Shimano BR-R8170 Caliper Fixing Bolt C2 - Frame Thickness 35mm Bolt Length 44mm

The Shimano Y2J708040 Caliper Fixing Bolt C2 is a genuine Shimano replacement mounting bolt for selected Shimano flat mount road and gravel disc brake calipers.

This bolt is the C2 caliper fixing screw for a 35mm rear mount thickness, with a listed bolt length of 44mm. It is used when fitting compatible Shimano flat mount hydraulic disc brake calipers to frames that require the C2 fixing bolt in this length. Shimano’s dealer documentation lists Y2J708040 as the C2 fixing screw for 35mm frame/rear mount thickness.

As a genuine Shimano spare, it is ideal for replacing a lost, damaged or incorrect caliper mounting bolt during servicing, brake installation or frame builds. Correct bolt length is important for secure brake caliper installation, so always match the fixing bolt to the frame’s mount thickness and the relevant Shimano caliper/service instructions.

Key Features

• Genuine Shimano replacement part
• Part number: Y2J708040
• Caliper fixing bolt / screw C2
• For Shimano flat mount hydraulic disc brake calipers
• Suits 35mm rear mount thickness
• Listed bolt length: 44mm
• Commonly associated with Shimano road/gravel flat mount calipers including Ultegra BR-R8170, Dura-Ace BR-R9270 and GRX BR-RX820 applications
• Ideal for workshop servicing, replacement or custom bike builds

Compatibility Notes

Use this bolt only where the frame’s rear flat mount thickness requires the C2 35mm / 44mm fixing bolt. Shimano’s technical documents show different C and C2 bolt lengths depending on the frame thickness, so checking the frame and caliper requirements before ordering is recommended.