yo,
Thanks Bebopman for stepping up on this.
BIGGREEN, that 918 was for P265/75R15 size tires, so apparently no one prev to you has touched this.
and in TSB Ford advuses;
"PSOM Conversion Constants for 92-96 Bronco & F Series
TSB 94-16-16 Speedometer Re-Calibration
Publication Date: 10 AUG 1994
ISSUE: Some vehicles may have the Programmable Speedometer Odometer Module (PSOM) re-calibrated for a tire/axle combination that is not approved by Ford Motor Company/Ford Electronics Division.
ACTION: Refer to the appropriate Service Manual Section in the following chart for a comprehensive list of Ford Motor Company/Ford Electronics Division approved tire/axle combinations.
NOTE: FORD MOTOR COMPANY DOES NOT APPROVE OF THE USE OF ANY CONVERSION CONSTANTS OR TIRE/AXLE COMBINATIONS NOT LISTED IN THE CHARTS. RE-CALIBRATION OF THE PSOM'S CONVERSION CONSTANT MAY BE REQUIRED DUE TO A TIRE/AXLE CHANGE (NOT COVERED UNDER MANUFACTURER'S WARRANTY). THE CONVERSION CONSTANT IS A "NUMBER" USED BY THE PSOM TO SCALE OR INTERPRET THE PULSES PER MILE SENT FROM THE SPEED SENSOR SO THAT THE PSOM WILL RETAIN THE FACTORY SET ACCURACY.
THE CONVERSION CONSTANT CAN BE CHANGED A MAXIMUM OF THREE (3) TIMES FOR THE 1992 MODEL YEAR VEHICLES AND A TOTAL OF SIX (6) TIMES FOR THE 1993-94 MODEL YEAR VEHICLES.
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Information Only"
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Upper case is by Ford, not me