In order to determine which saddle clamp you’ll need, you have to measure the outer diameter of the bicycle frame. Use our Pitlock measuring guide to determine which saddle clamp you need. The standard size is 31.8mm, but your seatpost may vary.
A Note about Seatpost Security: If the seatpost doesn’t have a separate clamp, and only has the eyelets welded on the bicycle frame, enough plane pressure surface needs to be available to install the Pitlock closure. Since the eyelets of the bicycle frame cannot be clamped, just as ones of an additional plane saddle clamp, an optimal connection between the two pressure surfaces is not possible.