Abstract: A system for measuring suspension sag in a vehicle, such as a motorcycle, is disclosed. The system includes a measuring device that attaches to a wheel hub, axle, or other component. The system includes a clamp that attaches to a fender or other vehicle component. The device is connected to the clamp by a cord, which extends from and retracts into the device. When a load is placed on the vehicle, the fender may move closer to the hub or axle. Any slack in the cord may be taken up by a spool shaft in the device. A rotary encoder may measure the rotation of the spool shaft, and the measuring device may calculate a change in a linear distance between, for example, the fender and the axle based on the rotation of the spool shaft.