for the 737-700 ,the distance between main wheels is 5.7 m,and between nose and main gear is 12.6 m.The minimum width of pavement for 180 turn is 65' (300series)/66'(-700s) ,so about 20 m.
You have to keep this in mind in case you want the planes to do a backtrack on the rwy with a 180 turn on it.