4 Pack Replacement GX20818 GX21510 Mower Deck Spindle Bearing for John Deere L100 L120 L130 LA120 LA130 LA145 LA155 LA165 D110 D120 D130 D145 D155 D165 Models

What It Is

This 4-pack of replacement spindle bearings is designed for the GX20818 and GX21510 spindle housings found on select John Deere 100- and 200-series lawn tractors. These bearings support the mower deck blades and allow them to spin freely; worn bearings cause vibration, uneven cutting, and blade wobble.

Fitment & Compatibility

Before buying, confirm your John Deere model and deck size. This set fits the following models with 42-inch or 48-inch Edge/Accel Deep decks: L100, L120, L130, LA120, LA130, LA145, LA155, LA165, D110, D120, D130, D145, D155, D165. Not compatible with 54-inch decks or older non-Edge decks. OEM part numbers are GX20818 and GX21510 (the GX20818 is the bearing-only version; GX21510 is the full spindle assembly). Measure your spindle shaft diameter—these bearings are for 1-inch shafts. Verify your deck’s spindle housing uses pressed-in bearings (not bolt-on assemblies).

Key Things to Know

• Quality: Aftermarket bearings at this price point are acceptable for residential use; expect shorter lifespan than OEM (John Deere AM137333 or AM136706) under heavy or commercial use.
• Installation difficulty: Moderate. Requires removing the deck, pulling the spindle housing, and pressing out old bearings. A bearing puller or press is recommended—hammering risks housing damage.
• Common gotcha: The 4-pack includes bearings only, not the full spindle housing or seals. You must reuse or replace seals separately. Check for worn housings before pressing in new bearings.
• Torque: Tighten blade bolts to 20–30 ft-lbs after bearing replacement; overtightening can damage new bearings.

Should You Buy It

This 4-pack is a cost-effective fix for DIY homeowners with a 42- or 48-inch John Deere deck who want to replace all four bearings at once (common failure point). It’s not for commercial users or those with 54-inch decks. If you need full spindle assemblies or longer durability, step up to OEM parts.