Christine,

One more thing I nearly forgot -- when you measure your inseam, make sure to do it in your cycling shoes as that will increase it and thus make the standover more. So, if you're 26" in bare feet, say, you might be 26.5" in your shoes. I have road shoes with cleats that raise me up even more, which gives me good standover on my 17.5" Terry Isis. Its standover height is stated as 28'2", and my bare feet inseam is just 28. In my bike shoes I have a good 1" of standover space!

Hope this helps!
Emily