The pedal axle is the load-bearing connecting element between the pedal and the crank. It transmits the pedaling force, enables the rotation of the pedal, and is a central safety-relevant component in the bicycle drivetrain.

The pedal axle connects the pedal body to the crank and allows the pedal body to rotate. The pedal axle transmits the power generated by the rider's foot to the crank and thus to the drivetrain.

A high-quality pedal axle ensures:

• efficient power transmission

• smooth pedaling

• long durability of the pedal

• high safety while driving

Especially with road bike, MTB and e-bike pedals, the quality of the pedal axle plays a crucial role.

Structure and function

The pedal axle is usually made of hardened steel or – in the case of high-quality and particularly lightweight pedals – of titanium . It is firmly screwed to the crank and forms the load-bearing element of the pedal.

Functions of the pedal axle:

• Absorption and transmission of pedaling forces

• Pedal body mounting (usually via ball or plain bearings)

• Ensuring a stable, play-free rotation

Without a precisely manufactured pedal axle, the pedal would run unevenly, wear out faster, or in the worst case, break.

Threads and standards

Pedal axles are standardized to ensure compatibility with common cranks:

• Standard thread: 9/16 inch × 20 TPI (industry standard, almost all modern bicycles)

• Left- and right-hand threads:

  • Right pedal: Right-hand thread

  • Left pedal: Left-hand thread (prevents it from loosening on its own while driving)

Older bicycles or children's bicycles occasionally still use 1/2-inch threads , but these are now the exception.

Pedal axle bearing

The pedal axle carries the bearings on which the pedal body rotates. Common variations are:

• Ball bearings (loose or sealed): durable, serviceable

• Industrial bearings: low maintenance, common in modern pedals

• Plain bearings: lightweight and compact, often in combination with ball bearings

The quality of the bearings directly affects the concentricity, efficiency and lifespan of the pedal.

Material and load-bearing capacity

Because high forces act on the pedal axle – especially when standing and sprinting – it is a safety-relevant component. Typical materials:

• Steel: very robust, somewhat heavier

• Chromium-molybdenum steel: high strength at moderate weight

• Titanium: very light, corrosion-resistant, expensive

Cheap or damaged pedal axles can bend or, in extreme cases, break.

Maintenance and replacement

The pedal axle itself is rarely replaced individually, but is part of regular maintenance:

• Occasionally unscrew the pedals and grease the threads.

• Check bearings for smooth operation and play.

• If there is a clicking noise or rough running, service or replace pedals

If the pedal axle is damaged or badly worn, the entire pedal is usually replaced.