TerraCycle designed this flagpole mount to go almost anywhere. It is designed to attach to any tube from 1/2 inch (12mm) to 1-1/4 inch (31.8mm). It can also be attached directly to a flattish surface like a carbon fiber seat or the side of a cargo box. In that case, the Cateye clamps are not required.
The angle adjustment lets you get a good flagpole angle on any tube from horizontal up to about 70 degrees. Twin adjuster slots let you dial in the perfect flag angle. You can use it on chainstays, seatstays, racks, backs of seats, trailers, all kinds of places. The flag mount itself is attached using a pair of Cateye brand clamps. Cateye clamps are super strong and available in sizes. TerraCycle modifies the Cateye clamps by adding a black anodized bushing to make a firm surface just past the edge of the tube for the mount to press against.
What makes this TerraCycle flagpole mount unique is the adjustable rubber gripper ring that you can set anywhere from "easy in and out" to "absolutely can't even pull it out"! The gripper is a neoprene ring that grips the pole when you slide it in. Since it's rubber, it holds on through bumps and potholes and even a good tree whacking. The low setting gives a nice grip, but you can still push the flag in and pull it out. The strength goes up from there. Insert and remove the flagpole and see how it feels. Insertion will be easier if there is a slight bevel on the end of the pole. Twisting the pole as you insert it makes it easier as well. If you want more grip, tighten the bolt. When it's all the way tight, the stainless washer will clamp directly to the pole, really gripping it.
Machined from a solid block of aluminum 6061 T6, the flagpole mount is super strong. Mounts are made in two sizes, 6mm and 1/4 inch, to fit basically any bike flag pole.
We recommend the flagpole be mounted near the back of the seat and at a slight rearward angle (not quite vertical). This brings the flag further forward, so it's more visible when you enter intersections. It also ensures the flag doesn't hang back too far, making it easier to park and walk around. Depending on the angle of the tube you're attaching to, the Cateye clamps can either face the same or opposite sides. At low angles, the open (bolt) sides can both be up or both be down. At steeper angles, one clamp may need to have it's open (bolt) side on the top of the tube, and the other clamp on the bottom side of the tube. The flag mount is designed to work either way, with the orientation of the clamps extending the angle range. Once you've determined the best arrangement of the clamps, insert the bolts and start them into the clamps. Fine tune the angle of the clamp, then tighten the clamp bolts.