Umm I had an hour long fit on my mountain bike. And I had one guy tell me I was too small to ride a 29er. I asked him if he had heard of Willow Koerber, he said yes, I said I stood next to her and am taller than her but watched her race a 29er. Funny thing is he told my teammate she had the perfect bike for her build, she is 1/2" shorter than me, shorter inseam and has the same bike I do. Did I mention he wants to date her? I am 5'2.5" and ride a 15.5" 29er full suspension, 29" inseam. Best fitting bike ever. I do think guys tend to have misconceptions about what women will fit but people who truly know what is out there and how they fit won't tell you smaller people can't ride 29ers.
But no, my mountain bikes won't cause me pain if the fit is 1/8" off but my road bike did. However having a dialed in fit did alleviate knee and shoulder pain I was having mountain bike because it was off a lot. So yes, they need to be fit.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan