Flange Bolt 8*55

Engineered for the SYM Jet 14 125I 125cc assembly and service (2017-2019), this aftermarket flange bolt replaces OEM part 95701-08055-00 with equivalent mechanical properties and corrosion resistance. The flange bolt design represents an evolution in fastener technology that addresses several limitations of traditional bolt-and-washer assemblies.

The primary advantage of the integrated flange is elimination of the separate washer, which can be dropped, installed incorrectly, or forgotten entirely during assembly. More importantly, the flange is permanently concentric with the bolt shank, ensuring that the clamping force is distributed evenly around the bolt axis. With separate washers, eccentric loading can occur if the washer is not perfectly centered, leading to uneven stress distribution and potential joint failure. The flange bolt eliminates this variability, improving joint reliability by 20-30% in critical applications.

The serrated flange underside provides an additional anti-rotation feature through mechanical interlocking with the joint surface. The serrations are typically 0.2mm deep with a 60° included angle, creating microscopic teeth that bite into aluminum castings or steel plates. This mechanical lock is effective even when clamp load is lost due to thermal cycling or vibration, preventing the bolt from backing out until the joint is retorqued. The serrations also break through oxide layers and paint films, establishing direct metal-to-metal contact that improves electrical conductivity for grounding applications.

Material and finish: class 8.8 medium carbon steel, quenched and tempered to 28-32 HRC core hardness; zinc phosphate conversion coating per MIL-DTL-16232; thread class 6g external; head height per ISO 4161.

This flange bolt is used extensively throughout the SYM Jet 14 125I for engine covers, transmission cases, and bodywork attachment. When servicing these components, always replace flange bolts that show thread damage, corrosion pitting, or loss of serration sharpness. During installation, apply torque in a gradual manner—rapid torque application can cause the serrations to skip rather than bite, resulting in a false torque reading and inadequate clamp load. For aluminum castings, verify that the flange diameter does not overhang the boss edge, which could cause cracking under load.