You must break the bead loose and allow it to travel into the groove at the center of the wheel to be able to get it over the edge of the rim. Most easily done with a tire changer in the hands of a skilled operator
Kawasaki
To fix a John Deere RX75 mower stuck in 2nd gear, first, ensure the mower is turned off and safely positioned. Check the gear shift linkage for any disconnections or damage, and inspect the transmission for any obstructions. If necessary, adjust or lubricate the linkage and ensure the transmission is functioning properly. If the issue persists, consulting the owner's manual or a professional technician may be required for further diagnosis.
front tires are 11x4.00-5, and rear tires are 16x6.5-8. I just replaced mine so I know the information is correct. Hope this helps.