139-2399 Mower Deck Belt, Traction Drive Cogged Belt Fit for Toro TimeCutter & Exmark Quest 74683 74685 74687 74690 74691QZE725GKC42200 QZE725GKC50200 Lawn Mowers

What It Is

This is a cogged (notched) traction drive belt that transfers power from the engine to the mower’s drive wheels on select Toro TimeCutter and Exmark Quest zero-turn mowers. It’s also used for the mower deck belt on some models, so double-check your application.

Fitment & Compatibility

Before buying, verify these specifics:

• Deck size: Fits 42”, 50”, and 60” decks depending on model. Not all sizes work with every machine.
• Exact model numbers: Compatible with Toro TimeCutter models 74683, 74685, 74687, 74690, 74691, and Exmark Quest models QZE725GKC42200, QZE725GKC50200.
• OEM vs. aftermarket: This is a non-OEM replacement. It may differ slightly in length or tension from the genuine Toro part (117-2738 or similar).
• Measure your old belt: Lay it flat and measure the length (outside circumference) and width. Typical cogged belt for these models is about 1/2” wide. If your belt is a different length, this won’t fit.

Key Things to Know

• Quality concerns: With a 3.4 rating and only 9 reviews, some users report premature wear or stretching. Cogged belts are designed for grip, but cheaper materials may fail faster than OEM.
• Installation difficulty: Moderate. You’ll need to remove the deck, release tension from the idler pulley, and route the belt around all pulleys. A diagram helps—take a photo before removing the old belt.
• Common gotcha: The cogged side must face the pulleys. Installing it backward will cause slipping and rapid wear.
• Check pulley condition: Worn or rough pulleys will shred any belt quickly. Inspect for cracks or burrs before installing.

Should You Buy It

This belt is a budget-friendly option if you’re okay with potential shorter lifespan and can verify fitment against your specific model and deck size. If you want guaranteed durability and easy return compatibility, stick with the OEM Toro or Exmark belt.