The ROP Shop Pair of Chain Tensioners for 20x8x8, 20x10x8, 23x8.5x12 Yard Garden Tractor

What It Is

This is a pair of chain tensioners designed to maintain proper tension on the blade drive chains of riding mowers and garden tractors, specifically for decks equipped with 20x8x8, 20x10x8, or 23x8.5x12 tires. They prevent chain slap, reduce wear, and ensure consistent blade engagement.

Fitment & Compatibility

• Tire sizes: Only fits decks with 20x8x8, 20x10x8, or 23x8.5x12 tire sizes. Measure your tire sidewall markings to confirm.
• Deck type: Intended for side-discharge or mulching decks with a chain-driven blade spindle system (common on older MTD, Yard-Man, and Troy-Bilt models). Not for belt-driven decks.
• OEM vs aftermarket: Aftermarket replacement. Cross-reference with OEM part numbers like 731-0662, 731-0662A, or 731-0662B. Verify your existing tensioner bracket hole spacing (usually 3.25” center-to-center).
• What to measure: Check the chain pitch (typically #41 or #40) and the width of the tensioner slot (should fit a 0.5” bolt). If your deck uses a different bolt pattern or chain size, these won’t work.

Key Things to Know

• Quality: Basic steel construction with a zinc-plated finish. Adequate for light-to-medium use, but may wear faster than OEM on heavy-duty or commercial decks.
• Installation: Easy—bolts directly to existing deck bracket with two 5/16” bolts (not included). No special tools needed. Ensure the chain is not overtightened; leave 1/4” slack.
• Common gotcha: These tensioners are not adjustable—they rely on fixed hole positions. If your chain has stretched significantly, you may need a new chain or a different tensioner with slotted adjustment.
• Note: Sold as a pair, but many decks only use one. Check your deck’s configuration before ordering.

Should You Buy It

If you have a confirmed compatible tire size and deck style, and you want a cheap, functional fix for a loose or noisy blade drive chain, this is a solid budget option. Skip it if you need adjustable tensioning or a heavy-duty replacement for commercial use.