# StairMaster 4000PT Stepper Left Pedal Crank Arm (MX166)
The StairMaster 4000PT Stepper Left Pedal Crank Arm is a replacement crank arm for the left pedal assembly on a StairMaster 4000PT stepper. This part helps connect the left pedal area to the stepper’s crank mechanism. If the original left crank arm is damaged, worn, bent, or missing, replacing it can help you restore the equipment’s pedal assembly without replacing the entire machine.
Product Details and Benefits
This product is identified as the **StairMaster 4000PT Stepper Left Pedal Crank Arm**. It is listed under part number and SKU **MX166**. The part is intended for the **left side** of the pedal system, so its position matters when you compare it with the component on your equipment.
A crank arm forms part of the mechanical linkage that transfers pedal movement through the stepper assembly. Because this item serves one specific side of the machine, it can help address a repair need involving the left pedal mechanism. It may suit equipment owners, fitness facility operators, gym technicians, and repair professionals who need a replacement component for a StairMaster 4000PT stepper.
The product page does not provide additional specifications such as material, finish, dimensions, weight, or included hardware. The listing also does not state whether mounting bolts, washers, pedals, or other installation parts come with the crank arm. Review the package contents and compare the existing component before ordering if those details are important to your repair.
Compatibility and Applications
The **MX166 left pedal crank arm is listed for the StairMaster 4000PT Stepper**. It is designed to replace the left crank arm used in that equipment’s pedal assembly. This makes it suitable for maintenance or repair work when the original left-side crank arm no longer functions correctly or needs replacement.
The available product information does not confirm compatibility with other StairMaster models, stepper versions, serial-number ranges, or third-party fitness equipment. Do not assume that this part fits every StairMaster stepper. Confirm that your machine is a StairMaster 4000PT and that the original component matches the left-side crank arm shown in the listing.
## Why Choose This Replacement Part
Choosing the correct side-specific replacement part can simplify a stepper repair and help you avoid ordering a right-side component by mistake. The clearly identified **MX166** part number also gives you a reference for matching this item with maintenance records, repair notes, or an existing parts list.
This replacement crank arm may be a practical choice when you want to repair the pedal linkage on a StairMaster 4000PT rather than search for an entire replacement stepper. It is intended as an individual component for the left pedal crank assembly.
Before You Buy
Verify each of the following before placing your order:
- Brand: **StairMaster**
- Equipment: **4000PT Stepper**
- Component: **Left pedal crank arm**
- Part number and SKU: **MX166**
- Listing serial-number reference: **37486**
Check the side, shape, connection points, and markings on your original part when possible. The product page does not list dimensions, material, hardware, warranty details, or installation instructions, so confirm those requirements with the seller or a qualified fitness-equipment technician before installation.
