I have 285/75/R16 tires on my Expedition, factory spec for my model is 255/70/R16, so my speedo runs slow.
Has anybody had their wheels calibrated/computer re-programmed or have any suggestions of how to go about it ? (Should I go to a Ford Dealership)

I got stopped for speeding today doing 71mph in a 55 zone. My speedo was reading about 63/64mph & even the cop (VA), suggested getting it calibrated to find out my correct speed, as he told me he wouldn't have pulled me over if I'd actually been going 63/64mph.

Also do u think I should just pay $35 & get a print out of my speedo reading & take it to court & hope the Judge reduces my fine, or just charges me with faulty equipment ?
Or pay $$$ to get the thing calibrated, or re-progrmaed?

 

I know that you can buy a progeammer such a Hypertech power programmer 3 and calibrate for tire size. I to have the same exact problem with my 285 BFGoodrich's.

 

It depends on what year you have. The early years are calibrated by changing a small gear in the transmission and later models must be calibrated by being reprogrammed.

I also have 285's on my Expy and know that the speedo is off by right at 10%. Hence it is very easy to tell how fast I'm going....50=55, 60=66, 70=77, etc.

 

>Also do u think I should just pay $35 & get a print out of
>my speedo reading & take it to court & hope the Judge
>reduces my fine, or just charges me with faulty equipment ?
>Or pay $$$ to get the thing calibrated, or re-progrmaed?


Spike, the others here have you pretty well covered on the 'fix'. Now let me give you some quick advice (for what it's worth *Free*) as I have had the unfortunate experiance of having reaped many a speeding ticket (not at all to be meant as a brag as it is indeed never a good thing)

I have traveled the 48 states extensivly over the last 16 yrs in my work with most of it being on the road averaging anwahere from a low of 500 to as much as 2000 miles a week (no not in a big rig, mainly in either a pickup truck or E series van.

The most important thing I learned, other then being polite and respectful to the aressting officer, is to never admit guilt. This is a very easy ticket to beat assuming that you have an otherwise clean driving record. Get you speedometer calibration checked (be sure to bring your ticket with you when you have this done) and go to court.

The very worst that can happen is the judge finds you guilty as charged and your out the $35 it cost for the calibration, the fine & court cost and the half day of work (not to mention increased insurance rates)

BUT, in my experiance, you are far more likily to at least have it reduced to 1-9 mph over the limit (a savings of a point against your license) though it would be much likily that the judge would offer you the option of spending a saturday in a defensive driving class in exchange for a dismisal. which would leave you a clean, insurance rate friendly driving record

Heck, I once drove 185 miles to make it to court to fight a ticket and when the judge asked why I drove all that way I responded 'because I'm not guilty' and he responded 'case dismissed, your free to go'

Note: It's easier to keep a clean driving record then it is to finally fight a ticket when you already have a couple on your record. Besides, I say it's mostly a revenue game, make'em earn it.