Speedometer/Cruise Control calibration?

[jimijammer]

On a long trip yesterday I used the CC a lot and noticed a 2-3 mile discrepancy in the numbers. I set it to 75 mph (Interstate speed limit) and the speedo looked to be about 78. Is there a good way to calibrate or determine which is accurate?

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[89Trooper]

I have the exact same set-up as you do... GT, auto, 3.55 gears.

I have read other threads about it being 2-3 miles off, but mine seems to be pretty accurate.

Obviously, when you use Adaptive Cruise Control (if you have it), it could be set to 70 mph, but if a car is in front of you, you could be traveling slower as the car maintains the distance from the car ahead.

The only way to know for sure which is accurate is to use a GPS. Then you'll know exactly how fast you are traveling.

 

[bislag]

On a long trip yesterday I used the CC a lot and noticed a 2-3 mile discrepancy in the numbers. I set it to 75 mph (Interstate speed limit) and the speedo looked to be about 78. Is there a good way to calibrate or determine which is accurate?

I have the same on my EB w/PP (3.55s, manual).

I figured out what was more accurate by doing a couple drives past one of those roadside radar units that displays your current speed.

 

[Jotis73]

Same here with my GT-PP 2 to 3 MPH off.

 

[Swoope]

Same here with my GT-PP 2 to 3 MPH off.

gps is your friend.. most cars are 2-4 mph slow at ~70.

beers

 

[jimijammer]

I have the same on my EB w/PP (3.55s, manual).

I figured out what was more accurate by doing a couple drives past one of those roadside radar units that displays your current speed.

There is one of those displays close to where I live, I will check next time I drive by it. I just don't want to drift 1-2 miles over the limit and get tagged 5-6 over, enough for a ticket.

 

[B-Fox]

The needle accuracy is only guaranteed within a certain percentage.

 

[docbog]

Just another reason I think Ford missed the mark by not providing a Digital Speedometer App !! Would have been just a matter of program and believe a lot more valuable to the driver than some of the Apps we have.

 

[docbog]

Here is an example of what I am talking about regarding Digital Speedometer. Pictures from my 2014 GMC Sierra.

A very nice feature, I use it a lot. Really miss it on my 2014 GT Premium, was hoping to get it on the new 2016 I have on order.

 

[Swoope]

Just another reason I think Ford missed the mark by not providing a Digital Speedometer App !! Would have been just a matter of program and believe a lot more valuable to the driver than some of the Apps we have.

would not change the accuracy. it would still show the speed of the analog gauge..

and i am a fan of digital speedos, if they can keep up with car conditions..

beers

 

[docbog]

True, but the digital indicator would be more precise to read and should be close to the cruise set.

 

[Khyber]

still it should be 2-3mph off. either the cruise control is wrong or the needle.

mine is the same way though. i've never had another car be off like this though. ever.

 

[sndofprogress]

If you set it to et mode you can see the digital read out of the velocity. I believe this is more accurate than the needle. Compared to the cruise control setting there is a steady error of about 0.75 mph. Which is typical.

So, what I'm saying is that I think the cruise control read out should be trusted over the analog speedometer.

 

[goldengooner]

Just another reason I think Ford missed the mark by not providing a Digital Speedometer App !! Would have been just a matter of program and believe a lot more valuable to the driver than some of the Apps we have.

why dont you lot just get a HUD
loads on eBay for around $40 which has a digital speedo, i am buying one for the coolness factor and that my gauge will read km above the little mph numbers

 

[zuki_dan]

I have noticed this on my car also. I have and old android phone mounted in my car with the YaV1 app for the radar detector that displays GPS speed. The GPS speed matched the CC speed readout better than the actual speedo.

I also heard mention the speedo dial has an optical illusion because it is mounted straight and not pointed at the driver so the driver looks at it at an angle making the pointer look off.

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