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Certified speedometer

peabodyracin

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Is this unit one that would have come from a police car? I've not seen this before. For some reason I always thought certified speedos just had more gradients between the digits.

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Yes , police , sheriff , state troop, ect .
Some plain jane state cars or locals would have them also, fire marshal, ect.
 
They are "certified" to be accurate within a certain spec.
 
A lot of corporate fleets cars were equipped with them - mostly Law enforcement

The certifying process is basically putting it on a dyno and getting the vehicle to predetermines speeds (ie. 15mph, 30mph, 60mph) and verifying the speedo reads within a certain percentage variance. I had to do that on the police vehicles we serviced back when.
 
Is this unit one that would have come from a police car? I've not seen this before. For some reason I always thought certified speedos just had more gradients between the digits.

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I agree with all the other posters as to which cars had certified speedos. I used to do dealership PDI's on police vehicles. Each car with the certified speedo would have a paper in the glove box stating what the actual speed was and what the speedo showed. E.G the speedo might show 60 MPH when the actual speed was maybe 61 or 59 MPH or whatever. This was shown for all speeds from about 20 MPH to max Mph on the speedo. A speedo could be out by 1 MPH at 60 and be out by 3 MPH at 90. Hence the Certified Speedo.
 
Thanks again to all for your input. Kind of a neat piece!
 
Is this unit one that would have come from a police car? I've not seen this before. For some reason I always thought certified speedos just had more gradients between the digits.

View attachment 892809
I had a '64 Dodge 330 Ex Illinois State Police car in '71. It had that certified speedometer. It was to provide law enforcement with a speedometer that could provide a degree of accuracy for reporting on police reports. Was it effective. I don't know. However, I later had a '77 TBird and while browsing a salvage yard up around Beloit, Wi I found a '79 LTD II that was a former police car and had the Certified speedometer in it. Since my T Bird was equipped with an 85 mph speedometer I pulled the Certified speedo from the '79 LTD II and installed it in the T Bird. The LTD speedo was calibrated and marked for speeds up to 140.
 
Thing is that speedymeter was calibrated for a certain rear gear and tire size. It may have been on the money or way off after the swap.
 
Thing is that speedymeter was calibrated for a certain rear gear and tire size. It may have been on the money or way off after the swap.

But it says CERTIFIED. Shouldn't that be good enough? You're right of course. I am just intrigued by it, having not seen one before for that vintage.
 
i practiced criminal defense law for some 28 years in Pittsburgh, PA and often did a lot of "speeding citation" cases. most citations state the driver was exceeding the speed limit by 10 miles per hour or more. on some occasions, usually in small towns, a driver would be charged with exceeding the posted speed limit by "5 mph." in those cases, i would often argue that the average auto manufacturer speedometer can vary 3-7 miles per hour over the actual speed of the vehicle and thus, a driver cited for driving "5 miles per hour" over the posted limit could not be found guilty if he testified that he was "going the posted speed limit" according to the speedometer in his car. in some cases, i brought in articles from various test facilities showing the OEM speedometer deviations. most judges would accept that defense. this "lawyer trick" was happening all over the State so the Pennsylvania Legislature added a statute to the motor vehicle code that provided that if a driver was charged with driving "5 miles per hour over the posted speed limit", a plea of guilty would not result in any points being assessed against the driver's license. in Pennsylvania, it is relatively easy to accumulate enough "points" to have your license suspended for a period of time. that statute ended the "factory speedometer" defense in a lot of my cases as after the statute was passed, i could usually get the policeman to just change the citation to "driving 5 miles per hour over posted speed limit" and the driver would plead guilty, pay the $300.00 fine and court costs and walk out of the courtroom. the drivers were happy, the State of Pennsylvania was happy collecting more fines, and i was happy because i walked out with a decent fee just for "negotiating the deal."
 
Interesting, and welcome to the forum!

The times I got ticketed (many years ago) were for 'exhibition of speed'. In those situations I found it ironic that others appearing for speeding tickets recorded at a speed appreciably higher than I'd been tagged for, got out with much lower fines. Often the offender would have an attorney with them and they'd even negotiate the fine lower. When my turn would come, the judges seemed to like throwing the book at me because of the title of my offense. I vividly recall the court room gasping when my fine was announced. Painful lesson to learn on a service man's pay at the time.
 
Pics below are from my small "stash" of parts. The Mopar box label is copyright dated "1972" and the certified speedo (and calibration slip) must be from 6-74 (see box label).

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BTW, this Mopar p/n 3592927 certified speedo is a perfect fit/replacement for the 85 mph speedo that came in the '79 300 cars (Cordoba SS22L9R).
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Edited 02-02-2020 to correct errors.
 
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Here is a certified speedometer that I took out of a 1964 Savoy Police car that I found in a junkyard several years ago.

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