I went with 35mm Kojaks, inflated to 60psi, on all my wheels today. After last Saturday's Cool Breeze ride on some roached out roads my piriformis muscle needs a break. It seems I may be one of the few (16%) who have the sciatic nerve running through the piriformis muscle. Anytime my piriformis muscle gets sore (which happens more often since my hip replacements) it tends to impact my sciatic nerve if I stand to long (piriformis syndrome). Pedaling hard over rough roads can cause a "whiplash" like effect on my piriformis. Getting old is so much fun.
There were a few really rough spots I took to fast while pedaling at the Cool Breeze. Once my foot unclipped out of the pedal. Luckily nothing happened. I have since tighten the tension on my Shimano PD-6800s.
The Schwalbe Kojaks are a great tire. I promised myself a while ago that I would use the Kojaks on rough roads or roads I'm not familiar with. I broke my promise last Saturday. I stayed with the Schwalbe Ones and now I'm paying the price.
I consider the 35mm Kojaks a fast luxury tire. The loss in speed is generally no more then 10% but the gain in comfort is substantial.
Go here for my "Kojak Rear Wheelset" post from April 2015.