Using the Bontrager Speedtrap sensor on a Trek 7.5 FX requires an additional spacer in the fork this bike uses the Bontrager SSR wheels which leave extra space between the spokes and the sensor. I recently purchased the 7.5 FX, Node 1, and fork mounted Speedtrap. Could not get it to pair and operate. Only one of the guys at the local Trek shop knew about the spacer. From the Bontrager site: "Some wheels may require the use of a SpeedTrap spacer: Part #414162". It should be included with the sensor but is actually about a $3 accessory.