Same here... There is something about riding a road bike and stretching out. I went out yesterday for a nice 20 mile ride and was perfectly fine. It felt great!

Regarding lower back pain at L5/S1 and that sciatic tingly sensation... I might not be able to blast a golf ball 275 yards off the tee anymore (right now, if I tried a full powered swing with my driver - I'd be in traction! ), and I might not be able to run a 10K, but eventually I will. For now, I focus on riding my old Fuji and increasing my speed and endurance.