Hi guys, might be a bit boring, but once again I'm coming back from a long while off and keep getting random queries enter my head while I'm at work. One of these is just how much the geometry of frames has changed over the past few years. For sampling sake I'm going to compare the 2003 Echo ES4 that I ride at the moment and the '07 Gu that I am likely to buy in the future, then ask you guys whats brought about these changes. The Echo has a zero drop bb, 15" chainstays, a 72.5 degree headangle and a wheelbase of around about 1040 whereas the GU has a 60mm rise on the BB, a 71 degree headangle and a wheelbase of 1080. To me, that sounds like an old Koxx Levelboss with slightly shorter stays and more standover height. Except for one thing: why has the BB rise come about? I know that on average the new bikes aren't as drastic as the GU, but all have a rise of some sort. Is it just clearance or does it help in other ways too? Cheers. J