Odometer or GPS?

[Corky]

Just got back from a long road trip and noticed that most of the time the odometer showed one mile per hour faster than the GPS was showing. Anyone have an idea on how to find which one was reading accurate?

 

[bigwebb83]

gps .

 

[snhrph]

GPS x2.

 

[berettashot117]

I use gps only.

 

[kylebacc]

I would tend to believe the GPS as well. It's a speedometer btw

 

[Trevloc]

i am believe the gps is more accurate.

when i went to California after putting nittos on, my speedometer was off by 2 mph. i know this because i passed a radar that told you your speed, and it was dead on with the gps.

weird tho because my speedometer is only off after passing 55mph. needless to say, i use my gps.

 

[Corky]

Thanks for the input guys. I kinda had a hunch that the GPS was more reliable also. That being said, wouldn't my mileage on my odometer be off if the speed being displayed was off?

 

[CXS]

Yes, it would - I'm assuming you're running a larger tire than stock.

 

[kylebacc]

No that would be the other way around. 1 mph faster seems like i could be something like your regular tires are worn down or something? What kinda of tires are you running, and how much tread have you used?

 

[3TonMike]

The gps is way more accurate. Its good though to see that the speed o is that accurate on your rig.
For the most part vehicle manufacturers are allowed to have up to a 10% error in the speed o meter. I don't know which group set that standard, but it had something to do with cost to build a 100% accurate speedometer. This inaccuracy also compensates for vehicle wear, and the millions of different brands of tires. That has been the standard since the dawn of car, long before gps. In fact, local law dawgs tend to not pull you over for speeding. Until your 10% +2 over. To eliminate the " my speedo falls in 10% rule" defense.

I suck at math but 1 mph at 70 is a low enough percentage let me sleep at night.

 

[chayos00]

Since we are on the subject guys, I recently got a Droid phone the HTC incredible and since you can also do gps on the phone would that be as accurate as a standard gps unit? as there is an app that acts as a speedometer and it shows that I am about 1-2 mph slower that my trucks reading. would u trust the phone to be accurate?

 

[ARK_SWAMP_RIDER]

Since we are on the subject guys, I recently got a Droid phone the HTC incredible and since you can also do gps on the phone would that be as accurate as a standard gps unit? as there is an app that acts as a speedometer and it shows that I am about 1-2 mph slower that my trucks reading. would u trust the phone to be accurate?

What's your tire size? If stock, that's believable. If larger than stock, I'd say most definitely the phone is the closest.

 

[chayos00]

What's your tire size? If stock, that's believable. If larger than stock, I'd say most definitely the phone is the closest.

Yup the tires are stock size.

 

[ARK_SWAMP_RIDER]

I'd still lean towards the phone, falls within the OEM "margin of error" for the speedometer.