GPS as opposed to odometer

[GPFred]

I have a 00 GP 3.0 with 135k. I have replaced all 4 hubs since summer and have had no issues with them. Other than a tire with a busted belt, the ride is smooth. One thing I noticed a couple of weeks back, my wife and I went on a short trip in which we used our Garmin for directions. It also displays the speed based on GPS. I noticed that the speed on the GARMIN was slower than what was showing on the odometer by 4 miles an hour. Anyone have any ideas? Is it anything I should worry about? Thanks for the help.

[00GTP4ME]

I actually tried the same thing with my GPS and had about a 1-2 MPH variance at freeway speeds. Have you ever noticed a variance driving by a guilt box? Know any nice cops that will radar you as a test? The speed they show is probably the most important.

[candywrapper]

Hello.
as far the gps goes, they very acurate as to radar what ever your gps is telling you, thats how fast your going.you proply have different tires on or something.i checked the gps with a handheld radar gun
Don

[CrazyHorst]

My personal thoughts are the OEM Odo and Speedo are very accurate, however are always slightly "conservative" in that they read 1-3 mph optimistic to account for mainly tire OD variations.

While I do realize the GPS is also very accurate, I don't think it "samples" the data as fast as the Odo setup and any transmission time lag (low bandwidth) can be problematic.

I would not worry unless you are getting busted for speeding when all other indications signal that you are in a legal or "safe" range.