GY22172 Idler Pulley Replaces GY20067 Idler Pulley John Deere for John Deere 42" 48" D140 L130 LA145 L120 LA115 L110 D110 D130 LA105 E140 L100 E170 D160 LA130 E160 D105 S100 S100 L111 Decks

What It Is

The GY22172 idler pulley is a replacement part for the belt tension system on select John Deere lawn tractors with 42" and 48" cutting decks. It keeps the drive belt tight and aligned so the blades engage properly.

Fitment & Compatibility

• Check your deck size: This pulley fits 42" (e.g., D140, L130, LA145) and 48" decks (e.g., E140, E170, D160). It will not fit 54" decks.
• Model compatibility: Works with John Deere D100–D160, L100–L130, LA100–LA130, S100–S100, E140, E160, E170, and L111. Verify your exact model on the deck sticker or owner’s manual.
• OEM cross-reference: Replaces OEM part GY20067 (older version) and GY22172 (current). Aftermarket part, not genuine John Deere.
• Measure before buying: Pulley outer diameter should be ~3.75” with a 1/2” bore. If your pulley is larger/smaller, this won’t fit.
• Check belt routing: Some decks use two idler pulleys; confirm you need this specific one (often the flat, smooth pulley, not a grooved one).

Key Things to Know

• Quality is decent for the price – steel construction, sealed bearing. Not as durable as OEM, but fine for residential use.
• Installation is straightforward – remove the old pulley bolt, swap, and tighten. No special tools needed, but a socket and wrench are required.
• Common gotcha: The bearing may have slight play out of the box – if it wobbles noticeably, exchange it. Tighten bolt to ~20 ft-lbs; overtightening can damage the bearing.
• Check belt condition – a worn belt can stress the new pulley. Replace both if the belt is cracked or glazed.

Should You Buy It

Yes, if you have a compatible 42" or 48" John Deere deck and want a budget-friendly replacement for a worn or noisy idler pulley. It’s a solid choice for light to medium residential mowing, but if you mow heavy grass or have a commercial operation, consider the OEM part for longer life.