John Deere belts are not one-size-fits-all. Each model comes with a specific belt size, usually measured in inches and categorized by function, drive belts, deck belts, or transmission belts. Using the wrong size can affect mower performance, cause premature wear, or even damage the engine.
In this post guide, we’ll give you a detailed JD belt size chart, covering all models from A to Z, plus essential tips for replacement, maintenance, and buying the right belt.
John Deere Belt Size Chart
Mower Deck Belt
| Model | Part Number | Belt Size (inches) |
|---|---|---|
| 100 Series | GX20072 | 103.7 x 0.5 |
| D100 | GX20072 | 103.7 x 0.5 |
| D105 | GX20072 | 103.7 x 0.5 |
| D110 | GX20072 | 103.7 x 0.5 |
| D125 | GX20072 | 103.7 x 0.5 |
| D130 | GX20072 | 103.7 x 0.5 |
| D140 | GX20072 | 103.7 x 0.5 |
| D155 | GX20072 | 103.7 x 0.5 |
| D160 | GX20072 | 103.7 x 0.5 |
| D170 | GX20072 | 103.7 x 0.5 |
| E100 | GX20072 | 103.7 x 0.5 |
| E110 | GX20072 | 103.7 x 0.5 |
| E120 | GX20072 | 103.7 x 0.5 |
| E130 | GX20072 | 103.7 x 0.5 |
| E140 | GX20072 | 103.7 x 0.5 |
| E150 | GX20072 | 103.7 x 0.5 |
| E160 | GX20072 | 103.7 x 0.5 |
| E170 | GX20072 | 103.7 x 0.5 |
| E180 | GX20072 | 103.7 x 0.5 |
| G110 | GX20072 | 103.7 x 0.5 |
| GT235 | M154958 | Not specified |
| L100 | GX20072 | 103.7 x 0.5 |
| L105 | GX20072 | 103.7 x 0.5 |
| L108 | GX20072 | 103.7 x 0.5 |
| L110 | GX20072 | 103.7 x 0.5 |
| L120 | GX20072 | 103.7 x 0.5 |
| L130 | GX20072 | 103.7 x 0.5 |
| LA105 | GX20072 | 103.7 x 0.5 |
| LA115 | GX20072 | 103.7 x 0.5 |
| LA125 | GX20072 | 103.7 x 0.5 |
| LA135 | GX20072 | 103.7 x 0.5 |
| LA145 | GX20072 | 103.7 x 0.5 |
| LA155 | GX20072 | 103.7 x 0.5 |
| LA165 | GX20072 | 103.7 x 0.5 |
| LX172 | M154958 | Not specified |
| S240 | GX20072 | 103.7 x 0.5 |
| X300 | M154958 | Not specified |
| X304 | M154958 | Not specified |
| X310 | M154958 | Not specified |
| X320 | M154958 | Not specified |
| X350 | M154958 | Not specified |
| X360 | M154958 | Not specified |
| X500 | M154621 | 142 x 0.5 |
| X530 | M154621 | 142 x 0.5 |
| X540 | M154621 | 142 x 0.5 |
| Z225 | GX25628 | 104.5 x 0.5 |
| Z235 | GX25628 | 104.5 x 0.5 |
| Z255 | GX25628 | 104.5 x 0.5 |
| Z425 | M158131 | 141.7 x 0.5 |
| Z445 | M158131 | 141.7 x 0.5 |
| Z465 | M158131 | 141.7 x 0.5 |
| Z540R | M174506 | 158.9 x 0.5 |
Related How to Replace Belt on John Deere Z445 Drive Belt Diagram
Traction Drive Belt
| Model | Part Number | Belt Size (inches) |
|---|---|---|
| 100 Series | GX21833 | 92 x 0.5 |
| D100 | GX21833 | 92 x 0.5 |
| D105 | GX21994 | 90.3 x 0.5 |
| D110 | GX21833 | 92 x 0.5 |
| D125 | GX21833 | 92 x 0.5 |
| D130 | GX21833 | 92 x 0.5 |
| D140 | GX21833 | 92 x 0.5 |
| D155 | GX21833 | 92 x 0.5 |
| D160 | GX21833 | 92 x 0.5 |
| D170 | GX21833 | 92 x 0.5 |
| E100 | GX21833 | 92 x 0.5 |
| E110 | GX21833 | 92 x 0.5 |
| E120 | GX21833 | 92 x 0.5 |
| E130 | GX21833 | 92 x 0.5 |
| E140 | GX21833 | 92 x 0.5 |
| E150 | GX21994 | 90.3 x 0.5 |
| E160 | GX21833 | 92 x 0.5 |
| E170 | GX21833 | 92 x 0.5 |
| E180 | GX21833 | 92 x 0.5 |
| L100 | GX20305 | 88.9 x 0.5 |
| L105 | GX20305 | 88.9 x 0.5 |
| L108 | GX20305 | 88.9 x 0.5 |
| L110 | GX20305 | 88.9 x 0.5 |
| L120 | GX20305 | 88.9 x 0.5 |
| L130 | GX20305 | 88.9 x 0.5 |
| LA105 | GX21833 | 92 x 0.5 |
| LA115 | GX21833 | 92 x 0.5 |
| LA125 | GX21833 | 92 x 0.5 |
| LA135 | GX21833 | 92 x 0.5 |
| LA145 | GX21833 | 92 x 0.5 |
| LA155 | GX21833 | 92 x 0.5 |
| LA165 | GX21833 | 92 x 0.5 |
| X300 | M154897 | 90 x 0.5 |
| X304 | M154897 | 90 x 0.5 |
| X310 | M154897 | 90 x 0.5 |
| X320 | M154897 | 90 x 0.5 |
| X350 | M169485 | 87.9 x 0.5 |
| X360 | M154897 | 90 x 0.5 |
| X500 | M154897 | 90 x 0.5 |
| X530 | M154897 | 90 x 0.5 |
| X540 | M154897 | 90 x 0.5 |
Related Husqvarna Belt Size Chart(For All Models)
Fan Belt
| Model | Part Number | Belt Size (inches) |
|---|---|---|
| A | AM35409 | 1/2″ x 40″–50″ |
| B | AM35409 | 1/2″ x 40″–50″ |
NOTE: Belt sizes and part numbers depend on deck size, model year, and configuration. Always make verification
How to Identify the Correct Belt for Your JD Equipment
Here are three simple ways to find the right belt size:
- Check the Owner’s Manual: Belt sizes are usually listed in the maintenance section.
