Sh. Flange Bolt 8*60

This aftermarket flange bolt is specified for the SYM Jet 14 125I 125cc, compatible with 2017-2019 model years and matching OEM reference 95701-08060-00. Self-locking fasteners are essential in critical applications where vibration-induced loosening could cause component failure, safety hazards, or expensive secondary damage.

The self-locking mechanism on this M8x60 bolt consists of a nylon insert patch applied to the threads after manufacturing. The nylon (typically Nylon 6,6) is a tough, abrasion-resistant polymer that deforms elastically when the bolt is threaded into a mating tapped hole or nut. This deformation creates a prevailing torque—typically 2-5 Nm—that resists rotation independent of the clamp load applied to the joint. Unlike lock washers that depend on friction against the joint surface, the nylon insert maintains its locking force even when thermal cycling causes the joint to relax slightly. The locking action is effective across the full temperature range from -40°C to 120°C, though prolonged exposure above 150°C can degrade the nylon and reduce locking effectiveness.

The bolt body is manufactured from medium carbon steel (typically C35 or 1035) with a minimum tensile strength of 800 MPa (property class 8.8). The threads are rolled rather than cut, creating a work-hardened surface with improved fatigue resistance and smoother thread engagement. The head is formed as a hexagonal flange that integrates a serrated washer face, distributing clamping force over a wider area and reducing the risk of surface damage to aluminum castings. The dacromet coating (a water-based zinc-aluminum flake system) provides 500+ hours of salt spray resistance per ASTM B117, making this bolt suitable for both engine and chassis applications exposed to road salt and moisture.

Technical specifications: size 8×60; thread pitch 1.25mm coarse; property class 8.8; tensile strength >800 MPa; yield strength >640 MPa; head type: hex flange per ISO 4161; coating: dacromet 500; prevailing torque 2-5 Nm; temperature range -40°C to 120°C; torque specification: follow OEM service manual.

Self-locking bolts are single-use fasteners. The nylon insert undergoes permanent deformation during first installation and will not provide adequate locking torque on reuse. Always replace rather than reinstall these bolts, particularly in safety-critical applications such as brake caliper mounts, steering stem clamps, and engine mounting points. During removal, if the bolt shows any signs of thread damage, galling, or corrosion, discard it immediately. When installing, thread the bolt by hand for the first 3-4 turns to prevent cross-threading, then use a torque wrench to achieve the specified value. Do not apply additional thread-locking compound, as this can interfere with the nylon insert function and make future removal difficult.