Speedometer Not Matching with GPS Speed

[604Bronco]

I can't help but read that as "foreskin" and think one to two miles of it won't help anything.

Every time I read that I think the same thing. Thank you for having the “balls” to post this!

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[JBHillCountry]

Ford is consistently off from GPS if you have any tires bigger than the base model. The Superduties are the same way. My GPS always reads 2 mph faster due to the Lariat trim having the 20" rims and base being 17". The speedometers are programmed for the base wheel size.

 

[shimmy825]

Every time I read that I think the same thing. Thank you for having the “balls” to post this!

I wavered a bit but decided not to snip the end of my comments.

 

[Zap74]

That’s just Fords way of fckn with the mpg for government testing..lol

 

[Raptor.Tremor.Bronco]

My raptor and tremor are both the same way with waze, they both have factory 35s. Waze reads 2-3 mph less than speedo

 

[L8apex]

The Ford speedo is usually ~3% over actual speed.

But the odometer is accurate. We’re not in an analog world where the two are equivalent.

 

[Cousin Eddie]

I’m pretty sure your 1200 mile discrepancy would only be correct if you drove the entire 60,000 miles AT 80mph. Speedometer error tends to be greater the faster you go. Meaning at lower speeds your margin of error would likely be reduced to something far less significant. Maybe try your Waze at 20 or 40mph and see what it says?

also, it’s too early to say, but I suspect you are reading well within the allowable specs and it’s unlikely that the dealer can do much about it. Also, think about the change in diameter and thus distance travelled per revolution as your tire treads wear out with normal use.

either way though, Good luck and I’m glad to hear that you are loving your new Bronco!

Wouldn't the % error at 80 be the same % error at 20? So even though at 80 mph, 2.5% error would be 78 mph, at 20mph, the equivalent would be 19.5mph. So yes the difference is smaller but the % error is the same, therefore 2.5% error for 60,000 miles would be 1,200 miles regardless of how fast you drive.

Good suggestion though and I'll check it out!

 

[kodiakisland]

I’m putting on taller tires and not recalibrating so I’ll get more miles than my odometer says. Bigger tires and my own extended warranty, win win.

 

[Cousin Eddie]

The Ford speedo is usually ~3% over actual speed.

But the odometer is accurate. We’re not in an analog world where the two are equivalent.

So wouldn't they be getting a 3% bump on how much warranty they have to cover?

It would be interesting to see statistics on how many warranty claims are made at every thousand miles as well as how much an average warranty claim is at each thousand miles.

 

[L8apex]

So wouldn't they be getting a 3% bump on how much warranty they have to cover?

It would be interesting to see statistics on how many warranty claims are made at every thousand miles as well as how much an average warranty claim is at each thousand miles.

Why? The odometer mileage indicates the number of miles the vehicle has traveled.

If you travel 60 miles, at an indicated 60MPH, you will have traveled 60 miles, but in ~63 minutes.

 

[Cousin Eddie]

Why? The odometer mileage indicates the number of miles the vehicle has traveled.

If you travel 60 miles, at an indicated 60MPH, you will have traveled 60 miles, but in ~63 minutes.

Or an indicated 60 miles but actually driven 58.5 miles. Indicated miles will be higher than what is actually driven.

 

[L8apex]

Or an indicated 60 miles but actually driven 58.5 miles. Indicated miles will be higher than what is actually driven.

No that is my point - we're not in an analog world where the odometer is mechanically linked to the speedometer.

Signal A for output shaft revolutions comes in.

For Speedometer:
Signal A * (Math to convert rev to speed) * 1.03% = Speedometer

For Odometer:
Signal A * (Math to convert rev to distance) = Odometer

Notice how the top one has the extra buffer in there?

If the car says it's traveled 60 miles, it's traveled 60 miles*


*Provided vehicle is in its as produced configuration and tires are properly inflated.

 

[smrpilot]

I usually have Waze running whenever I am driving. I also have Waze display the GPS speed. I typically see a slight difference between the GPS speed and the vehicle speedometer; however, on the Bronco, it seems excessive.

At 80 MPH on the Bronco speedometer, Waze displays between 77 and 78 MPH. This equates to approximately 2.5% more miles being logged on the odometer than actually driven. This would end up in me being covered for 1200 miles less on my 60,000 extended warranty I purchased.

Needless to say, this will be on my list of issues to resolve when I take the Bronco in for warranty issues.

Before people start getting super worked up over the issues I am pointing out, let me say (again) this Bronco has surpassed every expectation I have had for it. To me, these issues are minor and easily fixable when Ford and the dealer are given the opportunity to fix them.

Easy fix, you need bigger tires. If you like the Ko2's, 34x10.5's should do the trick to get you up to 33.6" and make the speedo read correct.

 

[Erock]

Every time I read that I think the same thing. Thank you for having the “balls” to post this!

Same

 

[Cousin Eddie]

No that is my point - we're not in an analog world where the odometer is mechanically linked to the speedometer.

Signal A for output shaft revolutions comes in.

For Speedometer:
Signal A * (Math to convert rev to speed) * 1.03% = Speedometer

For Odometer:
Signal A * (Math to convert rev to distance) = Odometer

Notice how the top one has the extra buffer in there?

If the car says it's traveled 60 miles, it's traveled 60 miles*


*Provided vehicle is in its as produced configuration and tires are properly inflated.

Ah, I see your point. But it would come down to where the source of the error is. Is it in the "Signal A" or is it in the algorithm to compute the distance or speed. If it is in one of the algorithms, then one can be off while the other is correct. If it is in the signal A, both speed and distance would be off.

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