BIGBearing Solid Steel Seemless Billet Idler Pulley 88663 Rebuildable Replacement Bush Hog Finish Mower MTH600 RDTH72 5-3/4" Diameter Zero Turn Lawn Mower Rotary Cutter Tri Deck Flex Wing Deck Bushhog

What It Is

This is a heavy-duty, rebuildable idler pulley designed for zero-turn mowers, finish mowers, rotary cutters, and flex-wing decks—specifically to replace the OEM pulley on Bush Hog models like the MTH600 and RDTH72. It routes and tensions the deck belt, ensuring consistent blade engagement.

Fitment & Compatibility

Before purchasing, verify these three things:

• Diameter: This pulley is 5-3/4" outside diameter. Measure your existing pulley’s OD to confirm match.
• Bearing bore & shaft size: The center hole must fit your spindle shaft or idler arm. Check if you need a bushing adapter (not included) for smaller shafts.
• Deck type: It’s built for Bush Hog MTH600, RDTH72, and similar tri-deck or flex-wing decks. Also works on many zero-turn mowers with a 5-3/4" idler—cross-reference your model’s part number against OEM #88663.

Key Things to Know

• Rebuildable design: Unlike cheap pressed pulleys, this one can be disassembled to replace the bearing when it wears out, extending service life.
• Solid steel billet: Seamless construction resists cracking under heavy loads—critical for rotary cutters and wide decks.
• Installation: Moderate difficulty. You’ll need a wrench set and possibly a puller to remove the old pulley. No special tools for the new one, but ensure the shaft isn’t worn.
• Common gotcha: The pulley’s thickness may differ from OEM. Check clearance against deck housings and belt guides before tightening.

Should You Buy It

Yes, if you own a Bush Hog MTH600, RDTH72, or similar flex-wing deck and want a rebuildable, long-lasting replacement that won’t deform under stress. It’s overkill for a lightweight residential mower, but ideal for commercial or heavy-use equipment where downtime costs more than the part.