I have tried both of them. Bicycles can reduce thighs, but the slimming effect is limited. The weight loss effect of treadmill is hard to say. Aerobic brisk walking or jogging for about 40 minutes is good. But considering that many people will get bored and give up, this is not very impressive. It is suggested to practice "Insanity", which has a good effect and does not need equipment. Many people, including me, have practiced for 40 minutes every day for a month, and only once or twice can they say that they have done their best, and only 1 time can reach the standard of 90%. But even so, I lost 6 pounds a month.