We did south kaibab up north kaibab in 14 hours. Going down was easy and we got to the Colorado river in under 3 hours. Poles were helpful. Up north kaibab was long and brutal in the 107 degree weather, swimming in ribbon falls was a lifesaver that kept us from overheating. I constantly soaked my clothes in the river and that was a huge help. But oh man, the most beautiful and amazing hike ever.