Drill a hole in it 
Make sure it's a small hole, dead center of the tread. Pump it up tight and put the hole pointed straight down. When it all drained out, put a plug in it. Problem solved.

But, on serious note, it's kind'a like I tell new lift truck trainees at work . . . "Just because you CAN lift it, doesn't mean you SHOULD." You probably need to break it down and get the water out and remount it.