- Look on the Mower Deck: Many JD mowers have a sticker with the belt part number and dimensions.
Related Toro Belt Size Chart(Updated For All Models)
Signs Your Belt Needs Replacing
Keep an eye out for these red flags:
- Cracking or fraying on the belt surface
- Belt slipping or squealing during operation
- Uneven cutting patterns
- Visible damage or shredding
OEM vs Aftermarket Belts – What’s Best for You?
| Feature | OEM Belts | Aftermarket Belts |
|---|---|---|
| Quality | High | Varies |
| Fit | Perfect match | May require adjustments |
| Cost | Higher | Lower |
| Warranty | Yes | Usually limited |
OEM belts, such as those from John Deere, are precision-made for your model. Aftermarket options can save money, but not all are created equal.Related Cub Cadet Belt Size Chart(For All Models)
Top Tips for Extending Belt Life
- Clean the deck regularly
- Avoid mowing wet grass
- Don’t overload or overwork your mower
- Perform routine maintenance checks
- Tension belts correctly
How to Install a Replacement JD Belt
Tools You May Need:
- Socket wrench set
- Screwdriver
- Gloves
- Belt diagram for your model
Steps:
- Disconnect the spark plug for safety.
- Remove the mower deck.
- Take off the old belt.
- Route the new belt using the belt diagram.
- Reinstall the deck and test the system.
Related Briggs and Stratton Belt Size Chart(For All Models)
Common Mistakes to Avoid When Replacing JD Belts
- Buying the wrong size
- Skipping the belt diagram
- Over-tightening the belt
- Ignoring tensioner pulley conditions
- Using old pulleys with a new belt
FAQ
How do I know what size drive belt I need?
To determine the correct drive belt size for your John Deere mower:
- Check the owner’s manual – It usually lists the exact part number and belt size.
- Look at the current belt – Many belts have the size printed on them.
- Use the mower’s model number – Search online, use our chart above or on John Deere’s parts website using your model (e.g., S100, D140).
- Measure manually – If the old belt is missing or broken, use a soft measuring tape or string to measure the belt path and get an approximate length.
Related Gravely Belt Size Chart(For All Models)
What size belt does a John Deere S100 take?
The John Deere S100 uses the following belts:
- Mower Deck Belt (42″): Part number GX20072
- Size: 104 inches long x 0.5 inches wide
- Drive Belt: Part number GX21994
- Size: Approximately 90.3 inches long
Both belts are designed specifically for the S100’s transmission and deck system. Always use OEM parts for best performance.
What size belt is a John Deere Z315E?
The John Deere Z315E typically comes with a 42-inch deck, and its deck belt specification is:
- Part Number: M169485
- Size: Approximately 87.9 inches long x 0.5 inches wide
Double-check your model year, as belt size may vary slightly.
What is the belt length of the John Deere GX20072?
The GX20072 belt, one of John Deere’s most common belts, has the following dimensions:
- Length: 104 inches
- Width: 0.5 inches (1/2 inch)
- Type: V-Belt, used on many 42-inch deck models like the D100, E100, S100, LA100, and L100 Series.
What size is a John Deere S100?
The John Deere S100 is a 42-inch riding lawn tractor, which refers to the cutting deck width. Other size specs:
- Deck Width: 42 inches
- Overall Width with Deck: ~53 inches
- Length: ~69.7 inches
- Height: ~42.5 inches
It’s part of the 100 Series, ideal for residential lawn care.
How many inches is a John Deere 42-inch deck belt?
A John Deere 42-inch mower deck belt (like GX20072) measures:
- Length: 104 inches
- Width: 0.5 inches
This belt is used on many 42″ decks across D100, E100, S100, and LA100 Series tractors.
What causes a John Deere belt to break?
- Improper tension – Too tight or too loose causes friction and slippage.
- Debris buildup – Sticks, grass, or rocks lodged in the pulley system can cut or overstrain the belt.
- Aging or cracking – Over time, rubber dries out, cracks, and weakens.
- Worn pulleys – Damaged or misaligned pulleys increase stress on the belt.
- Incorrect belt installation – Using the wrong size or twisting the belt can cause immediate damage.
- Overloading the mower – Thick or wet grass puts excess strain on the drive and deck belts.
