I had lumbar back surgery about 5 months ago. I was advised that a road bike is not the best alternative. Bending over may temporarily relieve the pain, but what you are doing is relieving pressure on the back side of the spinal column, but you are transferring that pressure to the front side of the spinal column, so it is actually putting more pressure on the disk, which will cause it to protrude more and eventually herniate. I was advised to ride a hybrid, sit as upright as possible and ride a suspension saddle, to relieve some of the bumps, but also to force you to tighten muscles to stay on the saddle which causes them to improve in strength. Do not use a waist belt because this takes the place of muscle strength which will eventually cause muscles to weaken and increase the problem. FWIW.