Climbduro creator hopes to expand its offerings to riding hubs across North America and beyond They’re popping up on trees, at the beginning of climbs, along mountain bike trails around southern Alberta—small orange signs that say START. Do they indicate the start of your suffering? The start of a challenge? The start of something special? In a way, they’re an indication of all three. These signs mark the beginning of a Climbduro segment—a stretch of trail, asphalt, or gravel that tilts upward and where, depending on your climbing prowess, you may find suffering. You will definitely find a challenge, whether you are challenging yourself or someone else. And best of all,…