My freind had his back operated on a year or more ago. He still has issues with it. My question is, is there a road bike that he could get that would be easier for him on his back to ride. He is very interested in getting into riding and would like to start training to do some longer mile rides. He is 6' 4" and 240 - 250 lbs if that helps with the responses as well. Thanks in advance for any input.