John Deere GY21099 Replacement: Compare 7 Options

How to find your model number

Check your model number before you buy a replacement for the GY21099. On a riding mower or lawn tractor the model and serial label is usually under the seat, on the frame beside the seat, or near the battery. Deck parts may also need the deck size, which is often on a decal on top of the deck.

Spring maintenance

Spin each blade by hand (engine off, spark plug wire removed) before the first cut. Grinding, wobble or play in a spindle means it needs replacing.

Maker's part vs aftermarket: the GY21099

We did not find John Deere's own GY21099 on Amazon. 5 brands sell a deck spindle listed as its replacement, including JYLEYJ, POSEAGLE, prime&swift, SCBHWJ.

• Maker's own part: made and sold by the equipment or engine maker (for example John Deere, MTD or Briggs & Stratton). Usually the highest price.
• Aftermarket parts: made by other companies to the same size and fit. Usually cheaper; materials and build quality vary by brand.
• Before you buy: find your equipment's model number (see How to find your model number, above), compare the size of your old part, and confirm the fit on the product page.