Middleburn RS8 X-Type Crank 68/73

Middleburn RS8 X-Type Bike Cranks are precision-engineered for riders seeking strength, stiffness, and lightweight performance. These RS8 bike cranks come complete with the axle, axle nuts, and all necessary fittings, designed for use with 24mm HT2 style external bottom brackets.

The RS8 X crankset weighs approximately 530g including all fittings and features a Q-factor of around 174mm for 73mm frames, providing the ideal balance of comfort, power transfer, and pedalling efficiency. With the axle for 73mm shells the chainstay clearance is 145mm between the arms.

Available in lengths of 165mm, 170mm, and 175mm, and in black or silver finishes, these cranks can be tailored to your bike and style.

All Middleburn RS8 X-Type cranks are fitted with a 24mm axle compatible with Hollow Tech 2 style bottom brackets. They include the Bearing Pre-load Collar and the Spider/UNO Lock Ring. Crank and lock ring colours match by default, but custom combinations are available on request. The non-drive side bolt is silver as standard but can be fitted in black if required.

First developed in 1991, Middleburn cranks have undergone continuous refinement. The RS8 X-Type crank is designed for modern MTB use, compatible with external bottom brackets and push-fit systems (with the appropriate axle). Advanced 3D stress modelling ensures these cranks are among the stiffest on the market while remaining lightweight. Crafted from hot forged 7075 T6 aluminium, the cranks are fully CNC machined, hand-polished, anodised, and finished by hand, guaranteeing consistent quality and precision across every arm.

The difference between the RS8 X-Type and the RS7 X-Type lies in the arm design and axle compatibility. RS8 cranks feature straight blade arms for stiffness and compatibility with various bottom bracket widths (68/73, 83, or 100mm), while RS7 cranks have kinked arms for extra clearance and a slightly wider Q-factor, currently fitting only 68/73mm shells.

The RS8 cranks are designed to work with dedicated X-Type spiders and UNO chainrings to maintain the correct chainline. Whether running standard 50mm or Boost setups, we can build your Middleburn RS8 X-Type cranks to your exact requirements.

Key Features of Middleburn RS8 X-Type Bike Cranks

• Strong and stiff for maximum power transfer
• Lightweight for easier pedalling
• Compatible with 24mm HT2 style bottom brackets
• Optimised clearance to prevent pedal strikes
• CNC machined, hand-polished, and anodised for precision
• Multiple lengths and finishes to suit your bike
• Proven design trusted since 1991.