BOSFLAG idler pulley kit for John Deere 100 Series — 2x GY22172 + 1x GY20629, precision-machined replacement with M10 nuts

These two precision idler pulleys (GY22172 x2 and GY20629 x1) with a 3×M10 flanged nylon nut hardware kit restore smooth belt tracking and consistent deck drive on compatible 100 Series tractors.

If your mower deck is slipping, vibrating, or showing uneven belt wear, worn idler pulleys are often the culprit. This BOSFLAG kit supplies two smaller GY22172 pulleys and one larger GY20629 pulley plus the fasteners you need for a direct replacement on many John Deere 100 Series and similar models. Each pulley is machined for concentric rotation to reduce wobble and extend belt life while matching the original dimensions for an easy swap.

How do these pulleys improve mower deck performance?

Replacing aged or damaged idler pulleys restores proper tension and alignment across the deck belts. That reduces belt slippage, lowers vibration, and helps the blades maintain steady speed under load without changing drive components.

• Precision-machined surfaces for steady belt contact and reduced wear
• Balanced construction to minimize vibration during operation
• Correct inner and outer diameters to match factory belt path geometry

What are the exact dimensions and parts in the kit?

The kit includes two GY22172 idler pulleys and one GY20629 idler pulley plus three M10 flanged nylon nuts for secure mounting. Each pulley lists its nominal inner and outer diameters and overall height so you can confirm fit before installation.

• GY22172: height 1.15 in, bore (ID) 0.65 in, outside diameter (OD) 3.62 in
• GY20629: height 1.15 in, bore (ID) 0.66 in, outside diameter (OD) 6.69 in
• Hardware: 3 × M10 flanged nylon nuts included for direct assembly

Which tractor models are these pulleys compatible with?

This replacement set is intended for a broad range of John Deere 100 Series tractors and related models where the GY22172 and GY20629 pulleys are specified. Always compare the part numbers and measurements with your machine before purchase to ensure compatibility.

• Fits many 100 Series Tractors: 102, 105, 107S, 108 variants, 115, 125, 135, 145, 155, and more
• Compatible with D, L, LA, S, X model prefixes listed in the fitment table
• Also cross-references OE numbers such as GY20067, GY20110, GY22082, AUC17621, Oregon 78-133

How difficult is installation and what should I prepare?

Installing the pulleys is a straightforward mechanical task for anyone comfortable with basic mower maintenance. You’ll need standard hand tools, a safe way to support the mower, and possibly a service manual or photos to replicate belt routing.

• Tools: wrenches/sockets for M10 fasteners and retaining bolts
• Safety: park on a flat surface, disconnect spark plug, and support deck or tractor safely
• Tip: compare new pulleys to old ones to confirm orientation and belt path

Who is this for: This BOSFLAG pulley kit is designed for homeowners, landscapers, and small-fleet technicians maintaining John Deere 100 Series and compatible tractors who need a reliable, off-the-shelf replacement. It’s appropriate for routine maintenance, restoring deck belt reliability, or preparing equipment for peak-cutting season when even belt tension and minimal vibration matter most. If you value OEM-like dimensions, included hardware for a direct swap, and components engineered for steady rotation, this kit offers the parts needed to return the deck drive to dependable service.