If the seat rails of your saddle are more than 3.5 inches (89mm) apart, you will need the following adapter for the Randonneur® rack, Seatpacker® hanger and Rollpacker® rear hanger. The challenge with some of the classic Brooks saddles such as the B17 and some models from Selle Anatomica is the large width between the seat rails. We’ve solved this with an adaptor that is much wider at the quick release point, where it attaches to the seat rails. The adaptor can be positioned vertically along the upper back part of the seat rails, or horizontally and closer to the seat post for when riders want to position the saddle further back (in the direction of the rear wheel.). This adaptor is not compatible with saddles equipped with coil springs.