Are these Speedo vs GPS results normal? -
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Go Back > Models > Jeep Grand Cherokee & Commander Forums > WJ Grand Cherokee Forum > Are these Speedo vs GPS results normal?

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Unread 05-18-2011, 08:12 PM   #1
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2000 WJ 
Join Date: Jun 2005
Location: Victoria, BC Canada, British Columbia
Posts: 1,102
Wj Are these Speedo vs GPS results normal?

So I borrowed a buddies handheld GPS to test my speedo and got some results I wasn't expecting.

At low speeds like 15 MPH actual speed was a touch lower by 1.5 mph

At medium speeds 40 MPH Actual speed was bang on.

At higher speeds 60 MPH actual speed was touch higher 1.5 MPH

I was wondering if this is correct or if I made a mistake?

I have tires which are oversized 30.5"

Also does the speedometer and odometer receive the same data or are they different somehow?

Looking to buy 4" front BDS springs
=KZ= is offline   Reply With Quote Quick reply to this message
Unread 05-19-2011, 01:32 AM   #2
Web Wheeler
Join Date: Apr 2011
Location: Mean Street in a desperate part of town
Posts: 1,710
That's not too far off. You can have the pinion factor adjusted to bring it a little closer.
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Unread 05-19-2011, 01:35 AM   #3
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2004 WJ 
Join Date: Aug 2009
Location: Cape Cod
Posts: 51
The speedometer in my XJ consistently reads about 3-4mph higher than what my gps says and what those police speed trap read outs say, and that's with stock size tires. My WJ seems to be about spot on though, as far as I can tell.
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