never had this problem but I did put some grip on the shifters of my cyclo-cross bike because in the winter with thick gloves and ice and cold etc. I found my fingers slipped off the shifter and with numb fingers I couldn't feel them properly either. I used skateboard grip tape, cut a few little bits out to shape and stuck it where needed. Works a treat even though it's not that pretty. I used black 'cause that's what I had, you can get it in clear and other colours also.