I ride a Trek Pilot 5.2 WSD, 2007. It is a split (cutout) saddle. The LBS told me the saddle design was stolen from the Terry Butterfly, that it is the Trek Bontrager version of the Terry Butterfly. I haven't had any problems on it, no sore rear or even a starting glimmer of any discomfort, but I haven't ridden it over 30 miles yet either. My hunch is I won't get a problem. I like the saddle.