I'm sure you know this but make sure the locking tab is bent completely out of the way. It's is not a left hand thread. I tried using an air impact wrench and that didn't budge it. I wound up using a 1/2 drive breaker bar and a steel pipe section. With the pipe pointing down at about 8:00 o'clock a friend held the bike and I kicked the end of the pipe and it finally broke loose. I couldn't believe how tight that nut was on there. I used to live in Flag for 23 years and rode on the Peaks, the Cinders and in Cottonwood all the time. I miss AZ so bad. Good luck getting that off.