Shimano XT M8100 2-piston rear MTB disc brake (without disc) - IM8100JRRXRA170

The Deore XT M8100 reShimano (part no. IM8100JRRXRA170) is a 2-piston hydraulic rear disc brake designed for cross-country, marathon and light trail mountain biking. It is supplied without a disc, allowing you to pair it freely with the Shimano rotor best suited to your setup.

Part of the XT M8100 range, it incorporates high-end technologies from Shimano such as Servo Wave, ensuring more progressive braking, a faster response and excellent modulation. The lever also offers reach adjustments and increased stiffness for precise control on all types of terrain.

Technical specifications

• Brand: Shimano
• Range: Deore XT M8100
• Part number: IM8100JRRXRA170
• Type: rear hydraulic disc brake
• Number of pistons: 2
• Mounting: Post Mount
• Technology: Servo Wave Action
• Fluid: mineral oil Shimano
• Compatibility: XC / marathon / trail mountain bikes
• Supplied: without disc
• Assembly: ready to bleed (pre-assembled depending on kit version)

Key features

• Powerful and progressive braking Shimano XT
• Excellent modulation for control on descents
• Sturdy lever with short, responsive travel
• Tool-free reach adjustment
• Servo Wave system for rapid pad engagement
• Compatible with a wide range of modern MTB frames
• A reliable and tried-and-tested solution for heavy-duty use

FAQ

Does this brake come ready to fit?

Yes, depending on the version, it may be pre-assembled and pre-filled, but adjustment and bleeding may be required after installation.

Is the disc included?

No, this model is sold without a rotor; you’ll need to choose one separately depending on your riding style (XC, trail, etc.).

Is this brake suitable for enduro?

It is primarily optimised for XC and light trail riding. For serious enduro riding, Shimano offers 4-piston versions (M8120).

Can it be used with other Shimano levers?

Yes, Shimano XT hydraulic systems are generally compatible with other levers from the same generation (using mineral oil Shimano).

What is the difference compared to a 4-piston brake?

The 2-piston system prioritises weight and modulation, whilst the 4-piston system offers more power for long, technical descents.