Mortop quick-release hub is designed base on human factor concepts, such as safe lock quick remove, lower wind resistance, save labor and comfort, and aesthetics appearance This invention is improve integral screw nut of conventional quick-release hub to include a screw nut with a washer, so as to achieve a spherical locking device with micro adjust- ing function, and the improved screw nut engages with a shaft stably to prevent inner and outer teeth from disengagement, thereby obtaining safety. No matter unlocking or locking the seat clamp, the quick-release grip has an unsharp and smooth outer surface to be rotated at 360-degree, thus operating smoothly and comfortably. Aerodynamic quick-release grip meets with mechanics theorem, is operated with save labor, and includes spherical member fixed on a distal end thereof to prevent fingers from slipping during operation. During locking operation, the curved quick-release grip matches with a front/rear fork to prevent from disengagement during shock, enhancing safety and lowering wind resistance. The Mortop series of quick-release hub is anodized on its aluminum alloy surface to obtain delicate and shining appearance. It is to be noted that this seat clamp provided the customers with various color options to satisfy personal and DIY trend.