You need to change the wheel size in your speedo set up .Masure the wheel diameter (in inches or millimetres)You do this by marking tyre and floor with chalk and push bike one wheel revolution ,make another mark and then measure distance between both marks .This is the measurement you need to put into your speedo setting for wheel diameter .You need to enter the setup on your speedo ,scroll thru to wheel diameter and enter new info .Good luck
