I came up with 35 1/2 inches center to center with the brackets measuring and 35 5/8 inches subtracting the inside stantion to stantion (33 7/8) from the outside stantion to stantion (37 1/8) equals 3 1/2 divided by 2 (1 3/4) added to the 33 7/8 and subtracted from the 37 1/8. Here are pics of the measurement.