Have you tried riding your bike while not placing all of your upper body weight on your palms thereby cutting the blood curculation to your fingers and also pinching the nerves in your wrists. When you feel tingling in your hands while riding your bike, take notice of your elbow joints. Do you have to release preasure on your hand grips to be able to flex your elbows. Are your feeling discomfort in your elbow joints. If either of the last two comments apply then you are leaning on your bars! Try placing more weight on your butt, try wiggleing your fingers once in a while when riding. If you must lean back to do this, you are leaning on your bars. Take notice of presure being placed in your palms while riding. I you have preasure, you are leaning on your bars. Your arms should be relaxed and so should be your hands when riding. Master this and not only will the tingling become nonexistant, but your riding ability will improve.