. If I settle for the 18" what am I compromising on? What might I be losing? I am a male and stand 5'9" tall. Thank you for your thoughts and observations.

[rciracing]

I am considering purchasing a 29" wheel bike with an 18" frame. I originally wanted a 20" but that may not work out. If I settle for the 18" what am I compromising on? What might I be losing? I am a male and stand 5'9" tall. Thank you for your thoughts and observations.

I would hope that no shop would sell you a 20" at your height. I'm 5'8 and ride a 16" and thats what I would recommend at your height. You "usually" go smaller w/ 29ers.

[CRAIG2]

I would hope that no shop would sell you a 20" at your height.

As a general rule, I would agree - however, with bikes, I would encourage not making decisions based simply on 'general rules'. Geometries today seem to vary quite significantly. Your best bet is to ride both and go with what fits - the little stickers on the seat tubes are not the be all end all.

For instance, at 6' 4", both my 60cm Trek cross bike and 63cm Trek road bike both fit beautifully. Those are the same mfg - I'd look at someone like an idiot if they said, "You're ____ tall; you need to be riding an ____ size bike."

[rciracing]

Yeah definitely try out different sizes (16 & 18 and look for a 17). What brand(s) are you looking at?

[mjhyer]

I am looking at a Diamondback Overdrive 29