I'm running Continental Super Sports 700x25c at 120 psi. I really like how the Klein handles. One thing I read on another thread is that supposedly the old Kleins (mine is pre-trek) are rougher than the new ones. After a long ride, weird parts of my body ache that never hurt otherwise...shoulders, tops of the arms, elbows, even my arm bones seem sore. And I have to wear padded shorts, even though I don't on my other bikes. I have B-17s on all the bikes....oh wait! I don't have one on the Klein....I don't know what's on the Klein. I bought a brooks for it but used it on something else instead.

I should try different tires on the Klein...I just assumed it was the aluminum, having only ridden steel before. Although, I sure like 120 psi....