PSOM Calibration

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Oct 30, 2024 | 09:36 AM

NMc721

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PSOM Calibration

I have a 1995 F150 the speedometer calibration is off, I have 2 tries left to correct it. My tires are Goodyear Wranglers, size is 31x10.5R15. Revs/Mile is 685. So 685x108/8000 = 9.2475. Would it be necessary to round it to 9.25? Because when I didn’t round the Speedometer gauge sits close to 10MPH while in park.

Oct 30, 2024 | 10:30 AM

My4Fordtrucks

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Sorry. Can’t help with that. Why are you changing the calibration? 31” tires should be what was the original size. At least that was what my ‘94 had when converted from metric to a flotation tire. Did you have bigger/smaller tires on it before? How far off was the speedometer?

Oct 30, 2024 | 10:40 AM

NMc721

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Quote:

Originally Posted by My4Fordtrucks

When I bought the truck, the speedometer was bouncing all over the place. Now that i have it somewhat calibrated, it seems to be fine up til 40 mph and then it bounces again. The previous owner bought the tires, they’re the same size as stock. Not sure what the original calibration is. when I got the truck, it was calibrated at 9.18

Oct 30, 2024 | 11:19 AM

My4Fordtrucks

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I doubt the calibration is causing the bouncing speedometer. The speed would be off but the needle sweep would still be smooth with the wrong setting.