Well, I'm in the process of deciding to buy a Ziggurat. I've been riding on large frames most of my life, a large (19") Sugar with Genesis, and currently a large (19.5") Fuel. I wanted to go to a smaller (17.5") frame for more agility since I plan on seriously racing the Ziggurat. By going with a smaller frame and thus shorter top tube, am I negating the purpose of Geneiss Geometry? I'm about 6 feet. I have test ridden both a medium Ziggurat and large HKEK cuz they didnt have a large Ziggurat. A little bit more laid out on the HKEK as expected. And they both feel good in the parking lot, too bad I can;t take them on the trails. Suggestions/comments? Thanks.