Speedometer Accuracy

[Bill #5 Explorer]

2011 Limited

I checked the accuracy of my speedo, and digital readout (when in cruise control) today VS my Garmin (I know it to be dead-on accurate) and as expected the Explorer reads out slightly fast.

Only 1 MPH. This is very-very common with many cars I own. My prior Explorer, the 2007, was off (fast) by 3 MPH.

So, when the speedo says I'm doing 70 MPH I am actually going 69 MPH.

Have any others checked the accuracy?

 

[uniquename]

You can't really say it's X mph off. It's proportional, if you recheck at a lower speed, it shouldn't be the same off as at 70 mph.

 

[w1kedz]

2011 Limited

I checked the accuracy of my speedo, and digital readout (when in cruise control) today VS my Garmin (I know it to be dead-on accurate) and as expected the Explorer reads out slightly fast.

Only 1 MPH. This is very-very common with many cars I own. My prior Explorer, the 2007, was off (fast) by 3 MPH.

So, when the speedo says I'm doing 70 MPH I am actually going 69 MPH.

Have any others checked the accuracy?

GPS by design is inaccurate in positioning. They use a smoothing algorithm to calculate speed. Speed on the gps will vary +- .1 to .5 mph with more than 3 satellites connected. With rounding that could be where your 1mph difference is. So when the gps says you are going 69, you may be going 69.5 and the speedometer would round this to 70mph ..

~w1kedz

 

[K-Rod]

I also think it is off and had suspected that myself. We have the speed signs where I live and they have one up now and it shows me going slower than I think I am. Better than the other way around!

 

[fedyfedz]

a little off topic but the speed signs dont pick up my truck for some reason, ive tested this one many times even had a friend try same speed in his 2003 explorer ....

 

[JDraper]

I also think it is off and had suspected that myself. We have the speed signs where I live and they have one up now and it shows me going slower than I think I am. Better than the other way around!

Speed signs aren't necessarily calibrated correctly. We have had several in our area, and each one reads a little differently. Driving the same vehicle, I've seen up to a 5mph difference when driving past them at the same speed.

 

[PIUtility]

Speedometer calibration off?

Well, I've played with the truck a few times this week, and finally figured out where the digital speedo was on my PI's gauge cluster. Earlier in the week I noticed the analog gauge was off compared to my GPS, showing about 2-4mph faster than what GPS was indicating. Today after I found the digital readout, it looks to be exactly 1mph slower than GPS is showing. I'd rather have the slower reading clicking less miles over time than one showing more speed. Has anyone had issues like this before, and is this something worth having the dealership attempt a go at correcting?

 

[peterk9]

Well, I've played with the truck a few times this week, and finally figured out where the digital speedo was on my PI's gauge cluster. Earlier in the week I noticed the analog gauge was off compared to my GPS, showing about 2-4mph faster than what GPS was indicating. Today after I found the digital readout, it looks to be exactly 1mph slower than GPS is showing. I'd rather have the slower reading clicking less miles over time than one showing more speed. Has anyone had issues like this before, and is this something worth having the dealership attempt a go at correcting?

As indicated in my PM, I have moved your thread/post to this existing one on the same topic. The first thing I would check is to see if your vehicle has the OEM wheel/tire sizes. I'd be very surprised if most vehicle's aren't experiencing the same thing.

Peter

 

[PIUtility]

my copilot took these today, thoughts?


ETA: I'm running the factory steel wheels and the OEM 245 tires

 

[Sgt1411]

Thats the Police Interceptor Utility gauge graphics, I can see the AUX steering Wheel Switch graphics on the right side of the screen.

Are you still running OEM Goodyear RSA +............. 255/55R18 V Rated?

 

[peterk9]

Thats the Police Interceptor Utility gauge graphics, I can see the AUX steering Wheel Switch graphics on the right side of the screen.

Are you still running OEM Goodyear RSA +............. 255/55R18 V Rated?

His post above says factory steel wheels with OEM 245 tires.

Peter

 

[anonymous]

I'm going to use those pics to fight my next speeding ticket...

 

[dtr]

I'm going to use those pics to fight my next speeding ticket...

good luck

1) they will have a calibration certificate and say these pics from the internet are an anomaly

2) the ticket will likely be for more than +5 mph, so you will be admitting to speeding just less than the ticket indicates

 

[blwnsmoke]

I love the "Certified calibration" lol.

 

[dtr]

I love the "Certified calibration" lol.

I almost said it may or may not be accurate but it will still be accepted by the court. Just how thing work

 

[Coffeyhouse61]

2011 Limited

I checked the accuracy of my speedo, and digital readout (when in cruise control) today VS my Garmin (I know it to be dead-on accurate) and as expected the Explorer reads out slightly fast.

Only 1 MPH. This is very-very common with many cars I own. My prior Explorer, the 2007, was off (fast) by 3 MPH.

So, when the speedo says I'm doing 70 MPH I am actually going 69 MPH.

Have any others checked the accuracy?

I have a 2011 Limited also and noticed the speedometer is 1 mph off .... it reads 45 when actually going 44.

I measured using an Actron OBDII Diagnostic device while performing the drive cycle instructions to get the darn sensors ready for inspection. The Actron was reading 44 and the speedo was 45.

 

[PIUtility]

Well taking it to the dealership was fruitless yesterday, waiting on input from FordService. Was pretty much told the "Certified Calibration" meant nothing and that 10% variance is allowable by Ford standards, and since this isnt my duty vehicle that I shouldnt worry about it.


Yeah, I'll be using another dealership and waiting on word from our resident Ford rep.

 

[FordService]

...waiting on word from our resident Ford rep.

Hi PIUtility,

You should have a PM from me waiting in your inbox.

Crystal

 

[plumbago]

2011 Limited

I checked the accuracy of my speedo, and digital readout (when in cruise control) today VS my Garmin (I know it to be dead-on accurate) and as expected the Explorer reads out slightly fast.

Only 1 MPH. This is very-very common with many cars I own. My prior Explorer, the 2007, was off (fast) by 3 MPH.

So, when the speedo says I'm doing 70 MPH I am actually going 69 MPH.

Have any others checked the accuracy?

Our 2013 XLT with 18" tires reads out exactly the same as above, checked the same way with a Garmin.......

 

[Gooftroop]

My 2014 Limited has a similar issue except that when I set cruise control, the speedometer reads minus 1 or 2 mph. I verified it with police radar where I work (military base)