Many modern road and gravel bikes use D-shaped seatposts with flat rear surfaces for aerodynamic advantage. The problem is that most taillight mounting straps expect a round post to wrap around. On a flat-backed post, the strap pulls against the edges rather than conforming to the surface, causing lights to slip or rotate during rides. The Lezyne D-Shape Seatpost Adapter creates a curved mounting interface that gives KTV and Strip Drive rear lights something to grip properly.

The adapter sits between the flat post surface and the light's rubber strap, providing the rounded profile the strap needs to tension correctly. At 4 grams, it adds essentially nothing to the bike while solving a compatibility issue that would otherwise require buying a different light system entirely. The material grips the seatpost without damaging the finish, which matters if you're running a carbon post where scratches can compromise structural integrity over time.

Compatible lights include the Laser Drive Rear, Strip Drive Pro Rear, KTV Pro Smart Rear, KTV Pro Rear, KTV Drive Rear, and their STVZO variants. If you already own one of these lights and recently upgraded to a bike with a D-shaped post, this adapter maintains compatibility rather than forcing you into a new lighting system. The low-profile design keeps the light close to the post rather than cantilevering it outward where vibration becomes more of a factor on rough roads.... Read More