I was driving the FJ today while using my wife's GPS and noticed that the FJ speedo was reading about 1.5 mph fast compared to the GPS. This was a 10-mile run at 65 mph on a straight road using the cruise control. I suppose I'd prefer for it to read fast as opposed to slow, if it's going to have an error, and it's only about 2% off. Has anyone else measured their speedo error? I'm curious to know how wide a variance there is.
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Re:Speedo Accuracy
Date: 2007/12/30 04:43
By: Runner_Ryan
Status: Admin
Karma: 30
Admin
Posts: 1426
There's hardly any spedometers that are 100% accurate. Especially if you have modifications. Mine is about 20 mph off with the 37's...
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Re:Speedo Accuracy
Date: 2007/12/30 05:40
By: xtfritz
Status: User
Karma: 0
F.J.C.O. n00b
Posts: 2
I have a Tomtom and when it was on my saturn before trading it in for my FJ, it was correct 100% of the time. With the FJ I've noticed it to be dead on until I get to around 45+ mph, and then I'll have anywhere from 1.5-2 mph less than the navigation system. I assume the GPS will be more accurate than my speedo so I go off of its reading. Obviously if you have larger tires, the speedo will be severely off. Cheers.
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Re:Speedo Accuracy
Date: 2007/12/31 03:06
By: fatback
Status: Admin
Karma: 3
Admin
Posts: 163
How do you get the speedo adjusted to correct reading with the larger tires as I plan on replacing mine when it is time with 37" after the 6" lift.
thanks, fatback 2007 FJ Cruiser Voodoo Blue Roof Rack Towing PKG Black Steelies AT with Rear Diff and A-Trac 265/70/17 Goodyear Wrangler Dura Tracs Rock Sliders Indianapolis Area
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Re:Speedo Accuracy
Date: 2008/01/01 00:15
By: Cashnutz73
Status: User
Karma: 1
F.J.C.O. Regular
Posts: 39
roamineye, Most speedometers are off 2 to 3 MPH. You must remember that you are comparing an analog device (Speedometer) to a digital one (GPS). My wife’s POS Beetle was 3 MPH off, her new G6 is 1-2 MPH off, my patrol car is 3-4 MPH off between 30 and 55, and the FJ is 1 maybe 2. One thing you must also account for is that your tires change diameter as they wear out. A tire that makes you go 1-2 over the shown speed when it's new may make you 1-2 under when it's bald. Also, most new vehicles have digital speed sensors that show the speed to you as analog. These sensors can lag behind during acceleration and deceleration. fatback- it's nice to see that someone has a clue about speedometer change due to bigger tires. I love seeing the expression on people's faces when I ask them on the side of the road if they had their speedometer adjusted after putting bigger tires(1%) or wheels(99%) on their vehicle. Most people don't know the #1 rule for modding their vehicle: Know how your vehicle will be effected.
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