you were no help
42" deck = 71" belt48" deck = 73.8" belt44" SNOWBLOWER uses V-Belt 131"
To change the belt on a Yardworks 42" riding mower, first, ensure the mower is turned off and disconnected from the power source. Remove the deck by loosening the belt tension and unhooking the deck hangers. Take note of the belt routing, then remove the old belt and replace it with the new one, ensuring it follows the correct path. Reattach the deck, adjust the tension, and verify that everything is secure before starting the mower.
You will need to order a manual on the mower from the manufacturer (I assume Simplicity).
I have Murray 42" cut riding mower that the belt came off. How do I put the belt back on?
A Craftsman 42 deck belt could be smoking because it is rubbing against something. There could also be an oil leak. If you can not find the cause, you should take it to be serviced.
Most LT12H mowers take a #213676 OEM belt or #6885 Gates belt for the blade application
just get new belts they stretch or buy a can of belt grip
the drive belt is 76 length 1.5 width
The 42 inch deck belt is 104 X 1/2 inches.
Impossible to answer without brand and model info.
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.