[Turnkey]

I noticed when going through construction that has the radar billboards my speedometer is 3 MPH faster than reported speed. This is both northbound and southbound, at least 4 different times. Any idea of what it may be before I take her in?

 

[Rattler1]

I noticed when going through construction that has the radar billboards my speedometer is 3 MPH faster than reported speed. This is both northbound and southbound, at least 4 different times. Any idea of what it may be before I take her in?

Just the way most of them seem to be. Somebody suggested they are being 'robbed' of some warranty.

 

[SuperCrutyPS]

If you have access to a GPS, run the truck with it to see how your speedometer compares. Those construction boards are probably not the most accurate speed sensors.

 

[Turnkey]

That's what I thought. If it is registering faster than it is going, it's putting more miles on the odometer than actually traveled.

Yes, those particular boards are very accurate.

 

[SuperCrutyPS]

Wouldn't hurt to have the dealer look at it. Who knows, maybe they programmed in the wrong tire size. :dunno:

 

[Turnkey]

They are going to look at it Monday. One of the guys was quick to point out that it is within Fords specs. I told the whipper snapper I have owned many vehicles and this is the first one to register wrong. And for the money I paid it had better be spot on.

 

[CUZICAN]

Simple solution, upgrade to 35's, problem solved.

 

[JasonY]

Mine is 3mph off too, I have the corrected speed on my CTS.

Jason

 

[Turnkey]

Sure, why not.. Now if I can just find where my money tree ran off to. lol!!

Simple solution, upgrade to 35's, problem solved.

 

[drunk on diesel]

Most OEM speedos are calibrated high.

This gives the buyer a false sense of high fuel mileage and gets the vehicles out of warranty slightly quicker

 

[Turnkey]

I kind of figured that. Chechecked it against GPS today, and it is 2 mph faster than the GPS.

 

[blwnsmoke]

Mine runs 1-2mph over as well. My 07 did the same thing and my Explorer is 1mph over at 60mph.

Speedometers are not "certified' to be 100% accurate. I doubt your dealer will do anything. The only vehicles I knew that were certified are police cars.

 

[Turnkey]

I hate to say it, but my GMs were always right on the money. How friggin hard can it be to have a correct speedometer?

 

[sbluke55]

My last few work trucks where an 09,11,13 and a 14 f250's and they where all off by 2 mph. When doing 75 on the speedo the truck was only doing 73. On my Chevy 2500 work trucks 11 and a 12 and a few loaner trucks I got when mine was in the shop. They where all of by 2 mph the other way. When doing 75 on the speedo the truck was going 77. I've checked this off of gps and used a speed trap sign on the interstate that I pass every day.

 

[Turnkey]

When out and about today, it was only off by 1mph according to GPS. So is it breaking itself in or what? I am quite befuddled.

 

[CUZICAN]

The amount it is off will vary by how fast you are going, the slower you are going, the closer it will be to matching; where as the faster you are going, the larger the difference will be.

 

[Turnkey]

Actually, it doesn't matter what speed you are traveling at. It is constantly off by that amount through the whole range of speed which is what befuddles me.

 

[Rattler1]

Actually, it doesn't matter what speed you are traveling at. It is constantly off by that amount through the whole range of speed which is what befuddles me.

Then it is probably how the needle is oriented on the shaft or maybe how which gear tooth it was put in on the speedo assembly.

I would think that if it was some sort of ratio messed up in the mechanism then it would be proportional to the actual speed.

Just thinking out loud as I don't really know.

 

[Turnkey]

One of life's little mysteries.. lol!

 

[RigTrash601]

I threw some 35" tires on mine, it's accurate now!:nod: