One of the better places (I'm sure they're lots) to buy an e-bike is on Xi-Chang Lu. It's loaded with stores......I think some second hand one's as well. We have a Wao Pai 王派, which tops out at 35km. I would definetly reccomend getting something that will go about 50-55....seen a lot of Xite's that'll easily do that. Have to second everyone on the lock and always parking in a safe garage....thiefs are amazingly slick at swiping these things......You can get an excellent U-Lock for 200 RMB-worth every cent-also on Xichang Lu.....coming from yi er yi da jie, take a left at the big bridge past jian she lu......ride up and you'll start seeing all the shops on the left.