On April 21, 1996, at 1345 central daylight time, a Cessna 172N, N739BN, registered to the Capitol City Flyers, Inc., of Marshall, Wisconsin, and operated by a private pilot, ran off runway 12 (2971' x 38' dry/asphalt) after experiencing a crosswind on touchdown at Morey Airport, Middleton, Wisconsin. The airplane sustained substantial damage when it nosed over. The pilot and two passengers reported no injuries. The personal 14 CFR Part 91 flight was operating in visual meteorological conditions. No flight plan was on file. The flight departed Madison, Wisconsin, at 1335 cdt. According to the pilot's written statement, he entered the traffic pattern at Morey Airport for the purpose of picking up his fourth passenger. On final approach to runway 12, the pilot selected 30 degrees of flaps with an indicated airspeed of 65 knots. The pilot used right aileron and opposite rudder to hold the extended centerline. He said the airplane required constant adjusting of the flight controls to maintain extended centerline. The pilot stated, "Touchdown was a bit hard and slightly left of the center. On the roll out the left main tire came off the runway. I attempted to gently steer back to the runway. I was concerned about over correcting the aircraft into a ground roll." The airplane exited the runway to the left and sank in the soft mud shoulder on the side of the runway. The airplane nosed over and came to rest on its back. The pilot listed his lessons learned; "1. For a crosswind landing, flaps should have been set at less than 30 degrees. 2. Although I aim all landings for the centerline mark, I did not adequately consider my reduced safety margin at Rwy 12 Morey(38' wide). 3. Maintain the directional control as aggressively on the roll out as on final approach". The Madison Automatic Weather Observation Station (AWOS) located 8 miles to the east of the Airport, reported winds from 170 degrees at 13 knots with gusts to 18 knots, 11 minutes after the accident. The Cessna 172N Pilot Operating Handbook states for a crosswind landing the following, "...When landing in a strong crosswind, use the minimum flap setting required for the field length... . After touchdown, hold a straight course with the steerable nose wheel and occasional braking if necessary. The maximum allowable crosswind velocity is dependent upon pilot capability as well as aircraft limitations. With average pilot technique, direct crosswind of 15 knots can be handled with safety".