If you are talking Kona- Then their 17" will not be the same as other manufacturers 17". Not only Kona but a lot of Manufacturers will measure differently. The only way to check out is to sit on and possible Test ride.

I have just bought a new bike and it was a Giant.. They seem to follow a "standard" sizing, but this was a road bike--- Ok -I have a 15" Bianchi mountain bike. Small bike and I am not that small at 5'6" but this bike suits me and my body. Had to change a few things before purchase like seat stem to accomodate me on a small frame and later had to change to riser bars. Yet I can easily ride a 17" specialised, a 17 or 18" Kona and a 19" Giant. They would not be as well set up as my Bianchi but I could ride them without any discomfort.

Back to the Giant Road bike. Started at the shop on a 44cm frame and not too bad- tried a 46 and I was stretching too far. Tried the 42 and what a difference- this one was like a glove except too low to the ground. Raised the seat post and there was sufficient length to get it perfect. Bars were just a bit low so flipped the stem to raise the bars an inch or so and I was there. I know that I will have to change afew things still on it to get it perfect- But without that going to the shop and Trying the different sizes- I could not have said I want this size with these modifications.

Remember I am not that short But I do ride bikes that apparantly are too small for me. You can always "Enlarge" a bike But trying to shrink one is Impossible.