Speedometer error in motorcycles is a serious problem and beyond simple gearing changes and/or rear tire size changes, the factory’s inaccuracy is unfairly increasing mileage readings on vehicles, ultimately hurting values. There are a number of reasons why speedo error in motorcycles exists. FACTORY INACCURACY. Stock speedometer calibration in motorcycles direct from the manufacturer can read 2-10% fast. GEAR, SPROCKET, TRANSMISSION CHANGES. Gearing changes can trigger inaccurate speedometer readings. Changing sprockets can bring on added speedometer error. Changing transmissions affect speedometers, then requiring recalibration. WHEEL AND TIRE CHANGES. Wheel size, wheel diameter and/or tire size changes can alter speedometer calibration. An easy way to fix incorrect motorcycle speedometer calibration is with Speedo Tuner®. Speedo Tuner® is small instrument used to recalibrate speedometer error in most motorcycles. Everyone deserves an accurate speedometer to prevent breaking the law and hurting the value of their motorcycles. Until now the only solution was limited to a few products that require complicated mathematic formulas to calculate an adjustment to offset a gearing or tire/wheel change, but it still carried the original factory offset along with it.