Flange U.Nut 12mm

This aftermarket flange nut is manufactured for the SYM Jet X 125I 125cc, compatible with 2021-2022 model years and cross-referenced to OEM number 90306-X11-000. The flange nut combines the functions of a standard hex nut and integrated washer into a single component, providing improved joint reliability and faster assembly in high-vibration environments.

The M12 flange nut features an integrated washer face that distributes clamping load across a wider bearing area than a standard nut of the same thread size. The flange diameter of approximately 24mm provides a bearing area of 450mm², compared to just 95mm² for a standard M12 hex nut. This 4.7x increase in bearing area is particularly beneficial when fastening to aluminum castings, thin steel stampings, or composite materials that are susceptible to creep or crushing under high surface pressure. The serrated underside of the flange provides mechanical resistance to loosening by biting into the joint surface, supplementing the thread friction that is the primary locking mechanism.

The nut body is manufactured from medium carbon steel (C35) with a minimum proof load stress of 800 MPa (property class 8). The threads are tapped after heat treatment to achieve the correct 6H internal thread tolerance, ensuring smooth engagement with class 6g bolts while maintaining adequate thread engagement depth. The flange is formed integrally with the nut body through cold forging, creating a seamless transition that eliminates the weak point present in two-piece flange nut designs. The zinc electroplate with clear chromate conversion coating provides 120 hours of salt spray resistance.

Technical specifications: thread M12x1.5 or M12x1.25 per application; property class 8; proof load >800 MPa; flange diameter 24mm; flange thickness 2.5mm; serration pitch 1.0mm; coating: zinc electroplate, clear chromate; temperature range -40°C to 120°C.

Flange nuts are used on the SYM Jet X 125I for axle retention, shock absorber mounting, engine mount attachment, and various chassis connections. The integrated flange eliminates the need for a separate washer, reducing parts count and ensuring that the washer is always present and properly positioned. During installation, torque to the OEM specification using a torque wrench. The serrated flange will mark the joint surface—this is normal and does not indicate over-torquing. Do not use thread-locking compound with flange nuts, as the compound can fill the serrations and reduce their anti-rotation effectiveness. Replace flange nuts that show thread damage, flange cracking, or loss of serration sharpness.