Changing out the front and rear sprocket and chain for the first time. Running into a problem into trying to remove the nut to release the front sprocket. I have the lock washer tab up but having no success in loosening the sprocket nut. I have the bike in gear with the rear brake pedal applied but the nut won't come loose. Is it a reverse thread or just a muscle issue? 28mm socket is what I'm using on the nut. Any ideas or help welcome?