I am 5'10 and have about a 31" inseam. After about 1 week of riding, I need to lower the seat down about 1" or so. I am 47 years old without any prior riding experience, except back when I was a young teenager. Most bikes here in China are small frames and when I checked out the Giant bikes, all the had was the very small framed bikes. They said They could get me a bigger framed bike, but it would take a few months to get it. I did lots of research and reading about sizing here and on other forums, and a 20" frame of this model seemed like the best fit.