116x15 inch
It had a 10 inch molboard.
The John Deere LX172 38 inch blade deck uses a 65 by 1/2 inch V belt. If you ask for a 65 inch belt at an auto parts or hardware store, there is no need for a multi-numeral part number.
4L 63 inch
The John Deere LA130 is a model of riding lawnmower produced by the John Deere Company. The mower uses a 48 inch mower belt. Replacement mower belts are available online and at specific retailers.
To install the belt for John Deere, first get his permission. Once one has hi permission, select a belt for him. Once the belt is selected, proceed and wear the belt for him.
here is a diagram that might be helpful: https://jdparts.deere.com/partsmkt/document/english/featbene/L120_L130_48_3N1deck.pdf
The 42 inch deck belt is 104 X 1/2 inches.
.025 (or 25 Thousandths of an inch). Straight from my JD dealer. Bought a set today.
One might learn how to install a 42 inch deck belt on a John Deere lawnmower by looking at their user manual. A better route to this may be to take it to a lawn mower shop for repair.
Its all spring loaded. No adjustments needed.
I don't think you can . If. It is slipping off you may have a bent spindle, if this is the case you need to go back to the dealer.