Didn't it mention something about 120 degrees being ok as well? I thought I remembered reading between 120-135 is good for you. I'm with KBear though, when I ride on long car rides (well actually all the time now) I keep my seat straight up and even though it hurts it hurts the least. Before the surgery keeping the seat straight up and not being too far away from the steering wheel was the best thing for minimizing back pain during car rides.