Funny. I actually have a suspicion for a lot of us a mullet bike is going to be faster going up. Its something I will likely test for the youtubes in an XC/Trail/"backcountry" application. Here is the hypothesis... *A lighter wheel goes uphill faster than a heavier wheel with the same power applied *All things equal (tire, rim, etc) - a 27.5" wheel is lighter than a 29" wheel. *The benefits of a 29" wheel (for most mortals) are not applicable in most climbing situations on a MTB (Inertia is higher at speed, rolls over chunk better) Before anyone says...