Hello all. I recently bought a Mongoose Dual Suspension Mountian Bike with 7 speed grip shifters. I would like to change them to trigger shifters, but I can't seem to find 7 speed shifters. Can anyone tell me what I can do to change my shifters from Grip to Trigger shifters. I only ride casually to and from school and whatnot, but I cannot shift the grip shifters easliy do to a wrist problem. Please help!