The John Deere LA135 deck belt part number found is GY20072. The deck belt size found is 104 in (2,642 mm) long by 0.5 in (13 mm) wide. The drive belt size found is 88 in (2,235 mm) long by 0.5 in (13 mm) wide.
John Deere LA135 Belt Size and Part Numbers
| Mower deck belt part number | GY20072 |
|---|---|
| Mower deck belt length | 104 in (2,642 mm) |
| Mower deck belt width | 0.5 in (13 mm) |
| Drive belt length | 88 in (2,235 mm) |
| Drive belt width | 0.5 in (13 mm) |
Belt Size Comparison Chart
Belt length comparison
Belt width comparison
John Deere LA135 Belt Notes
| Mower deck belt note | The John Deere LA135 deck belt listing shows part number GY20072, length 104 in (2,642 mm) and width 0.5 in (13 mm). Use the listed value as a buying guide, not a blind substitute for the deck-specific parts diagram |
|---|---|
| Drive belt note | The John Deere LA135 drive or transmission belt measurement captured here is length 88 in (2,235 mm) and width 0.5 in (13 mm). This is separate from the mower deck belt |
| Fitment note | Before ordering a John Deere LA135 belt, compare the old belt routing, pulley layout and deck size if available. A close-looking belt can still be wrong |
John Deere LA135 Belt Size FAQ
What should you watch when fitting a 104 in (2,642 mm) deck belt on the John Deere LA135?
A 104 in (2,642 mm) deck belt leaves little room for sloppy routing. This is a longer mower belt run, so twist, idler alignment and the belt keeper positions matter. A belt can be the right length and still fail if it is routed wrong. Before blaming the new belt, compare the belt path to the routing decal and make sure it sits on the correct side of each.
Can you replace the John Deere LA135 belt with the same length but different width?
The deck belt width found is 0.5 in (13 mm). That is the common 1/2-inch belt width range. Still match the OEM number because the belt angle, fabric wrap and effective length can differ. A belt with the wrong top width can ride too high or too low in the pulley even if the length looks right
Which John Deere LA135 belt needs more careful length matching?
The deck belt is longer here: deck 104 in (2,642 mm) versus drive 88 in (2,235 mm), about 16 in (406 mm) different. Do not cross-match them just because both are mower belts
Mistakes do happen. Belt specs can change by year, mower deck, pulley layout, serial range and regional parts catalog. Please check the operator manual, belt routing decal, old belt label and official John Deere parts catalog before ordering a replacement belt.

