I use these belts to replace broken belts on the 42” deck of a John Deere X300 riding mower which breaks all too often. I believe this is a VERY common problem with this particular mower. I call it the ‘John Deere X300 Super Belt Breaker😊. Due to the cost of these belts, I am EXTREMELY glad I found V Belt Guys which supplies these quality belts for a much better price than other sources.
During the course of owning this John Deere X300 mower, I have tried a number of things to try to stop it from breaking the deck belt with very limited success.
But most recently I installed a washer to serve as a spacer beneath the idler pulley located at the rear of the deck, and never lowering the deck below the 2 3/4 indicator when mowing. After doing these these things, I have not had any more deck belts to break. This leads me to believe the problem is related to the steep angle of the belt between the drive pulley on the bottom of the engine and the idler pulley mounted on the rear of the deck … I believe when this angle becomes too severe, the belt tries to jump off the pulleys, binds somewhere along the travel of the belt and the belt is broken by the force of the engine.
For anyone experiencing similar problems with a John Deere X300 mower with a 42” deck, I would certainly recommend installing a spacer washer(s) beneath the rear idler pulley on the deck (to raise the idler pulley slightly) and not lowering the deck below the 2 3/4 level when mowing. I would be very interested in hearing results from anyone who takes this advice.
Hope this suggestion helps other folks who have been experiencing this VERY frustrating AND EXPENSIVE problem with John Deere X300 mowers with 42” decks.
